| /* |
| * Copyright (C) 2015 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.documentsui; |
| |
| import static com.android.documentsui.Events.isMouseEvent; |
| import static com.android.internal.util.Preconditions.checkArgument; |
| import static com.android.internal.util.Preconditions.checkNotNull; |
| import static com.android.internal.util.Preconditions.checkState; |
| |
| import android.support.v7.widget.GridLayoutManager; |
| import android.support.v7.widget.RecyclerView; |
| import android.support.v7.widget.RecyclerView.Adapter; |
| import android.support.v7.widget.RecyclerView.AdapterDataObserver; |
| import android.support.v7.widget.RecyclerView.LayoutManager; |
| import android.support.v7.widget.RecyclerView.OnScrollListener; |
| import android.util.Log; |
| import android.util.SparseBooleanArray; |
| import android.view.GestureDetector; |
| import android.view.GestureDetector.OnDoubleTapListener; |
| import android.view.GestureDetector.OnGestureListener; |
| import android.view.MotionEvent; |
| import android.view.View; |
| import android.graphics.Point; |
| import android.graphics.Rect; |
| import android.graphics.drawable.Drawable; |
| import android.support.annotation.VisibleForTesting; |
| |
| import java.util.ArrayList; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| /** |
| * MultiSelectManager provides support traditional multi-item selection support to RecyclerView. |
| * Additionally it can be configured to restrict selection to a single element, @see |
| * #setSelectMode. |
| */ |
| public final class MultiSelectManager { |
| |
| /** Selection mode for multiple select. **/ |
| public static final int MODE_MULTIPLE = 0; |
| |
| /** Selection mode for multiple select. **/ |
| public static final int MODE_SINGLE = 1; |
| |
| private static final String TAG = "MultiSelectManager"; |
| private static final boolean DEBUG = false; |
| |
| private final Selection mSelection = new Selection(); |
| |
| // Only created when selection is cleared. |
| private Selection mIntermediateSelection; |
| |
| private Range mRanger; |
| private final List<MultiSelectManager.Callback> mCallbacks = new ArrayList<>(1); |
| |
| private Adapter<?> mAdapter; |
| private MultiSelectHelper mHelper; |
| private boolean mSingleSelect; |
| private BandSelectManager mBandSelectManager; |
| |
| /** |
| * @param recyclerView |
| * @param gestureDelegate Option delegate gesture listener. |
| * @param mode Selection mode |
| * @template A gestureDelegate that implements both {@link OnGestureListener} |
| * and {@link OnDoubleTapListener} |
| */ |
| public <L extends OnGestureListener & OnDoubleTapListener> MultiSelectManager( |
| final RecyclerView recyclerView, L gestureDelegate, int mode) { |
| |
| this( |
| recyclerView.getAdapter(), |
| new RuntimeRecyclerViewHelper(recyclerView), |
| mode); |
| |
| mBandSelectManager = new BandSelectManager((RuntimeRecyclerViewHelper) mHelper); |
| |
| GestureDetector.SimpleOnGestureListener listener = |
| new GestureDetector.SimpleOnGestureListener() { |
| @Override |
| public boolean onSingleTapUp(MotionEvent e) { |
| return MultiSelectManager.this.onSingleTapUp(e); |
| } |
| @Override |
| public void onLongPress(MotionEvent e) { |
| MultiSelectManager.this.onLongPress(e); |
| } |
| }; |
| |
| CompositeOnGestureListener<? extends Object> compositeListener = |
| new CompositeOnGestureListener<>(listener, gestureDelegate); |
| final GestureDetector detector = |
| new GestureDetector(recyclerView.getContext(), compositeListener); |
| |
| detector.setOnDoubleTapListener(compositeListener); |
| |
| recyclerView.addOnItemTouchListener( |
| new RecyclerView.OnItemTouchListener() { |
| public boolean onInterceptTouchEvent(RecyclerView rv, MotionEvent e) { |
| detector.onTouchEvent(e); |
| |
| // Only intercept the event if it was a mouse-based band selection. |
| return isMouseEvent(e) && (mBandSelectManager.mIsActive || |
| e.getActionMasked() != MotionEvent.ACTION_UP); |
| } |
| public void onTouchEvent(RecyclerView rv, MotionEvent e) { |
| checkState(isMouseEvent(e)); |
| mBandSelectManager.processMotionEvent(e); |
| } |
| public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {} |
| }); |
| } |
| |
| /** |
| * Constructs a new instance with {@code adapter} and {@code helper}. |
| * @hide |
| */ |
| @VisibleForTesting |
| MultiSelectManager(Adapter<?> adapter, MultiSelectHelper helper, int mode) { |
| checkNotNull(adapter, "'adapter' cannot be null."); |
| checkNotNull(helper, "'helper' cannot be null."); |
| |
| mSingleSelect = mode == MODE_SINGLE; |
| |
| mHelper = helper; |
| mAdapter = adapter; |
| |
| mAdapter.registerAdapterDataObserver( |
| new AdapterDataObserver() { |
| |
| @Override |
| public void onChanged() { |
| mSelection.clear(); |
| } |
| |
| @Override |
| public void onItemRangeChanged( |
| int positionStart, int itemCount, Object payload) { |
| // No change in position. Ignoring. |
| } |
| |
| @Override |
| public void onItemRangeInserted(int positionStart, int itemCount) { |
| mSelection.expand(positionStart, itemCount); |
| } |
| |
| @Override |
| public void onItemRangeRemoved(int positionStart, int itemCount) { |
| mSelection.collapse(positionStart, itemCount); |
| } |
| |
| @Override |
| public void onItemRangeMoved(int fromPosition, int toPosition, int itemCount) { |
| throw new UnsupportedOperationException(); |
| } |
| }); |
| } |
| |
| /** |
| * Adds {@code callback} such that it will be notified when {@code MultiSelectManager} |
| * events occur. |
| * |
| * @param callback |
| */ |
| public void addCallback(MultiSelectManager.Callback callback) { |
| mCallbacks.add(callback); |
| } |
| |
| /** |
| * Returns a Selection object that provides a live view |
| * on the current selection. Callers wishing to get |
| * |
| * @see #getSelectionSnapshot() on how to get a snapshot |
| * of the selection that will not reflect future changes |
| * to selection. |
| * |
| * @return The current seleciton. |
| */ |
| public Selection getSelection() { |
| return mSelection; |
| } |
| |
| /** |
| * Updates {@code dest} to reflect the current selection. |
| * @param dest |
| * |
| * @return The Selection instance passed in, for convenience. |
| */ |
| public Selection getSelection(Selection dest) { |
| dest.copyFrom(mSelection); |
| return dest; |
| } |
| |
| /** |
| * Causes item at {@code position} in adapter to be selected. |
| * |
| * @param position Adapter position |
| * @param selected |
| * @return True if the selection state of the item changed. |
| */ |
| @VisibleForTesting |
| public boolean setItemSelected(int position, boolean selected) { |
| if (mSingleSelect && !mSelection.isEmpty()) { |
| clearSelectionQuietly(); |
| } |
| return setItemsSelected(position, 1, selected); |
| } |
| |
| /** |
| * Sets the selected state of the specified items. Note that the callback will NOT |
| * be consulted to see if an item can be selected. |
| * |
| * @return True if the selection state of any of the items changed. |
| */ |
| public boolean setItemsSelected(int position, int length, boolean selected) { |
| boolean changed = false; |
| for (int i = position; i < position + length; i++) { |
| boolean itemChanged = selected ? mSelection.add(i) : mSelection.remove(i); |
| if (itemChanged) { |
| notifyItemStateChanged(i, selected); |
| } |
| changed |= itemChanged; |
| } |
| |
| notifySelectionChanged(); |
| return changed; |
| } |
| |
| /** |
| * Clears the selection and notifies (even if nothing changes). |
| */ |
| public void clearSelection() { |
| clearSelectionQuietly(); |
| notifySelectionChanged(); |
| } |
| |
| /** |
| * Clears the selection, without notifying anyone. |
| */ |
| private void clearSelectionQuietly() { |
| mRanger = null; |
| |
| if (mSelection.isEmpty()) { |
| return; |
| } |
| if (mIntermediateSelection == null) { |
| mIntermediateSelection = new Selection(); |
| } |
| getSelection(mIntermediateSelection); |
| mSelection.clear(); |
| |
| for (int i = 0; i < mIntermediateSelection.size(); i++) { |
| int position = mIntermediateSelection.get(i); |
| notifyItemStateChanged(position, false); |
| } |
| } |
| |
