| /* |
| * Copyright (C) 2010 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.launcher2; |
| |
| import java.util.ArrayList; |
| import java.util.Arrays; |
| |
| import android.content.Context; |
| import android.graphics.Canvas; |
| import android.graphics.Rect; |
| import android.os.Parcel; |
| import android.os.Parcelable; |
| import android.util.AttributeSet; |
| import android.view.MotionEvent; |
| import android.view.VelocityTracker; |
| import android.view.View; |
| import android.view.ViewConfiguration; |
| import android.view.ViewGroup; |
| import android.view.ViewParent; |
| import android.view.animation.Animation; |
| import android.view.animation.Animation.AnimationListener; |
| import android.view.animation.AnimationUtils; |
| import android.widget.Scroller; |
| |
| import com.android.launcher.R; |
| |
| /** |
| * An abstraction of the original Workspace which supports browsing through a |
| * sequential list of "pages" (or PagedViewCellLayouts). |
| */ |
| public abstract class PagedView extends ViewGroup { |
| private static final String TAG = "PagedView"; |
| private static final int INVALID_PAGE = -1; |
| |
| // the velocity at which a fling gesture will cause us to snap to the next page |
| private static final int SNAP_VELOCITY = 500; |
| |
| // the min drag distance for a fling to register, to prevent random page shifts |
| private static final int MIN_LENGTH_FOR_FLING = 50; |
| |
| private boolean mFirstLayout = true; |
| |
| private int mCurrentPage; |
| private int mNextPage = INVALID_PAGE; |
| private Scroller mScroller; |
| private VelocityTracker mVelocityTracker; |
| |
| private float mDownMotionX; |
| private float mLastMotionX; |
| private float mLastMotionY; |
| |
| private final static int TOUCH_STATE_REST = 0; |
| private final static int TOUCH_STATE_SCROLLING = 1; |
| private final static int TOUCH_STATE_PREV_PAGE = 2; |
| private final static int TOUCH_STATE_NEXT_PAGE = 3; |
| |
| private int mTouchState = TOUCH_STATE_REST; |
| |
| private OnLongClickListener mLongClickListener; |
| |
| private boolean mAllowLongPress = true; |
| |
| private int mTouchSlop; |
| private int mPagingTouchSlop; |
| private int mMaximumVelocity; |
| |
| private static final int INVALID_POINTER = -1; |
| |
| private int mActivePointerId = INVALID_POINTER; |
| |
| private PageSwitchListener mPageSwitchListener; |
| |
| private ArrayList<Boolean> mDirtyPageContent; |
| private boolean mDirtyPageAlpha; |
| |
| public interface PageSwitchListener { |
| void onPageSwitch(View newPage, int newPageIndex); |
| } |
| |
| public PagedView(Context context) { |
| this(context, null); |
| } |
| |
| public PagedView(Context context, AttributeSet attrs) { |
| this(context, attrs, 0); |
| } |
| |
| public PagedView(Context context, AttributeSet attrs, int defStyle) { |
| super(context, attrs, defStyle); |
| |
| setHapticFeedbackEnabled(false); |
| initWorkspace(); |
| } |
| |
| /** |
| * Initializes various states for this workspace. |
| */ |
| private void initWorkspace() { |
| mDirtyPageContent = new ArrayList<Boolean>(); |
| mDirtyPageContent.ensureCapacity(32); |
| mScroller = new Scroller(getContext()); |
| mCurrentPage = 0; |
| |
| final ViewConfiguration configuration = ViewConfiguration.get(getContext()); |
| mTouchSlop = configuration.getScaledTouchSlop(); |
| mPagingTouchSlop = configuration.getScaledPagingTouchSlop(); |
| mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); |
| } |
| |
| public void setPageSwitchListener(PageSwitchListener pageSwitchListener) { |
| mPageSwitchListener = pageSwitchListener; |
| if (mPageSwitchListener != null) { |
| mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); |