| private void onLongPress(MotionEvent e) { |
| if (DEBUG) Log.d(TAG, "Handling long press event."); |
| |
| int position = mHelper.findEventPosition(e); |
| if (position == RecyclerView.NO_POSITION) { |
| if (DEBUG) Log.i(TAG, "View is null. Cannot handle tap event."); |
| } |
| |
| onLongPress(position, e.getMetaState()); |
| } |
| |
| /** |
| * TODO: Roll this back into {@link #onLongPress(MotionEvent)} once MotionEvent |
| * can be mocked. |
| * |
| * @param position |
| * @param metaState as returned from {@link MotionEvent#getMetaState()}. |
| * @hide |
| */ |
| @VisibleForTesting |
| void onLongPress(int position, int metaState) { |
| if (position == RecyclerView.NO_POSITION) { |
| if (DEBUG) Log.i(TAG, "View is null. Cannot handle tap event."); |
| } |
| |
| handlePositionChanged(position, metaState); |
| } |
| |
| /** |
| * @param e |
| * @return true if the event was consumed. |
| */ |
| private boolean onSingleTapUp(MotionEvent e) { |
| if (DEBUG) Log.d(TAG, "Handling tap event."); |
| return onSingleTapUp(mHelper.findEventPosition(e), e.getMetaState(), e.getToolType(0)); |
| } |
| |
| /** |
| * TODO: Roll this into {@link #onSingleTapUp(MotionEvent)} once MotionEvent |
| * can be mocked. |
| * |
| * @param position |
| * @param metaState as returned from {@link MotionEvent#getMetaState()}. |
| * @param toolType |
| * @return true if the event was consumed. |
| * @hide |
| */ |
| @VisibleForTesting |
| boolean onSingleTapUp(int position, int metaState, int toolType) { |
| if (mSelection.isEmpty()) { |
| // if this is a mouse click on an item, start selection mode. |
| if (position != RecyclerView.NO_POSITION && Events.isMouseType(toolType)) { |
| toggleSelection(position); |
| } |
| return false; |
| } |
| |
| if (position == RecyclerView.NO_POSITION) { |
| if (DEBUG) Log.d(TAG, "View is null. Canceling selection."); |
| clearSelection(); |
| return false; |
| } |
| |
| handlePositionChanged(position, metaState); |
| return false; |
| } |
| |
| /** |
| * Handles a change caused by a click on the item with the given position. If the Shift key is |
| * held down, this performs a range select; otherwise, it simply toggles the item's selection |
| * state. |
| */ |
| private void handlePositionChanged(int position, int metaState) { |
| if (Events.hasShiftBit(metaState) && mRanger != null) { |
| mRanger.snapSelection(position); |
| |
| // We're being lazy here notifying even when something might not have changed. |
| // To make this more correct, we'd need to update the Ranger class to return |
| // information about what has changed. |
| notifySelectionChanged(); |
| } else if (toggleSelection(position)) { |
| notifySelectionChanged(); |
| } |
| } |
| |
| /** |
| * Toggles the selection state at position. If an item does end up selected |
| * a new Ranger (range selection manager) at that point is created. |
| * |
| * @param position |
| * @return True if state changed. |
| */ |
| private boolean toggleSelection(int position) { |
| // Position may be special "no position" during certain |
| // transitional phases. If so, skip handling of the event. |
| if (position == RecyclerView.NO_POSITION) { |
| if (DEBUG) Log.d(TAG, "Ignoring toggle for element with no position."); |
| return false; |
| } |
| |
| boolean changed = false; |
| if (mSelection.contains(position)) { |
| changed = attemptDeselect(position); |
| } else { |
| boolean canSelect = notifyBeforeItemStateChange(position, true); |
| if (!canSelect) { |
| return false; |
| } |
| if (mSingleSelect && !mSelection.isEmpty()) { |
| clearSelectionQuietly(); |
| } |
| |
| // Here we're already in selection mode. In that case |
| // When a simple click/tap (without SHIFT) creates causes |
| // an item to be selected. |
| // By recreating Ranger at this point, we allow the user to create |
| // multiple separate contiguous ranges with SHIFT+Click & Click. |
| selectAndNotify(position); |
| setSelectionFocusBegin(position); |
| changed = true; |
| } |
| |
| return changed; |
| } |
| |
| /** |
| * Sets the magic location at which a selection range begins. This |
| * value is consulted when determining how to extend, and modify |
| * selection ranges. |
| * |
| * @throws IllegalStateException if {@code position} is not already be selected |
| * @param position |
| */ |
| void setSelectionFocusBegin(int position) { |
| checkState(mSelection.contains(position)); |
| mRanger = new Range(position); |
| } |
| |
| /** |
| * Try to select all elements in range. Not that callbacks can cancel selection |
| * of specific items, so some or even all items may not reflect the desired |
| * state after the update is complete. |
| * |
| * @param begin inclusive |
| * @param end inclusive |
| * @param selected |
| */ |
| private void updateRange(int begin, int end, boolean selected) { |
| checkState(end >= begin); |
| for (int i = begin; i <= end; i++) { |
| if (selected) { |
| boolean canSelect = notifyBeforeItemStateChange(i, true); |
| if (canSelect) { |
| if (mSingleSelect && !mSelection.isEmpty()) { |
| clearSelectionQuietly(); |
| } |
| selectAndNotify(i); |
| } |
| } else { |
| attemptDeselect(i); |
| } |
| } |
| } |
| |
| /** |
| * @param position |
| * @return True if the update was applied. |
| */ |
| private boolean selectAndNotify(int position) { |
| boolean changed = mSelection.add(position); |
| if (changed) { |
| notifyItemStateChanged(position, true); |
| } |
| return changed; |
| } |
| |
| /** |
| * @param position |
| * @return True if the update was applied. |
| */ |
| private boolean attemptDeselect(int position) { |
| if (notifyBeforeItemStateChange(position, false)) { |
| mSelection.remove(position); |
| notifyItemStateChanged(position, false); |
| if (DEBUG) Log.d(TAG, "Selection after deselect: " + mSelection); |
| return true; |
| } else { |
| if (DEBUG) Log.d(TAG, "Select cancelled by listener."); |
| return false; |
| } |
| } |
| |
| private boolean notifyBeforeItemStateChange(int position, boolean nextState) { |
| int lastListener = mCallbacks.size() - 1; |
| for (int i = lastListener; i > -1; i--) { |
| if (!mCallbacks.get(i).onBeforeItemStateChange(position, nextState)) { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| /** |
| * Notifies registered listeners when the selection status of a single item |
| * (identified by {@code position}) changes. |
| */ |
| private void notifyItemStateChanged(int position, boolean selected) { |
| int lastListener = mCallbacks.size() - 1; |
| for (int i = lastListener; i > -1; i--) { |
| mCallbacks.get(i).onItemStateChanged(position, selected); |
| } |
| mAdapter.notifyItemChanged(position); |
| } |
| |
| /** |
| * Notifies registered listeners when the selection has changed. This |
| * notification should be sent only once a full series of changes |
| * is complete, e.g. clearingSelection, or updating the single |
| * selection from one item to another. |
| */ |
| private void notifySelectionChanged() { |
| int lastListener = mCallbacks.size() - 1; |
| for (int i = lastListener; i > -1; i--) { |
| mCallbacks.get(i).onSelectionChanged(); |
| } |
| } |
| |
| /** |
| * Class providing support for managing range selections. |
| */ |
| private final class Range { |
| private static final int UNDEFINED = -1; |
| |
| final int mBegin; |
| int mEnd = UNDEFINED; |
| |
| public Range(int begin) { |
| if (DEBUG) Log.d(TAG, "New Ranger created beginning @ " + begin); |
| mBegin = begin; |
| } |
| |
| private void snapSelection(int position) { |
| checkState(mRanger != null); |
| checkArgument(position != RecyclerView.NO_POSITION); |
| |
| if (mEnd == UNDEFINED || mEnd == mBegin) { |
| // Reset mEnd so it can be established in establishRange. |
| mEnd = UNDEFINED; |
| establishRange(position); |
| } else { |
| reviseRange(position); |
| } |
| } |
| |
| private void establishRange(int position) { |
| checkState(mRanger.mEnd == UNDEFINED); |
| |
| if (position == mBegin) { |
| mEnd = position; |
| } |
| |
| if (position > mBegin) { |
| updateRange(mBegin + 1, position, true); |
| } else if (position < mBegin) { |
| updateRange(position, mBegin - 1, true); |
| } |
| |
| mEnd = position; |
| } |
| |