| } |
| } |
| |
| /** |
| * Returns the index of the currently displayed page. |
| * |
| * @return The index of the currently displayed page. |
| */ |
| int getCurrentPage() { |
| return mCurrentPage; |
| } |
| |
| int getPageCount() { |
| return getChildCount(); |
| } |
| |
| View getPageAt(int index) { |
| return getChildAt(index); |
| } |
| |
| int getScrollWidth() { |
| return getWidth(); |
| } |
| |
| /** |
| * Sets the current page. |
| */ |
| void setCurrentPage(int currentPage) { |
| if (!mScroller.isFinished()) mScroller.abortAnimation(); |
| if (getChildCount() == 0) return; |
| |
| mCurrentPage = Math.max(0, Math.min(currentPage, getPageCount() - 1)); |
| scrollTo(getChildOffset(mCurrentPage) - getRelativeChildOffset(mCurrentPage), 0); |
| |
| invalidate(); |
| notifyPageSwitchListener(); |
| } |
| |
| private void notifyPageSwitchListener() { |
| if (mPageSwitchListener != null) { |
| mPageSwitchListener.onPageSwitch(getPageAt(mCurrentPage), mCurrentPage); |
| } |
| } |
| |
| /** |
| * Registers the specified listener on each page contained in this workspace. |
| * |
| * @param l The listener used to respond to long clicks. |
| */ |
| @Override |
| public void setOnLongClickListener(OnLongClickListener l) { |
| mLongClickListener = l; |
| final int count = getPageCount(); |
| for (int i = 0; i < count; i++) { |
| getPageAt(i).setOnLongClickListener(l); |
| } |
| } |
| |
| @Override |
| public void computeScroll() { |
| if (mScroller.computeScrollOffset()) { |
| scrollTo(mScroller.getCurrX(), mScroller.getCurrY()); |
| postInvalidate(); |
| } else if (mNextPage != INVALID_PAGE) { |
| mCurrentPage = Math.max(0, Math.min(mNextPage, getPageCount() - 1)); |
| notifyPageSwitchListener(); |
| mNextPage = INVALID_PAGE; |
| } |
| } |
| |
| @Override |
| protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
| final int widthMode = MeasureSpec.getMode(widthMeasureSpec); |
| final int widthSize = MeasureSpec.getSize(widthMeasureSpec); |
| if (widthMode != MeasureSpec.EXACTLY) { |
| throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); |
| } |
| |
| final int heightMode = MeasureSpec.getMode(heightMeasureSpec); |
| final int heightSize = MeasureSpec.getSize(heightMeasureSpec); |
| if (heightMode != MeasureSpec.EXACTLY) { |
| throw new IllegalStateException("Workspace can only be used in EXACTLY mode."); |
| } |
| |
| // The children are given the same width and height as the workspace |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; i++) { |
| getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec); |
| } |
| |
| setMeasuredDimension(widthSize, heightSize); |
| |
| if (mFirstLayout) { |
| setHorizontalScrollBarEnabled(false); |
| scrollTo(mCurrentPage * widthSize, 0); |
| setHorizontalScrollBarEnabled(true); |
| mFirstLayout = false; |
| } |
| } |
| |
| @Override |
| protected void onLayout(boolean changed, int left, int top, int right, int bottom) { |
| final int childCount = getChildCount(); |
| int childLeft = 0; |
| if (childCount > 0) { |
| childLeft = (getMeasuredWidth() - getChildAt(0).getMeasuredWidth()) / 2; |
| } |
| |
| for (int i = 0; i < childCount; i++) { |
| final View child = getChildAt(i); |
| if (child.getVisibility() != View.GONE) { |
| final int childWidth = child.getMeasuredWidth(); |
| child.layout(childLeft, 0, childLeft + childWidth, child.getMeasuredHeight()); |
| childLeft += childWidth; |
| } |
| } |
| } |
| |
| @Override |
| protected void dispatchDraw(Canvas canvas) { |
| if (mDirtyPageAlpha || (mTouchState == TOUCH_STATE_SCROLLING) || !mScroller.isFinished()) { |