| private void reviseRange(int position) { |
| checkState(mEnd != UNDEFINED); |
| checkState(mBegin != mEnd); |
| |
| if (position == mEnd) { |
| if (DEBUG) Log.i(TAG, "Skipping no-op revision click on mEndRange."); |
| } |
| |
| if (mEnd > mBegin) { |
| reviseAscendingRange(position); |
| } else if (mEnd < mBegin) { |
| reviseDescendingRange(position); |
| } |
| // the "else" case is covered by checkState at beginning of method. |
| |
| mEnd = position; |
| } |
| |
| /** |
| * Updates an existing ascending seleciton. |
| * @param position |
| */ |
| private void reviseAscendingRange(int position) { |
| // Reducing or reversing the range.... |
| if (position < mEnd) { |
| if (position < mBegin) { |
| updateRange(mBegin + 1, mEnd, false); |
| updateRange(position, mBegin -1, true); |
| } else { |
| updateRange(position + 1, mEnd, false); |
| } |
| } |
| |
| // Extending the range... |
| else if (position > mEnd) { |
| updateRange(mEnd + 1, position, true); |
| } |
| } |
| |
| private void reviseDescendingRange(int position) { |
| // Reducing or reversing the range.... |
| if (position > mEnd) { |
| if (position > mBegin) { |
| updateRange(mEnd, mBegin - 1, false); |
| updateRange(mBegin + 1, position, true); |
| } else { |
| updateRange(mEnd, position - 1, false); |
| } |
| } |
| |
| // Extending the range... |
| else if (position < mEnd) { |
| updateRange(position, mEnd - 1, true); |
| } |
| } |
| } |
| |
| /** |
| * Object representing the current selection. Provides read only access |
| * public access, and private write access. |
| */ |
| public static final class Selection { |
| |
| // This class tracks selected positions by managing two arrays: the saved selection, and |
| // the total selection. Saved selections are those which have been completed by tapping an |
| // item or by completing a band select operation. Provisional selections are selections |
| // which have been temporarily created by an in-progress band select operation (once the |
| // user releases the mouse button during a band select operation, the selected items |
| // become saved). The total selection is the combination of both the saved selection and |
| // the provisional selection. Tracking both separately is necessary to ensure that saved |
| // selections do not become deselected when they are removed from the provisional selection; |
| // for example, if item A is tapped (and selected), then an in-progress band select covers A |
| // then uncovers A, A should still be selected as it has been saved. To ensure this |
| // behavior, the saved selection must be tracked separately. |
| private SparseBooleanArray mSavedSelection; |
| private SparseBooleanArray mTotalSelection; |
| |
| public Selection() { |
| mSavedSelection = new SparseBooleanArray(); |
| mTotalSelection = new SparseBooleanArray(); |
| } |
| |
| /** |
| * @param position |
| * @return true if the position is currently selected. |
| */ |
| public boolean contains(int position) { |
| return mTotalSelection.get(position); |
| } |
| |
| /** |
| * Useful for iterating over selection. Please note that |
| * iteration should be done over a copy of the selection, |
| * not the live selection. |
| * |
| * @see #copyTo(MultiSelectManager.Selection) |
| * |
| * @param index |
| * @return the position value stored at specified index. |
| */ |
| public int get(int index) { |
| return mTotalSelection.keyAt(index); |
| } |
| |
| /** |
| * @return size of the selection. |
| */ |
| public int size() { |
| return mTotalSelection.size(); |
| } |
| |
| /** |
| * @return true if the selection is empty. |
| */ |
| public boolean isEmpty() { |
| return mTotalSelection.size() == 0; |
| } |
| |
| /** |
| * Sets the provisional selection, which is a temporary selection that can be saved, |
| * canceled, or adjusted at a later time. When a new provision selection is applied, the old |
| * one (if it exists) is abandoned. |
| * @return Array with entry for each position added or removed. Entries which were added |
| * contain a value of true, and entries which were removed contain a value of false. |
| */ |
| @VisibleForTesting |
| protected SparseBooleanArray setProvisionalSelection( |
| SparseBooleanArray provisionalSelection) { |
| SparseBooleanArray delta = new SparseBooleanArray(); |
| |
| for (int i = 0; i < mTotalSelection.size(); i++) { |
| int position = mTotalSelection.keyAt(i); |
| if (!provisionalSelection.get(position) && !mSavedSelection.get(position)) { |
| // Remove each item that used to be in the selection but is unsaved and not in |
| // the new provisional selection. |
| delta.put(position, false); |
| } |
| } |
| |
| for (int i = 0; i < provisionalSelection.size(); i++) { |
| int position = provisionalSelection.keyAt(i); |
| if (!mTotalSelection.get(position)) { |
| // Add each item that was not previously in the selection but is in the |
| // new provisional selection. |
| delta.put(position, true); |
| } |
| } |
| |
| // Now, iterate through the changes and actually add/remove them to/from |
| // mCurrentSelection. This could not be done in the previous loops because changing the |
| // size of the selection mid-iteration changes iteration order erroneously. |
| for (int i = 0; i < delta.size(); i++) { |
| int position = delta.keyAt(i); |
| if (delta.get(position)) { |
| mTotalSelection.put(position, true); |
| } else { |
| mTotalSelection.delete(position); |
| } |
| } |
| |
| return delta; |
| } |
| |
| /** |
| * Saves the existing provisional selection. Once the provisional selection is saved, |
| * subsequent provisional selections which are different from this existing one cannot |
| * cause items in this existing provisional selection to become deselected. |
| */ |
| @VisibleForTesting |
| protected void applyProvisionalSelection() { |
| mSavedSelection = mTotalSelection.clone(); |
| } |
| |
| /** |
| * Abandons the existing provisional selection so that all items provisionally selected are |
| * now deselected. |
| */ |
| @VisibleForTesting |
| protected void cancelProvisionalSelection() { |
| mTotalSelection = mSavedSelection.clone(); |
| } |
| |
| private boolean flip(int position) { |
| if (contains(position)) { |
| remove(position); |
| return false; |
| } else { |
| add(position); |
| return true; |
| } |
| } |
| |
| /** @hide */ |
| @VisibleForTesting |
| boolean add(int position) { |
| if (!mTotalSelection.get(position)) { |
| mTotalSelection.put(position, true); |
| mSavedSelection.put(position, true); |
| return true; |
| } |
| return false; |
| } |
| |
| /** @hide */ |
| @VisibleForTesting |
| boolean remove(int position) { |
| if (mTotalSelection.get(position)) { |
| mTotalSelection.delete(position); |
| mSavedSelection.delete(position); |
| return true; |
| } |
| return false; |
| } |
| |
| /** |
| * Adjusts the selection range to reflect the existence of newly inserted values at |
| * the specified positions. This has the effect of adjusting all existing selected |
| * positions within the specified range accordingly. Note that this function discards any |
| * provisional selections which may have been applied. |
| * |
| * @param startPosition |
| * @param count |
| * @hide |
| */ |
| @VisibleForTesting |
| void expand(int startPosition, int count) { |
| checkState(startPosition >= 0); |
| checkState(count > 0); |
| cancelProvisionalSelection(); |
| |
| for (int i = 0; i < mTotalSelection.size(); i++) { |
| int itemPosition = mTotalSelection.keyAt(i); |
| if (itemPosition >= startPosition) { |
| mTotalSelection.setKeyAt(i, itemPosition + count); |
| mSavedSelection.setKeyAt(i, itemPosition + count); |
| } |
| } |
| } |
| |
| /** |
| * Adjusts the selection range to reflect the removal specified positions. This has |
| * the effect of adjusting all existing selected positions within the specified range |
| * accordingly. Note that this function discards any provisional selections which may have |
| * been applied. |
| * |
| * @param startPosition |
| * @param count The length of the range to collapse. Must be greater than 0. |
| * @hide |
| */ |
| @VisibleForTesting |
| void collapse(int startPosition, int count) { |
| checkState(startPosition >= 0); |