| int screenCenter = mScrollX + (getMeasuredWidth() / 2); |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; ++i) { |
| PagedViewCellLayout layout = (PagedViewCellLayout) getChildAt(i); |
| int childWidth = layout.getMeasuredWidth(); |
| int halfChildWidth = (childWidth / 2); |
| int childCenter = getChildOffset(i) + halfChildWidth; |
| int distanceFromScreenCenter = Math.abs(childCenter - screenCenter); |
| float alpha = 0.0f; |
| if (distanceFromScreenCenter < halfChildWidth) { |
| alpha = 1.0f; |
| } else if (distanceFromScreenCenter > childWidth) { |
| alpha = 0.0f; |
| } else { |
| float dimAlpha = (float) (distanceFromScreenCenter - halfChildWidth) / halfChildWidth; |
| dimAlpha = Math.max(0.0f, Math.min(1.0f, (dimAlpha * dimAlpha))); |
| alpha = 1.0f - dimAlpha; |
| } |
| if (Float.compare(alpha, layout.getAlpha()) != 0) { |
| layout.setAlpha(alpha); |
| } |
| } |
| mDirtyPageAlpha = false; |
| } |
| super.dispatchDraw(canvas); |
| } |
| |
| @Override |
| public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) { |
| int page = indexOfChild(child); |
| if (page != mCurrentPage || !mScroller.isFinished()) { |
| snapToPage(page); |
| return true; |
| } |
| return false; |
| } |
| |
| @Override |
| protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) { |
| int focusablePage; |
| if (mNextPage != INVALID_PAGE) { |
| focusablePage = mNextPage; |
| } else { |
| focusablePage = mCurrentPage; |
| } |
| View v = getPageAt(focusablePage); |
| if (v != null) { |
| v.requestFocus(direction, previouslyFocusedRect); |
| } |
| return false; |
| } |
| |
| @Override |
| public boolean dispatchUnhandledMove(View focused, int direction) { |
| if (direction == View.FOCUS_LEFT) { |
| if (getCurrentPage() > 0) { |
| snapToPage(getCurrentPage() - 1); |
| return true; |
| } |
| } else if (direction == View.FOCUS_RIGHT) { |
| if (getCurrentPage() < getPageCount() - 1) { |
| snapToPage(getCurrentPage() + 1); |
| return true; |
| } |
| } |
| return super.dispatchUnhandledMove(focused, direction); |
| } |
| |
| @Override |
| public void addFocusables(ArrayList<View> views, int direction, int focusableMode) { |
| if (mCurrentPage >= 0 && mCurrentPage < getPageCount()) { |
| getPageAt(mCurrentPage).addFocusables(views, direction); |
| } |
| if (direction == View.FOCUS_LEFT) { |
| if (mCurrentPage > 0) { |
| getPageAt(mCurrentPage - 1).addFocusables(views, direction); |
| } |
| } else if (direction == View.FOCUS_RIGHT){ |
| if (mCurrentPage < getPageCount() - 1) { |
| getPageAt(mCurrentPage + 1).addFocusables(views, direction); |
| } |
| } |
| } |
| |
| /** |
| * If one of our descendant views decides that it could be focused now, only |
| * pass that along if it's on the current page. |
| * |
| * This happens when live folders requery, and if they're off page, they |
| * end up calling requestFocus, which pulls it on page. |
| */ |
| @Override |
| public void focusableViewAvailable(View focused) { |
| View current = getPageAt(mCurrentPage); |
| View v = focused; |
| while (true) { |
| if (v == current) { |
| super.focusableViewAvailable(focused); |
| return; |
| } |
| if (v == this) { |
| return; |
| } |
| ViewParent parent = v.getParent(); |
| if (parent instanceof View) { |
| v = (View)v.getParent(); |
| } else { |
| return; |
| } |
| } |
| } |
| |
| /** |
| * {@inheritDoc} |
| */ |
| @Override |
| public void requestDisallowInterceptTouchEvent(boolean disallowIntercept) { |
| if (disallowIntercept) { |
| // We need to make sure to cancel our long press if |
| // a scrollable widget takes over touch events |
| final View currentPage = getChildAt(mCurrentPage); |
| currentPage.cancelLongPress(); |
| } |
| super.requestDisallowInterceptTouchEvent(disallowIntercept); |