| checkState(count > 0); |
| |
| int endPosition = startPosition + count - 1; |
| |
| SparseBooleanArray newSelection = new SparseBooleanArray(); |
| for (int i = 0; i < mSavedSelection.size(); i++) { |
| int itemPosition = mSavedSelection.keyAt(i); |
| if (itemPosition < startPosition) { |
| newSelection.append(itemPosition, true); |
| } else if (itemPosition > endPosition) { |
| newSelection.append(itemPosition - count, true); |
| } |
| } |
| mSavedSelection = newSelection; |
| cancelProvisionalSelection(); |
| } |
| |
| /** @hide */ |
| @VisibleForTesting |
| void clear() { |
| mSavedSelection.clear(); |
| mTotalSelection.clear(); |
| } |
| |
| /** @hide */ |
| @VisibleForTesting |
| void copyFrom(Selection source) { |
| mSavedSelection = source.mSavedSelection.clone(); |
| mTotalSelection = source.mTotalSelection.clone(); |
| } |
| |
| @Override |
| public String toString() { |
| if (size() <= 0) { |
| return "size=0, items=[]"; |
| } |
| |
| StringBuilder buffer = new StringBuilder(mTotalSelection.size() * 28); |
| buffer.append("{size=") |
| .append(mTotalSelection.size()) |
| .append(", ") |
| .append("items=["); |
| for (int i=0; i < mTotalSelection.size(); i++) { |
| if (i > 0) { |
| buffer.append(", "); |
| } |
| buffer.append(mTotalSelection.keyAt(i)); |
| } |
| buffer.append("]}"); |
| return buffer.toString(); |
| } |
| |
| @Override |
| public int hashCode() { |
| return mSavedSelection.hashCode() ^ mTotalSelection.hashCode(); |
| } |
| |
| @Override |
| public boolean equals(Object that) { |
| if (this == that) { |
| return true; |
| } |
| |
| if (!(that instanceof Selection)) { |
| return false; |
| } |
| |
| return mSavedSelection.equals(((Selection) that).mSavedSelection) && |
| mTotalSelection.equals(((Selection) that).mTotalSelection); |
| } |
| } |
| |
| /** |
| * Provides functionality for MultiSelectManager. In practice, use RuntimeRecyclerViewHelper; |
| * this interface exists only for mocking in tests. |
| */ |
| interface MultiSelectHelper { |
| int findEventPosition(MotionEvent e); |
| } |
| |
| /** |
| * Provides functionality for BandSelectManager. In practice, use RuntimeRecyclerViewHelper; |
| * this interface exists only for mocking in tests. |
| */ |
| interface BandManagerHelper { |
| void drawBand(Rect rect); |
| int findEventPosition(MotionEvent e); |
| int getHeight(); |
| void hideBand(); |
| void invalidateView(); |
| void postRunnable(Runnable r); |
| void removeCallback(Runnable r); |
| void scrollBy(int dy); |
| } |
| |
| /** |
| * Provides functionality for BandSelectModel. In practice, use RuntimeRecyclerViewHelper; |
| * this interface exists only for mocking in tests. |
| */ |
| interface BandModelHelper { |
| void addOnScrollListener(RecyclerView.OnScrollListener listener); |
| Point createAbsolutePoint(Point relativePoint); |
| Rect getAbsoluteRectForChildViewAt(int index); |
| int getAdapterPositionAt(int index); |
| int getNumColumns(); |
| int getNumRows(); |
| int getTotalChildCount(); |
| int getVisibleChildCount(); |
| void removeOnScrollListener(RecyclerView.OnScrollListener listener); |
| } |
| |
| /** |
| * Concrete RecyclerViewHelper implementation for use within the Files app. |
| */ |
| private static final class RuntimeRecyclerViewHelper implements MultiSelectHelper, |
| BandManagerHelper, BandModelHelper { |
| |
| private final RecyclerView mRecyclerView; |
| private final Drawable mBandSelectRect; |
| |
| private boolean mIsOverlayShown = false; |
| |
| RuntimeRecyclerViewHelper(RecyclerView rv) { |
| mRecyclerView = rv; |
| mBandSelectRect = mRecyclerView.getContext().getTheme().getDrawable( |
| R.drawable.band_select_overlay); |
| } |
| |
| @Override |
| public int getAdapterPositionAt(int index) { |
| View child = mRecyclerView.getChildAt(index); |
| return mRecyclerView.getChildViewHolder(child).getAdapterPosition(); |
| } |
| |
| @Override |
| public void addOnScrollListener(OnScrollListener listener) { |
| mRecyclerView.addOnScrollListener(listener); |
| } |
| |
| @Override |
| public void removeOnScrollListener(OnScrollListener listener) { |
| mRecyclerView.removeOnScrollListener(listener); |
| } |
| |
| @Override |
| public Point createAbsolutePoint(Point relativePoint) { |
| return new Point(relativePoint.x + mRecyclerView.computeHorizontalScrollOffset(), |
| relativePoint.y + mRecyclerView.computeVerticalScrollOffset()); |
| } |
| |
| @Override |
| public Rect getAbsoluteRectForChildViewAt(int index) { |
| final View child = mRecyclerView.getChildAt(index); |
| final Rect childRect = new Rect(); |
| child.getHitRect(childRect); |
| childRect.left += mRecyclerView.computeHorizontalScrollOffset(); |
| childRect.right += mRecyclerView.computeHorizontalScrollOffset(); |
| childRect.top += mRecyclerView.computeVerticalScrollOffset(); |
| childRect.bottom += mRecyclerView.computeVerticalScrollOffset(); |
| return childRect; |
| } |
| |
| @Override |
| public int getVisibleChildCount() { |
| return mRecyclerView.getChildCount(); |
| } |
| |
| @Override |
| public int getTotalChildCount() { |
| return mRecyclerView.getAdapter().getItemCount(); |
| } |
| |
| @Override |
| public int getNumColumns() { |
| LayoutManager layoutManager = mRecyclerView.getLayoutManager(); |
| if (layoutManager instanceof GridLayoutManager) { |
| return ((GridLayoutManager) layoutManager).getSpanCount(); |
| } |
| |
| // Otherwise, it is a list with 1 column. |
| return 1; |
| } |
| |
| @Override |
| public int getNumRows() { |
| int numFullColumns = getTotalChildCount() / getNumColumns(); |
| boolean hasPartiallyFullColumn = getTotalChildCount() % getNumColumns() != 0; |
| return numFullColumns + (hasPartiallyFullColumn ? 1 : 0); |
| } |
| |
| @Override |
| public int findEventPosition(MotionEvent e) { |
| View view = mRecyclerView.findChildViewUnder(e.getX(), e.getY()); |
| return view != null |
| ? mRecyclerView.getChildAdapterPosition(view) |
| : RecyclerView.NO_POSITION; |
| } |
| |
| @Override |
| public int getHeight() { |
| return mRecyclerView.getHeight(); |
| } |
| |
| @Override |
| public void invalidateView() { |
| mRecyclerView.invalidate(); |
| } |
| |
| @Override |
| public void postRunnable(Runnable r) { |
| mRecyclerView.postOnAnimation(r); |
| } |
| |
| @Override |
| public void removeCallback(Runnable r) { |
| mRecyclerView.removeCallbacks(r); |
| } |
| |
| @Override |
| public void scrollBy(int dy) { |
| mRecyclerView.scrollBy(0, dy); |
| } |
| |
| @Override |
| public void drawBand(Rect rect) { |
| mBandSelectRect.setBounds(rect); |
| |
| if (!mIsOverlayShown) { |
| mRecyclerView.getOverlay().add(mBandSelectRect); |
| } |
| } |
| |
| @Override |
| public void hideBand() { |
| mRecyclerView.getOverlay().remove(mBandSelectRect); |
| } |
| } |
| |
| public interface Callback { |
| /** |
| * Called when an item is selected or unselected while in selection mode. |
| * |
| * @param position Adapter position of the item that was checked or unchecked |
| * @param selected <code>true</code> if the item is now selected, <code>false</code> |
| * if the item is now unselected. |
| */ |
| public void onItemStateChanged(int position, boolean selected); |
| |
| /** |
| * Called prior to an item changing state. Callbacks can cancel |
| * the change at {@code position} by returning {@code false}. |
| * |
| * @param position Adapter position of the item that was checked or unchecked |
| * @param selected <code>true</code> if the item is to be selected, <code>false</code> |
| * if the item is to be unselected. |
| */ |
| public boolean onBeforeItemStateChange(int position, boolean selected); |
| |
| /** |
| * Called immediately after completion of any set of changes. |
| */ |
| public void onSelectionChanged(); |
| } |
| |
| /** |
| * A composite {@code OnGestureDetector} that allows us to delegate unhandled |
| * events to an outside party (presumably DirectoryFragment). |
| * @template A gestureDelegate that implements both {@link OnGestureListener} |
| * and {@link OnDoubleTapListener} |
| */ |
| private static final class |
| CompositeOnGestureListener<L extends OnGestureListener & OnDoubleTapListener> |
| implements OnGestureListener, OnDoubleTapListener { |