| } |
| |
| @Override |
| public boolean onInterceptTouchEvent(MotionEvent ev) { |
| /* |
| * This method JUST determines whether we want to intercept the motion. |
| * If we return true, onTouchEvent will be called and we do the actual |
| * scrolling there. |
| */ |
| |
| /* |
| * Shortcut the most recurring case: the user is in the dragging |
| * state and he is moving his finger. We want to intercept this |
| * motion. |
| */ |
| final int action = ev.getAction(); |
| if ((action == MotionEvent.ACTION_MOVE) && |
| (mTouchState == TOUCH_STATE_SCROLLING)) { |
| return true; |
| } |
| |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_MOVE: { |
| /* |
| * mIsBeingDragged == false, otherwise the shortcut would have caught it. Check |
| * whether the user has moved far enough from his original down touch. |
| */ |
| determineScrollingStart(ev); |
| break; |
| } |
| |
| case MotionEvent.ACTION_DOWN: { |
| final float x = ev.getX(); |
| final float y = ev.getY(); |
| // Remember location of down touch |
| mDownMotionX = x; |
| mLastMotionX = x; |
| mLastMotionY = y; |
| mActivePointerId = ev.getPointerId(0); |
| mAllowLongPress = true; |
| |
| /* |
| * If being flinged and user touches the screen, initiate drag; |
| * otherwise don't. mScroller.isFinished should be false when |
| * being flinged. |
| */ |
| mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING; |
| |
| // check if this can be the beginning of a tap on the side of the pages |
| // to scroll the current page |
| if ((mTouchState != TOUCH_STATE_PREV_PAGE) && |
| (mTouchState != TOUCH_STATE_NEXT_PAGE)) { |
| if (getChildCount() > 0) { |
| int relativeChildLeft = getChildOffset(0); |
| int relativeChildRight = relativeChildLeft + getChildAt(0).getMeasuredWidth(); |
| if (x < relativeChildLeft) { |
| mTouchState = TOUCH_STATE_PREV_PAGE; |
| } else if (x > relativeChildRight) { |
| mTouchState = TOUCH_STATE_NEXT_PAGE; |
| } |
| } |
| } |
| break; |
| } |
| |
| case MotionEvent.ACTION_CANCEL: |
| case MotionEvent.ACTION_UP: |
| // Release the drag |
| mTouchState = TOUCH_STATE_REST; |
| mAllowLongPress = false; |
| mActivePointerId = INVALID_POINTER; |
| |
| break; |
| |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| |
| /* |
| * The only time we want to intercept motion events is if we are in the |
| * drag mode. |
| */ |
| return mTouchState != TOUCH_STATE_REST; |
| } |
| |
| protected void animateClickFeedback(View v, final Runnable r) { |
| // animate the view slightly to show click feedback running some logic after it is "pressed" |
| Animation anim = AnimationUtils.loadAnimation(getContext(), |
| R.anim.paged_view_click_feedback); |
| anim.setAnimationListener(new AnimationListener() { |
| @Override |
| public void onAnimationStart(Animation animation) {} |
| @Override |
| public void onAnimationRepeat(Animation animation) { |
| r.run(); |
| } |
| @Override |
| public void onAnimationEnd(Animation animation) {} |
| }); |
| v.startAnimation(anim); |
| } |
| |
| /* |
| * Determines if we should change the touch state to start scrolling after the |
| * user moves their touch point too far. |
| */ |
| private void determineScrollingStart(MotionEvent ev) { |
| /* |
| * Locally do absolute value. mLastMotionX is set to the y value |
| * of the down event. |
| */ |
| final int pointerIndex = ev.findPointerIndex(mActivePointerId); |
| final float x = ev.getX(pointerIndex); |
| final float y = ev.getY(pointerIndex); |
| final int xDiff = (int) Math.abs(x - mLastMotionX); |
| final int yDiff = (int) Math.abs(y - mLastMotionY); |
| |
| final int touchSlop = mTouchSlop; |
| boolean xPaged = xDiff > mPagingTouchSlop; |