| |
| private L[] mListeners; |
| |
| @SafeVarargs |
| public CompositeOnGestureListener(L... listeners) { |
| mListeners = listeners; |
| } |
| |
| @Override |
| public boolean onDown(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onDown(e)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public void onShowPress(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| mListeners[i].onShowPress(e); |
| } |
| } |
| |
| @Override |
| public boolean onSingleTapUp(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onSingleTapUp(e)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onScroll(e1, e2, distanceX, distanceY)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public void onLongPress(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| mListeners[i].onLongPress(e); |
| } |
| } |
| |
| @Override |
| public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onFling(e1, e2, velocityX, velocityY)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean onSingleTapConfirmed(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onSingleTapConfirmed(e)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean onDoubleTap(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onDoubleTap(e)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean onDoubleTapEvent(MotionEvent e) { |
| for (int i = 0; i < mListeners.length; i++) { |
| if (mListeners[i].onDoubleTapEvent(e)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| } |
| |
| /** |
| * Provides mouse driven band-select support when used in conjunction with {@link RecyclerView} |
| * and {@link MultiSelectManager}. This class is responsible for rendering the band select |
| * overlay and selecting overlaid items via MultiSelectManager. |
| */ |
| public class BandSelectManager implements BandSelectModel.OnSelectionChangedListener { |
| |
| private static final int NOT_SET = -1; |
| |
| private final BandManagerHelper mHelper; |
| |
| private boolean mIsActive; |
| private Point mOrigin; |
| private Point mPointer; |
| private Rect mBounds; |
| private BandSelectModel mModel; |
| |
| // The time at which the current band selection-induced scroll began. If no scroll is in |
| // progress, the value is NOT_SET. |
| private long mScrollStartTime = NOT_SET; |
| private final Runnable mViewScroller = new ViewScroller(); |
| |
| public <T extends BandManagerHelper & BandModelHelper> |
| BandSelectManager(T helper) { |
| mHelper = helper; |
| mModel = new BandSelectModel(helper); |
| mModel.addOnSelectionChangedListener(this); |
| } |
| |
| /** |
| * Processes a MotionEvent by starting, ending, or resizing the band select overlay. |
| * @param e |
| */ |
| private void processMotionEvent(MotionEvent e) { |
| if (!isMouseEvent(e)) { |
| return; |
| } |
| |
| if (mIsActive && e.getActionMasked() == MotionEvent.ACTION_UP) { |
| endBandSelect(); |
| return; |
| } |
| |
| mPointer = new Point((int) e.getX(), (int) e.getY()); |
| if (!mIsActive) { |
| // Only start a band select if the pointer is in margins between items, not |
| // actually within an item's bounds. |
| if (mHelper.findEventPosition(e) != RecyclerView.NO_POSITION) { |
| return; |
| } |
| startBandSelect(); |
| } else { |
| mModel.resizeSelection(mPointer); |
| } |
| |
| scrollViewIfNecessary(); |
| resizeBandSelectRectangle(); |
| } |
| |
| /** |
| * Starts band select by adding the drawable to the RecyclerView's overlay. |
| */ |
| private void startBandSelect() { |
| if (DEBUG) { |
| Log.d(TAG, "Starting band select from (" + mPointer.x + "," + mPointer.y + ")."); |
| } |
| mIsActive = true; |
| mOrigin = new Point(mPointer.x, mPointer.y); |
| mModel.startSelection(mOrigin); |
| } |
| |
| /** |
| * Scrolls the view if necessary. |
| */ |
| private void scrollViewIfNecessary() { |
| mHelper.removeCallback(mViewScroller); |
| mViewScroller.run(); |
| mHelper.invalidateView(); |
| } |
| |
| /** |
| * Resizes the band select rectangle by using the origin and the current pointer position as |
| * two opposite corners of the selection. |
| */ |
| private void resizeBandSelectRectangle() { |
| mBounds = new Rect(Math.min(mOrigin.x, mPointer.x), |
| Math.min(mOrigin.y, mPointer.y), |
| Math.max(mOrigin.x, mPointer.x), |
| Math.max(mOrigin.y, mPointer.y)); |
| mHelper.drawBand(mBounds); |
| } |
| |
| /** |
| * Ends band select by removing the overlay. |
| */ |
| private void endBandSelect() { |
| if (DEBUG) Log.d(TAG, "Ending band select."); |
| mIsActive = false; |
| mHelper.hideBand(); |
| mSelection.applyProvisionalSelection(); |
| mModel.endSelection(); |
| int firstSelected = mModel.getPositionNearestOrigin(); |
| if (firstSelected != BandSelectModel.NOT_SET) { |
| setSelectionFocusBegin(firstSelected); |
| } |
| } |
| |
| @Override |
| public void onSelectionChanged(SparseBooleanArray updatedSelection) { |
| SparseBooleanArray delta = mSelection.setProvisionalSelection(updatedSelection); |
| for (int i = 0; i < delta.size(); i++) { |
| int position = delta.keyAt(i); |
| notifyItemStateChanged(position, delta.get(position)); |
| } |
| notifySelectionChanged(); |
| } |
| |
| private class ViewScroller implements Runnable { |
| /** |
| * The number of milliseconds of scrolling at which scroll speed continues to increase. |
| * At first, the scroll starts slowly; then, the rate of scrolling increases until it |
| * reaches its maximum value at after this many milliseconds. |
| */ |
| private static final long SCROLL_ACCELERATION_LIMIT_TIME_MS = 2000; |
| |
| @Override |
| public void run() { |
| // Compute the number of pixels the pointer's y-coordinate is past the view. |
| // Negative values mean the pointer is at or before the top of the view, and |
| // positive values mean that the pointer is at or after the bottom of the view. Note |
| // that one additional pixel is added here so that the view still scrolls when the |
| // pointer is exactly at the top or bottom. |
| int pixelsPastView = 0; |
| if (mPointer.y <= 0) { |
| pixelsPastView = mPointer.y - 1; |
| } else if (mPointer.y >= mHelper.getHeight() - 1) { |
| pixelsPastView = mPointer.y - mHelper.getHeight() + 1; |
| } |
| |
| if (!mIsActive || pixelsPastView == 0) { |
| // If band selection is inactive, or if it is active but not at the edge of the |
| // view, no scrolling is necessary. |
| mScrollStartTime = NOT_SET; |
| return; |
| } |
| |
| if (mScrollStartTime == NOT_SET) { |
| // If the pointer was previously not at the edge of the view but now is, set the |
| // start time for the scroll. |
| mScrollStartTime = System.currentTimeMillis(); |
| } |
| |
| // Compute the number of pixels to scroll, and scroll that many pixels. |
| final int numPixels = computeScrollDistance( |
| pixelsPastView, System.currentTimeMillis() - mScrollStartTime); |
| mHelper.scrollBy(numPixels); |
| |
| // Adjust the y-coordinate of the origin the opposite number of pixels so that the |
| // origin remains in the same place relative to the view's items. |
| mOrigin.y -= numPixels; |
| resizeBandSelectRectangle(); |
| |
| mHelper.removeCallback(mViewScroller); |
| mHelper.postRunnable(this); |
| } |
| |
| /** |
| * Computes the number of pixels to scroll based on how far the pointer is past the end |
| * of the view and how long it has been there. Roughly based on ItemTouchHelper's |
| * algorithm for computing the number of pixels to scroll when an item is dragged to the |
| * end of a {@link RecyclerView}. |
| * @param pixelsPastView |
| * @param scrollDuration |
| * @return |
| */ |
| private int computeScrollDistance(int pixelsPastView, long scrollDuration) { |
| final int maxScrollStep = mHelper.getHeight(); |
| final int direction = (int) Math.signum(pixelsPastView); |
| final int absPastView = Math.abs(pixelsPastView); |
| |
| // Calculate the ratio of how far out of the view the pointer currently resides to |
| // the entire height of the view. |
| final float outOfBoundsRatio = Math.min( |
| 1.0f, (float) absPastView / mHelper.getHeight()); |
| // Interpolate this ratio and use it to compute the maximum scroll that should be |
| // possible for this step. |
| final float cappedScrollStep = |
| direction * maxScrollStep * smoothOutOfBoundsRatio(outOfBoundsRatio); |
| |
| // Likewise, calculate the ratio of the time spent in the scroll to the limit. |
| final float timeRatio = Math.min( |
| 1.0f, (float) scrollDuration / SCROLL_ACCELERATION_LIMIT_TIME_MS); |
| // Interpolate this ratio and use it to compute the final number of pixels to |
| // scroll. |
| final int numPixels = (int) (cappedScrollStep * smoothTimeRatio(timeRatio)); |
| |
| // If the final number of pixels to scroll ends up being 0, the view should still |
| // scroll at least one pixel. |
| return numPixels != 0 ? numPixels : direction; |
| } |
| |
| /** |
| * Interpolates the given out of bounds ratio on a curve which starts at (0,0) and ends |
| * at (1,1) and quickly approaches 1 near the start of that interval. This ensures that |
| * drags that are at the edge or barely past the edge of the view still cause sufficient |
| * scrolling. The equation y=(x-1)^5+1 is used, but this could also be tweaked if |
| * needed. |
| * @param ratio A ratio which is in the range [0, 1]. |
| * @return A "smoothed" value, also in the range [0, 1]. |
| */ |
| private float smoothOutOfBoundsRatio(float ratio) { |
| return (float) Math.pow(ratio - 1.0f, 5) + 1.0f; |
| } |
| |
| /** |
| * Interpolates the given time ratio on a curve which starts at (0,0) and ends at (1,1) |
| * and stays close to 0 for most input values except those very close to 1. This ensures |
| * that scrolls start out very slowly but speed up drastically after the scroll has been |
| * in progress close to SCROLL_ACCELERATION_LIMIT_TIME_MS. The equation y=x^5 is used, |
| * but this could also be tweaked if needed. |
| * @param ratio A ratio which is in the range [0, 1]. |
| * @return A "smoothed" value, also in the range [0, 1]. |
| */ |
| private float smoothTimeRatio(float ratio) { |
| return (float) Math.pow(ratio, 5); |
| } |
| }; |
| } |
| |
| /** |
| * Provides a band selection item model for views within a RecyclerView. This class queries the |
| * RecyclerView to determine where its items are placed; then, once band selection is underway, |
| * it alerts listeners of which items are covered by the selections. |
| */ |
| public static final class BandSelectModel extends RecyclerView.OnScrollListener { |
| |
| public static final int NOT_SET = -1; |
| |
| // Enum values used to determine the corner at which the origin is located within the |
| private static final int UPPER = 0x00; |
| private static final int LOWER = 0x01; |
| private static final int LEFT = 0x00; |
| private static final int RIGHT = 0x02; |
| private static final int UPPER_LEFT = UPPER | LEFT; |
| private static final int UPPER_RIGHT = UPPER | RIGHT; |
| private static final int LOWER_LEFT = LOWER | LEFT; |
| private static final int LOWER_RIGHT = LOWER | RIGHT; |
| |
| private final BandModelHelper mHelper; |
| private final List<OnSelectionChangedListener> mOnSelectionChangedListeners = new ArrayList<>(); |
| |
| // Map from the x-value of the left side of an item to an ordered list of metadata of all |
| // items whose x-values are the same. The list is ordered by the y-values of the items in |
| // the column. For example, if the first column of the view starts at an x-value of 5, |
| // mColumns.get(5) would return a list of all items in that column, with the top-most item |
| // first in the list and the bottom-most item last in the list. |
| private final Map<Integer, List<ItemData>> mColumns = new HashMap<>(); |
| |
| // List of limits along the x-axis. For example, if the view has two columns, this list will |
| // have two elements, each of which lists the lower- and upper-limits of the x-values of the |
| // view items. This list is sorted from furthest left to furthest right. |
| private final List<Limits> mXLimitsList = new ArrayList<>(); |
| |
| // Like mXLimitsList, but for y-coordinates. Note that this list only contains items which |
| // have been in the viewport. Thus, limits which exist in an area of the view to which the |
| // view has not scrolled are not present in the list. |
| private final List<Limits> mYLimitsList = new ArrayList<>(); |
| |
| // The adapter positions which have been recorded so far. |
| private final SparseBooleanArray mKnownPositions = new SparseBooleanArray(); |
| |
| // Array passed to registered OnSelectionChangedListeners. One array is created and reused |
| // throughout the lifetime of the object. |
| private final SparseBooleanArray mSelection = new SparseBooleanArray(); |
| |
| // The current pointer (in absolute positioning from the top of the view). |
| private Point mPointer = null; |
| |
| // The bounds of the band selection. |
| private RelativePoint mRelativeOrigin; |
| private RelativePoint mRelativePointer; |
| |
| private boolean mIsActive; |
| |
| // Tracks where the band select originated from. This is used to determine where selections |
| // should expand from when Shift+click is used. |
| private int mPositionNearestOrigin = NOT_SET; |
| |
| BandSelectModel(BandModelHelper helper) { |
| mHelper = helper; |
| mHelper.addOnScrollListener(this); |
| } |
| |
| /** |
| * Stops listening to the view's scrolls. Call this function before discarding a |
| * BandSelecModel object to prevent memory leaks. |
| */ |
| void stopListening() { |
| mHelper.removeOnScrollListener(this); |
| } |
| |
| /** |
| * Start a band select operation at the given point. |
| * @param relativeOrigin The origin of the band select operation, relative to the viewport. |
| * For example, if the view is scrolled to the bottom, the top-left of the viewport |
| * would have a relative origin of (0, 0), even though its absolute point has a higher |
| * y-value. |
| */ |
| void startSelection(Point relativeOrigin) { |
| mIsActive = true; |
| mPointer = mHelper.createAbsolutePoint(relativeOrigin); |
| |
| recordVisibleChildren(); |
| mRelativeOrigin = new RelativePoint(mPointer); |
| mRelativePointer = new RelativePoint(mPointer); |
| computeCurrentSelection(); |
| notifyListeners(); |
| } |
| |
| /** |
| * Resizes the selection by adjusting the pointer (i.e., the corner of the selection |
| * opposite the origin. |
| * @param relativePointer The pointer (opposite of the origin) of the band select operation, |
| * relative to the viewport. For example, if the view is scrolled to the bottom, the |
| * top-left of the viewport would have a relative origin of (0, 0), even though its |
| * absolute point has a higher y-value. |
| */ |
| void resizeSelection(Point relativePointer) { |
| mPointer = mHelper.createAbsolutePoint(relativePointer); |
| updateModel(); |
| } |
| |
| /** |
| * Ends the band selection. |
| */ |
| void endSelection() { |
| mIsActive = false; |
| } |
| |
| /** |
| * @return The adapter position for the item nearest the origin corresponding to the latest |
| * band select operation, or NOT_SET if the selection did not cover any items. |
| */ |
| int getPositionNearestOrigin() { |
| return mPositionNearestOrigin; |
| } |
| |
| @Override |
| public void onScrolled(RecyclerView recyclerView, int dx, int dy) { |
| if (!mIsActive) { |
| return; |
| } |
| |
| mPointer.x += dx; |
| mPointer.y += dy; |
| recordVisibleChildren(); |
| updateModel(); |
| } |
| |
| /** |
| * Queries the view for all children and records their location metadata. |
| */ |
| private void recordVisibleChildren() { |
| for (int i = 0; i < mHelper.getVisibleChildCount(); i++) { |
| int adapterPosition = mHelper.getAdapterPositionAt(i); |
| if (!mKnownPositions.get(adapterPosition)) { |
| mKnownPositions.put(adapterPosition, true); |
| recordItemData( |
| mHelper.getAbsoluteRectForChildViewAt(i), adapterPosition); |
| } |
| } |
| } |
| |
| /** |
| * Updates the limits lists and column map with the given item metadata. |
| * @param absoluteChildRect The absolute rectangle for the child view being processed. |
| * @param adapterPosition The position of the child view being processed. |
| */ |
| private void recordItemData(Rect absoluteChildRect, int adapterPosition) { |
| if (mXLimitsList.size() != mHelper.getNumColumns()) { |
| // If not all x-limits have been recorded, record this one. |