| boolean xMoved = xDiff > touchSlop; |
| boolean yMoved = yDiff > touchSlop; |
| |
| if (xMoved || yMoved) { |
| if (xPaged) { |
| // Scroll if the user moved far enough along the X axis |
| mTouchState = TOUCH_STATE_SCROLLING; |
| mLastMotionX = x; |
| } |
| // Either way, cancel any pending longpress |
| if (mAllowLongPress) { |
| mAllowLongPress = false; |
| // Try canceling the long press. It could also have been scheduled |
| // by a distant descendant, so use the mAllowLongPress flag to block |
| // everything |
| final View currentPage = getPageAt(mCurrentPage); |
| currentPage.cancelLongPress(); |
| } |
| } |
| } |
| |
| @Override |
| public boolean onTouchEvent(MotionEvent ev) { |
| if (mVelocityTracker == null) { |
| mVelocityTracker = VelocityTracker.obtain(); |
| } |
| mVelocityTracker.addMovement(ev); |
| |
| final int action = ev.getAction(); |
| |
| switch (action & MotionEvent.ACTION_MASK) { |
| case MotionEvent.ACTION_DOWN: |
| /* |
| * If being flinged and user touches, stop the fling. isFinished |
| * will be false if being flinged. |
| */ |
| if (!mScroller.isFinished()) { |
| mScroller.abortAnimation(); |
| } |
| |
| // Remember where the motion event started |
| mDownMotionX = mLastMotionX = ev.getX(); |
| mActivePointerId = ev.getPointerId(0); |
| break; |
| |
| case MotionEvent.ACTION_MOVE: |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| // Scroll to follow the motion event |
| final int pointerIndex = ev.findPointerIndex(mActivePointerId); |
| final float x = ev.getX(pointerIndex); |
| final int deltaX = (int) (mLastMotionX - x); |
| mLastMotionX = x; |
| |
| int sx = getScrollX(); |
| if (deltaX < 0) { |
| if (sx > 0) { |
| scrollBy(Math.max(-sx, deltaX), 0); |
| } |
| } else if (deltaX > 0) { |
| final int lastChildIndex = getChildCount() - 1; |
| final int availableToScroll = getChildOffset(lastChildIndex) - |
| getRelativeChildOffset(lastChildIndex) - sx; |
| if (availableToScroll > 0) { |
| scrollBy(Math.min(availableToScroll, deltaX), 0); |
| } |
| } else { |
| awakenScrollBars(); |
| } |
| } else if ((mTouchState == TOUCH_STATE_PREV_PAGE) || |
| (mTouchState == TOUCH_STATE_NEXT_PAGE)) { |
| determineScrollingStart(ev); |
| } |
| break; |
| |
| case MotionEvent.ACTION_UP: |
| if (mTouchState == TOUCH_STATE_SCROLLING) { |
| final int activePointerId = mActivePointerId; |
| final int pointerIndex = ev.findPointerIndex(activePointerId); |
| final float x = ev.getX(pointerIndex); |
| final VelocityTracker velocityTracker = mVelocityTracker; |
| velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); |
| int velocityX = (int) velocityTracker.getXVelocity(activePointerId); |
| boolean isfling = Math.abs(mDownMotionX - x) > MIN_LENGTH_FOR_FLING; |
| |
| if (isfling && velocityX > SNAP_VELOCITY && mCurrentPage > 0) { |
| snapToPage(mCurrentPage - 1); |
| } else if (isfling && velocityX < -SNAP_VELOCITY && |
| mCurrentPage < getChildCount() - 1) { |
| snapToPage(mCurrentPage + 1); |
| } else { |
| snapToDestination(); |
| } |
| |
| if (mVelocityTracker != null) { |
| mVelocityTracker.recycle(); |
| mVelocityTracker = null; |
| } |
| } else if (mTouchState == TOUCH_STATE_PREV_PAGE) { |
| // at this point we have not moved beyond the touch slop |
| // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so |
| // we can just page |
| int nextPage = Math.max(0, mCurrentPage - 1); |
| if (nextPage != mCurrentPage) { |
| snapToPage(nextPage); |
| } else { |
| snapToDestination(); |
| } |
| } else if (mTouchState == TOUCH_STATE_NEXT_PAGE) { |
| // at this point we have not moved beyond the touch slop |
| // (otherwise mTouchState would be TOUCH_STATE_SCROLLING), so |