| recordLimits( |
| mXLimitsList, new Limits(absoluteChildRect.left, absoluteChildRect.right)); |
| } |
| |
| if (mYLimitsList.size() != mHelper.getNumRows()) { |
| // If not all y-limits have been recorded, record this one. |
| recordLimits( |
| mYLimitsList, new Limits(absoluteChildRect.top, absoluteChildRect.bottom)); |
| } |
| |
| List<ItemData> columnList = mColumns.get(absoluteChildRect.left); |
| if (columnList == null) { |
| columnList = new ArrayList<ItemData>(); |
| mColumns.put(absoluteChildRect.left, columnList); |
| } |
| ItemData itemData = new ItemData(adapterPosition, absoluteChildRect.top); |
| int index = Collections.binarySearch(columnList, itemData); |
| if (index < 0) { |
| columnList.add(~index, itemData); |
| } |
| } |
| |
| /** |
| * Ensures limits exists within the sorted list limitsList, and adds it to the list if it |
| * does not exist. |
| */ |
| private void recordLimits(List<Limits> limitsList, Limits limits) { |
| int index = Collections.binarySearch(limitsList, limits); |
| if (index < 0) { |
| limitsList.add(~index, limits); |
| } |
| } |
| |
| /** |
| * Handles a moved pointer; this function determines whether the pointer movement resulted |
| * in a selection change and, if it has, notifies listeners of this change. |
| */ |
| private void updateModel() { |
| RelativePoint old = mRelativePointer; |
| mRelativePointer = new RelativePoint(mPointer); |
| if (old != null && mRelativePointer.equals(old)) { |
| return; |
| } |
| |
| computeCurrentSelection(); |
| notifyListeners(); |
| } |
| |
| /** |
| * Computes the currently-selected items. |
| */ |
| private void computeCurrentSelection() { |
| if (areItemsCoveredBySelection(mRelativePointer, mRelativeOrigin)) { |
| updateSelection(computeBounds()); |
| } else { |
| mSelection.clear(); |
| mPositionNearestOrigin = NOT_SET; |
| } |
| } |
| |
| /** |
| * Notifies all listeners of a selection change. Note that this function simply passes |
| * mSelection, so computeCurrentSelection() should be called before this |
| * function. |
| */ |
| private void notifyListeners() { |
| for (OnSelectionChangedListener listener : mOnSelectionChangedListeners) { |
| listener.onSelectionChanged(mSelection); |
| } |
| } |
| |
| /** |
| * @param rect Rectangle including all covered items. |
| */ |
| private void updateSelection(Rect rect) { |
| int columnStartIndex = |
| Collections.binarySearch(mXLimitsList, new Limits(rect.left, rect.left)); |
| checkState(columnStartIndex >= 0); |
| int columnEndIndex = columnStartIndex; |
| |
| for (int i = columnStartIndex; |
| i < mXLimitsList.size() && mXLimitsList.get(i).lowerLimit <= rect.right; i++) { |
| columnEndIndex = i; |
| } |
| |
| List<ItemData> firstColumn = |
| mColumns.get(mXLimitsList.get(columnStartIndex).lowerLimit); |
| int rowStartIndex = Collections.binarySearch(firstColumn, new ItemData(0, rect.top)); |
| if (rowStartIndex < 0) { |
| mPositionNearestOrigin = NOT_SET; |
| return; |
| } |
| |
| int rowEndIndex = rowStartIndex; |
| for (int i = rowStartIndex; |
| i < firstColumn.size() && firstColumn.get(i).offset <= rect.bottom; i++) { |
| rowEndIndex = i; |
| } |
| |
| updateSelection(columnStartIndex, columnEndIndex, rowStartIndex, rowEndIndex); |
| } |
| |
| /** |
| * Computes the selection given the previously-computed start- and end-indices for each |
| * row and column. |
| */ |
| private void updateSelection( |
| int columnStartIndex, int columnEndIndex, int rowStartIndex, int rowEndIndex) { |
| mSelection.clear(); |
| for (int column = columnStartIndex; column <= columnEndIndex; column++) { |
| List<ItemData> items = mColumns.get(mXLimitsList.get(column).lowerLimit); |
| for (int row = rowStartIndex; row <= rowEndIndex; row++) { |
| int position = items.get(row).position; |
| mSelection.append(position, true); |
| if (isPossiblePositionNearestOrigin(column, columnStartIndex, columnEndIndex, |
| row, rowStartIndex, rowEndIndex)) { |
| // If this is the position nearest the origin, record it now so that it |
| // can be returned by endSelection() later. |
| mPositionNearestOrigin = position; |
| } |
| } |
| } |
| } |
| |
| /** |
| * @return Returns true if the position is the nearest to the origin, or, in the case of the |
| * lower-right corner, whether it is possible that the position is the nearest to the |
| * origin. See comment below for reasoning for this special case. |
| */ |
| private boolean isPossiblePositionNearestOrigin(int columnIndex, int columnStartIndex, |
| int columnEndIndex, int rowIndex, int rowStartIndex, int rowEndIndex) { |
| int corner = computeCornerNearestOrigin(); |
| switch (corner) { |
| case UPPER_LEFT: |
| return columnIndex == columnStartIndex && rowIndex == rowStartIndex; |
| case UPPER_RIGHT: |
| return columnIndex == columnEndIndex && rowIndex == rowStartIndex; |
| case LOWER_LEFT: |
| return columnIndex == columnStartIndex && rowIndex == rowEndIndex; |
| case LOWER_RIGHT: |
| // Note that in some cases, the last row will not have as many items as there |
| // are columns (e.g., if there are 4 items and 3 columns, the second row will |
| // only have one item in the first column). This function is invoked for each |
| // position from left to right, so return true for any position in the bottom |
| // row and only the right-most position in the bottom row will be recorded. |
| return rowIndex == rowEndIndex; |
| default: |
| throw new RuntimeException("Invalid corner type."); |
| } |
| } |
| |
| /** |
| * Listener for changes in which items have been band selected. |
| */ |
| static interface OnSelectionChangedListener { |
| public void onSelectionChanged(SparseBooleanArray updatedSelection); |
| } |
| |
| void addOnSelectionChangedListener(OnSelectionChangedListener listener) { |
| mOnSelectionChangedListeners.add(listener); |
| } |
| |
| void removeOnSelectionChangedListener(OnSelectionChangedListener listener) { |
| mOnSelectionChangedListeners.remove(listener); |
| } |
| |
| /** |
| * Metadata for an item in the view, consisting of the adapter position and the offset from the |
| * top of the view (in pixels). Stored in the mColumns map to model the item grid. |
| */ |
| private class ItemData implements Comparable<ItemData> { |
| int position; |
| int offset; |
| |
| ItemData(int position, int offset) { |
| this.position = position; |
| this.offset = offset; |
| } |
| |
| @Override |
| public int compareTo(ItemData other) { |
| // The list of columns is sorted via the offset from the top, so PositionMetadata |
| // objects with lower y-values are befor those with higher y-values. |
| return offset - other.offset; |
| } |
| } |
| |
| /** |
| * Limits of a view item. For example, if an item's left side is at x-value 5 and its right side |
| * is at x-value 10, the limits would be from 5 to 10. Used to record the left- and right sides |
| * of item columns and the top- and bottom sides of item rows so that it can be determined |
| * whether the pointer is located within the bounds of an item. |
| */ |
| private class Limits implements Comparable<Limits> { |
| int lowerLimit; |
| int upperLimit; |
| |
| Limits(int lowerLimit, int upperLimit) { |
| this.lowerLimit = lowerLimit; |
| this.upperLimit = upperLimit; |
| } |
| |
| @Override |
| public int compareTo(Limits other) { |
| return lowerLimit - other.lowerLimit; |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (!(other instanceof Limits)) { |
| return false; |
| } |
| |
| return ((Limits) other).lowerLimit == lowerLimit && |
| ((Limits) other).upperLimit == upperLimit; |
| } |
| } |
| |
| /** |
| * The location of a coordinate relative to items. This class represents a general area of the |
| * view as it relates to band selection rather than an explicit point. For example, two |
| * different points within an item are considered to have the same "location" because band |
| * selection originating within the item would select the same items no matter which point |
| * was used. Same goes for points between items as well as those at the very beginning or end |
| * of the view. |
| * |
| * Tracking a coordinate (e.g., an x-value) as a CoordinateLocation instead of as an int has the |