| // we can just page |
| int nextPage = Math.min(getChildCount() - 1, mCurrentPage + 1); |
| if (nextPage != mCurrentPage) { |
| snapToPage(nextPage); |
| } else { |
| snapToDestination(); |
| } |
| } |
| mTouchState = TOUCH_STATE_REST; |
| mActivePointerId = INVALID_POINTER; |
| break; |
| |
| case MotionEvent.ACTION_CANCEL: |
| mTouchState = TOUCH_STATE_REST; |
| mActivePointerId = INVALID_POINTER; |
| break; |
| |
| case MotionEvent.ACTION_POINTER_UP: |
| onSecondaryPointerUp(ev); |
| break; |
| } |
| |
| return true; |
| } |
| |
| private void onSecondaryPointerUp(MotionEvent ev) { |
| final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> |
| MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
| final int pointerId = ev.getPointerId(pointerIndex); |
| if (pointerId == mActivePointerId) { |
| // This was our active pointer going up. Choose a new |
| // active pointer and adjust accordingly. |
| // TODO: Make this decision more intelligent. |
| final int newPointerIndex = pointerIndex == 0 ? 1 : 0; |
| mLastMotionX = mDownMotionX = ev.getX(newPointerIndex); |
| mLastMotionY = ev.getY(newPointerIndex); |
| mActivePointerId = ev.getPointerId(newPointerIndex); |
| if (mVelocityTracker != null) { |
| mVelocityTracker.clear(); |
| } |
| } |
| } |
| |
| @Override |
| public void requestChildFocus(View child, View focused) { |
| super.requestChildFocus(child, focused); |
| int page = indexOfChild(child); |
| if (page >= 0 && !isInTouchMode()) { |
| snapToPage(page); |
| } |
| } |
| |
| protected int getRelativeChildOffset(int index) { |
| return (getMeasuredWidth() - getChildAt(index).getMeasuredWidth()) / 2; |
| } |
| |
| protected int getChildOffset(int index) { |
| if (getChildCount() == 0) |
| return 0; |
| |
| int offset = getRelativeChildOffset(0); |
| for (int i = 0; i < index; ++i) { |
| offset += getChildAt(i).getMeasuredWidth(); |
| } |
| return offset; |
| } |
| |
| protected void snapToDestination() { |
| int minDistanceFromScreenCenter = getMeasuredWidth(); |
| int minDistanceFromScreenCenterIndex = -1; |
| int screenCenter = mScrollX + (getMeasuredWidth() / 2); |
| final int childCount = getChildCount(); |
| for (int i = 0; i < childCount; ++i) { |
| PagedViewCellLayout layout = (PagedViewCellLayout) getChildAt(i); |
| int childWidth = layout.getMeasuredWidth(); |
| int halfChildWidth = (childWidth / 2); |
| int childCenter = getChildOffset(i) + halfChildWidth; |
| int distanceFromScreenCenter = Math.abs(childCenter - screenCenter); |
| if (distanceFromScreenCenter < minDistanceFromScreenCenter) { |
| minDistanceFromScreenCenter = distanceFromScreenCenter; |
| minDistanceFromScreenCenterIndex = i; |
| } |
| } |
| snapToPage(minDistanceFromScreenCenterIndex, 1000); |
| } |
| |
| void snapToPage(int whichPage) { |
| snapToPage(whichPage, 1000); |
| } |
| |
| void snapToPage(int whichPage, int duration) { |
| whichPage = Math.max(0, Math.min(whichPage, getPageCount() - 1)); |
| |
| mNextPage = whichPage; |
| |
| int newX = getChildOffset(whichPage) - getRelativeChildOffset(whichPage); |
| final int sX = getScrollX(); |
| final int delta = newX - sX; |
| awakenScrollBars(duration); |
| if (duration == 0) { |
| duration = Math.abs(delta); |
| } |
| |
| if (!mScroller.isFinished()) mScroller.abortAnimation(); |
| mScroller.startScroll(sX, 0, delta, 0, duration); |
| |
| // only load some associated pages |
| loadAssociatedPages(mNextPage); |
| |
| invalidate(); |
| } |
| |
| @Override |
| protected Parcelable onSaveInstanceState() { |
| final SavedState state = new SavedState(super.onSaveInstanceState()); |
| state.currentPage = mCurrentPage; |
| return state; |
| } |