| * advantage of tying the value to the Limits of items along that axis. This allows easy |
| * selection of items within those Limits as opposed to a search through every item to see if a |
| * given coordinate value falls within those Limits. |
| */ |
| private class RelativeCoordinate |
| implements Comparable<RelativeCoordinate> { |
| /** |
| * Location describing points after the last known item. |
| */ |
| static final int AFTER_LAST_ITEM = 0; |
| |
| /** |
| * Location describing points before the first known item. |
| */ |
| static final int BEFORE_FIRST_ITEM = 1; |
| |
| /** |
| * Location describing points between two items. |
| */ |
| static final int BETWEEN_TWO_ITEMS = 2; |
| |
| /** |
| * Location describing points within the limits of one item. |
| */ |
| static final int WITHIN_LIMITS = 3; |
| |
| /** |
| * The type of this coordinate, which is one of AFTER_LAST_ITEM, BEFORE_FIRST_ITEM, |
| * BETWEEN_TWO_ITEMS, or WITHIN_LIMITS. |
| */ |
| final int type; |
| |
| /** |
| * The limits before the coordinate; only populated when type == WITHIN_LIMITS or type == |
| * BETWEEN_TWO_ITEMS. |
| */ |
| Limits limitsBeforeCoordinate; |
| |
| /** |
| * The limits after the coordinate; only populated when type == BETWEEN_TWO_ITEMS. |
| */ |
| Limits limitsAfterCoordinate; |
| |
| // Limits of the first known item; only populated when type == BEFORE_FIRST_ITEM. |
| Limits mFirstKnownItem; |
| // Limits of the last known item; only populated when type == AFTER_LAST_ITEM. |
| Limits mLastKnownItem; |
| |
| /** |
| * @param limitsList The sorted limits list for the coordinate type. If this |
| * CoordinateLocation is an x-value, mXLimitsList should be passed; otherwise, |
| * mYLimitsList should be pased. |
| * @param value The coordinate value. |
| */ |
| RelativeCoordinate(List<Limits> limitsList, int value) { |
| Limits dummyLimits = new Limits(value, value); |
| int index = Collections.binarySearch(limitsList, dummyLimits); |
| |
| if (index >= 0) { |
| this.type = WITHIN_LIMITS; |
| this.limitsBeforeCoordinate = limitsList.get(index); |
| } else if (~index == 0) { |
| this.type = BEFORE_FIRST_ITEM; |
| this.mFirstKnownItem = limitsList.get(0); |
| } else if (~index == limitsList.size()) { |
| Limits lastLimits = limitsList.get(limitsList.size() - 1); |
| if (lastLimits.lowerLimit <= value && value <= lastLimits.upperLimit) { |
| this.type = WITHIN_LIMITS; |
| this.limitsBeforeCoordinate = lastLimits; |
| } else { |
| this.type = AFTER_LAST_ITEM; |
| this.mLastKnownItem = lastLimits; |
| } |
| } else { |
| Limits limitsBeforeIndex = limitsList.get(~index - 1); |
| if (limitsBeforeIndex.lowerLimit <= value && value <= limitsBeforeIndex.upperLimit) { |
| this.type = WITHIN_LIMITS; |
| this.limitsBeforeCoordinate = limitsList.get(~index - 1); |
| } else { |
| this.type = BETWEEN_TWO_ITEMS; |
| this.limitsBeforeCoordinate = limitsList.get(~index - 1); |
| this.limitsAfterCoordinate = limitsList.get(~index); |
| } |
| } |
| } |
| |
| int toComparisonValue() { |
| if (type == BEFORE_FIRST_ITEM) { |
| return mFirstKnownItem.lowerLimit - 1; |
| } else if (type == AFTER_LAST_ITEM) { |
| return mLastKnownItem.upperLimit + 1; |
| } else if (type == BETWEEN_TWO_ITEMS) { |
| return limitsBeforeCoordinate.upperLimit + 1; |
| } else { |
| return limitsBeforeCoordinate.lowerLimit; |
| } |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (!(other instanceof RelativeCoordinate)) { |
| return false; |
| } |
| |
| RelativeCoordinate otherCoordinate = (RelativeCoordinate) other; |
| return toComparisonValue() == otherCoordinate.toComparisonValue(); |
| } |
| |
| @Override |
| public int compareTo(RelativeCoordinate other) { |
| return toComparisonValue() - other.toComparisonValue(); |
| } |
| } |
| |
| /** |
| * The location of a point relative to the Limits of nearby items; consists of both an x- and |
| * y-RelativeCoordinateLocation. |
| */ |
| private class RelativePoint { |
| final RelativeCoordinate xLocation; |
| final RelativeCoordinate yLocation; |
| |
| RelativePoint(Point point) { |
| this.xLocation = new RelativeCoordinate(mXLimitsList, point.x); |
| this.yLocation = new RelativeCoordinate(mYLimitsList, point.y); |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (!(other instanceof RelativePoint)) { |
| return false; |
| } |
| |
| RelativePoint otherPoint = (RelativePoint) other; |
| return xLocation.equals(otherPoint.xLocation) && yLocation.equals(otherPoint.yLocation); |
| } |
| } |
| |
| /** |
| * Generates a rectangle which contains the items selected by the pointer and origin. |
| * @return The rectangle, or null if no items were selected. |
| */ |
| private Rect computeBounds() { |
| Rect rect = new Rect(); |
| rect.left = getCoordinateValue( |
| min(mRelativeOrigin.xLocation, mRelativePointer.xLocation), |
| mXLimitsList, |
| true); |
| rect.right = getCoordinateValue( |
| max(mRelativeOrigin.xLocation, mRelativePointer.xLocation), |
| mXLimitsList, |
| false); |
| rect.top = getCoordinateValue( |
| min(mRelativeOrigin.yLocation, mRelativePointer.yLocation), |
| mYLimitsList, |
| true); |
| rect.bottom = getCoordinateValue( |
| max(mRelativeOrigin.yLocation, mRelativePointer.yLocation), |
| mYLimitsList, |
| false); |
| return rect; |
| } |
| |
| /** |
| * Computes the corner of the selection nearest the origin. |
| * @return |
| */ |
| private int computeCornerNearestOrigin() { |
| int cornerValue = 0; |
| |
| if (mRelativeOrigin.yLocation == |
| min(mRelativeOrigin.yLocation, mRelativePointer.yLocation)) { |
| cornerValue |= UPPER; |
| } else { |
| cornerValue |= LOWER; |
| } |
| |
| if (mRelativeOrigin.xLocation == |
| min(mRelativeOrigin.xLocation, mRelativePointer.xLocation)) { |
| cornerValue |= LEFT; |
| } else { |
| cornerValue |= RIGHT; |
| } |
| |
| return cornerValue; |
| } |
| |
| private RelativeCoordinate min(RelativeCoordinate first, RelativeCoordinate second) { |
| return first.compareTo(second) < 0 ? first : second; |
| } |
| |
| private RelativeCoordinate max(RelativeCoordinate first, RelativeCoordinate second) { |
| return first.compareTo(second) > 0 ? first : second; |
| } |
| |
| /** |
| * @return The absolute coordinate (i.e., the x- or y-value) of the given relative |
| * coordinate. |
| */ |
| private int getCoordinateValue(RelativeCoordinate coordinate, |
| List<Limits> limitsList, boolean isStartOfRange) { |
| switch (coordinate.type) { |
| case RelativeCoordinate.BEFORE_FIRST_ITEM: |
| return limitsList.get(0).lowerLimit; |
| case RelativeCoordinate.AFTER_LAST_ITEM: |
| return limitsList.get(limitsList.size() - 1).upperLimit; |
| case RelativeCoordinate.BETWEEN_TWO_ITEMS: |
| if (isStartOfRange) { |
| return coordinate.limitsAfterCoordinate.lowerLimit; |
| } else { |
| return coordinate.limitsBeforeCoordinate.upperLimit; |
| } |
| case RelativeCoordinate.WITHIN_LIMITS: |
| return coordinate.limitsBeforeCoordinate.lowerLimit; |
| } |
| |
| throw new RuntimeException("Invalid coordinate value."); |
| } |
| |
| private boolean areItemsCoveredBySelection( |
| RelativePoint first, RelativePoint second) { |
| return doesCoordinateLocationCoverItems(first.xLocation, second.xLocation) && |
| doesCoordinateLocationCoverItems(first.yLocation, second.yLocation); |
| } |
| |
| private boolean doesCoordinateLocationCoverItems( |
| RelativeCoordinate pointerCoordinate, |
| RelativeCoordinate originCoordinate) { |
| if (pointerCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM && |
| originCoordinate.type == RelativeCoordinate.BEFORE_FIRST_ITEM) { |
| return false; |
| } |
| |
| if (pointerCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM && |
| originCoordinate.type == RelativeCoordinate.AFTER_LAST_ITEM) { |
| return false; |
| } |
| |
| if (pointerCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS && |
| originCoordinate.type == RelativeCoordinate.BETWEEN_TWO_ITEMS && |
| pointerCoordinate.limitsBeforeCoordinate.equals( |
| originCoordinate.limitsBeforeCoordinate) && |
| pointerCoordinate.limitsAfterCoordinate.equals( |
| originCoordinate.limitsAfterCoordinate)) { |
| return false; |
| } |
| |
| return true; |
| } |
| } |
| } |