| |
| @Override |
| protected void onRestoreInstanceState(Parcelable state) { |
| SavedState savedState = (SavedState) state; |
| super.onRestoreInstanceState(savedState.getSuperState()); |
| if (savedState.currentPage != -1) { |
| mCurrentPage = savedState.currentPage; |
| } |
| } |
| |
| public void scrollLeft() { |
| if (mScroller.isFinished()) { |
| if (mCurrentPage > 0) snapToPage(mCurrentPage - 1); |
| } else { |
| if (mNextPage > 0) snapToPage(mNextPage - 1); |
| } |
| } |
| |
| public void scrollRight() { |
| if (mScroller.isFinished()) { |
| if (mCurrentPage < getChildCount() -1) snapToPage(mCurrentPage + 1); |
| } else { |
| if (mNextPage < getChildCount() -1) snapToPage(mNextPage + 1); |
| } |
| } |
| |
| public int getPageForView(View v) { |
| int result = -1; |
| if (v != null) { |
| ViewParent vp = v.getParent(); |
| int count = getChildCount(); |
| for (int i = 0; i < count; i++) { |
| if (vp == getChildAt(i)) { |
| return i; |
| } |
| } |
| } |
| return result; |
| } |
| |
| /** |
| * @return True is long presses are still allowed for the current touch |
| */ |
| public boolean allowLongPress() { |
| return mAllowLongPress; |
| } |
| |
| public static class SavedState extends BaseSavedState { |
| int currentPage = -1; |
| |
| SavedState(Parcelable superState) { |
| super(superState); |
| } |
| |
| private SavedState(Parcel in) { |
| super(in); |
| currentPage = in.readInt(); |
| } |
| |
| @Override |
| public void writeToParcel(Parcel out, int flags) { |
| super.writeToParcel(out, flags); |
| out.writeInt(currentPage); |
| } |
| |
| public static final Parcelable.Creator<SavedState> CREATOR = |
| new Parcelable.Creator<SavedState>() { |
| public SavedState createFromParcel(Parcel in) { |
| return new SavedState(in); |
| } |
| |
| public SavedState[] newArray(int size) { |
| return new SavedState[size]; |
| } |
| }; |
| } |
| |
| public void loadAssociatedPages(int page) { |
| final int count = getChildCount(); |
| if (page < count) { |
| int lowerPageBound = Math.max(0, page - 1); |
| int upperPageBound = Math.min(page + 1, count - 1); |
| for (int i = 0; i < count; ++i) { |
| final PagedViewCellLayout layout = (PagedViewCellLayout) getChildAt(i); |
| final int childCount = layout.getChildCount(); |
| if (lowerPageBound <= i && i <= upperPageBound) { |
| if (mDirtyPageContent.get(i)) { |
| syncPageItems(i); |
| mDirtyPageContent.set(i, false); |
| } |
| } else { |
| if (childCount > 0) { |
| layout.removeAllViews(); |
| } |
| mDirtyPageContent.set(i, true); |
| } |
| } |
| } |
| } |
| |
| /** |
| * This method is called ONLY to synchronize the number of pages that the paged view has. |
| * To actually fill the pages with information, implement syncPageItems() below. It is |
| * guaranteed that syncPageItems() will be called for a particular page before it is shown, |
| * and therefore, individual page items do not need to be updated in this method. |
| */ |
| public abstract void syncPages(); |
| |
| /** |
| * This method is called to synchronize the items that are on a particular page. If views on |
| * the page can be reused, then they should be updated within this method. |
| */ |
| public abstract void syncPageItems(int page); |
| |
| public void invalidatePageData() { |
| // Update all the pages |
| syncPages(); |
| |
| // Mark each of the pages as dirty |
| final int count = getChildCount(); |
| mDirtyPageContent.clear(); |
| for (int i = 0; i < count; ++i) { |
| mDirtyPageContent.add(true); |
| } |
| |
| // Load any pages that are necessary for the current window of views |
| loadAssociatedPages(mCurrentPage); |
| mDirtyPageAlpha = true; |
| requestLayout(); |
| } |
| } |