| /* |
| * Copyright (C) 2013 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.example.android.supportv7.widget; |
| |
| import com.example.android.supportv7.Cheeses; |
| import com.example.android.supportv7.widget.adapter.SimpleStringAdapter; |
| import com.example.android.supportv7.widget.decorator.DividerItemDecoration; |
| |
| import android.app.Activity; |
| import android.content.Context; |
| import android.os.Bundle; |
| import android.support.v4.view.MenuItemCompat; |
| import android.support.v7.widget.RecyclerView; |
| import android.util.DisplayMetrics; |
| import android.view.Menu; |
| import android.view.MenuItem; |
| import android.view.View; |
| import android.view.ViewGroup; |
| |
| public class RecyclerViewActivity extends Activity { |
| |
| private static final String TAG = "RecyclerViewActivity"; |
| |
| private RecyclerView mRecyclerView; |
| |
| @Override |
| protected void onCreate(Bundle savedInstanceState) { |
| super.onCreate(savedInstanceState); |
| |
| final RecyclerView rv = new RecyclerView(this); |
| rv.setLayoutManager(new MyLayoutManager(this)); |
| rv.setHasFixedSize(true); |
| rv.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, |
| ViewGroup.LayoutParams.MATCH_PARENT)); |
| rv.setAdapter(new SimpleStringAdapter(this, Cheeses.sCheeseStrings) { |
| @Override |
| public SimpleStringAdapter.ViewHolder onCreateViewHolder(ViewGroup parent, |
| int viewType) { |
| final SimpleStringAdapter.ViewHolder vh = super |
| .onCreateViewHolder(parent, viewType); |
| vh.itemView.setOnClickListener(new View.OnClickListener() { |
| @Override |
| public void onClick(View v) { |
| final int pos = vh.getPosition(); |
| if (pos + 1 < getItemCount()) { |
| swap(pos, pos + 1); |
| } |
| } |
| }); |
| return vh; |
| } |
| }); |
| rv.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL_LIST)); |
| setContentView(rv); |
| mRecyclerView = rv; |
| } |
| |
| @Override |
| public boolean onCreateOptionsMenu(Menu menu) { |
| super.onCreateOptionsMenu(menu); |
| MenuItemCompat.setShowAsAction(menu.add("Layout"), MenuItemCompat.SHOW_AS_ACTION_IF_ROOM); |
| return true; |
| } |
| |
| @Override |
| public boolean onOptionsItemSelected(MenuItem item) { |
| mRecyclerView.requestLayout(); |
| return super.onOptionsItemSelected(item); |
| } |
| |
| private static final int SCROLL_DISTANCE = 80; // dp |
| |
| /** |
| * A basic ListView-style LayoutManager. |
| */ |
| class MyLayoutManager extends RecyclerView.LayoutManager { |
| |
| private static final String TAG = "MyLayoutManager"; |
| |
| private int mFirstPosition; |
| |
| private final int mScrollDistance; |
| |
| public MyLayoutManager(Context c) { |
| final DisplayMetrics dm = c.getResources().getDisplayMetrics(); |
| mScrollDistance = (int) (SCROLL_DISTANCE * dm.density + 0.5f); |
| } |
| |
| @Override |
| public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) { |
| final int parentBottom = getHeight() - getPaddingBottom(); |
| final View oldTopView = getChildCount() > 0 ? getChildAt(0) : null; |
| int oldTop = getPaddingTop(); |
| if (oldTopView != null) { |
| oldTop = oldTopView.getTop(); |
| } |
| |
| detachAndScrapAttachedViews(recycler); |
| |
| int top = oldTop; |
| int bottom; |
| final int left = getPaddingLeft(); |
| final int right = getWidth() - getPaddingRight(); |
| |
| final int count = state.getItemCount(); |
| for (int i = 0; mFirstPosition + i < count && top < parentBottom; i++, top = bottom) { |
| View v = recycler.getViewForPosition(mFirstPosition + i); |
| addView(v, i); |
| measureChildWithMargins(v, 0, 0); |
| bottom = top + getDecoratedMeasuredHeight(v); |
| layoutDecorated(v, left, top, right, bottom); |
| } |
| } |
| |
| @Override |
| public RecyclerView.LayoutParams generateDefaultLayoutParams() { |
| return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, |
| ViewGroup.LayoutParams.WRAP_CONTENT); |
| } |
| |
| @Override |
| public boolean canScrollVertically() { |
| return true; |
| } |
| |
| @Override |
| public int scrollVerticallyBy(int dy, RecyclerView.Recycler recycler, |
| RecyclerView.State state) { |
| if (getChildCount() == 0) { |
| return 0; |
| } |
| |
| int scrolled = 0; |
| final int left = getPaddingLeft(); |
| final int right = getWidth() - getPaddingRight(); |
| if (dy < 0) { |
| while (scrolled > dy) { |
| final View topView = getChildAt(0); |
| final int hangingTop = Math.max(-getDecoratedTop(topView), 0); |
| final int scrollBy = Math.min(scrolled - dy, hangingTop); |
| scrolled -= scrollBy; |
| offsetChildrenVertical(scrollBy); |
| if (mFirstPosition > 0 && scrolled > dy) { |
| mFirstPosition--; |
| View v = recycler.getViewForPosition(mFirstPosition); |
| addView(v, 0); |
| measureChildWithMargins(v, 0, 0); |
| final int bottom = getDecoratedTop(topView); |
| final int top = bottom - getDecoratedMeasuredHeight(v); |
| layoutDecorated(v, left, top, right, bottom); |
| } else { |
| break; |
| } |
| } |
| } else if (dy > 0) { |
| final int parentHeight = getHeight(); |
| while (scrolled < dy) { |
| final View bottomView = getChildAt(getChildCount() - 1); |
| final int hangingBottom = |
| Math.max(getDecoratedBottom(bottomView) - parentHeight, 0); |
| final int scrollBy = -Math.min(dy - scrolled, hangingBottom); |
| scrolled -= scrollBy; |
| offsetChildrenVertical(scrollBy); |
| if (scrolled < dy && state.getItemCount() > mFirstPosition + getChildCount()) { |
| View v = recycler.getViewForPosition(mFirstPosition + getChildCount()); |
| final int top = getDecoratedBottom(getChildAt(getChildCount() - 1)); |
| addView(v); |
| measureChildWithMargins(v, 0, 0); |
| final int bottom = top + getDecoratedMeasuredHeight(v); |
| layoutDecorated(v, left, top, right, bottom); |
| } else { |
| break; |
| } |
| } |
| } |
| recycleViewsOutOfBounds(recycler); |
| return scrolled; |
| } |
| |
| @Override |
| public View onFocusSearchFailed(View focused, int direction, |
| RecyclerView.Recycler recycler, RecyclerView.State state) { |
| final int oldCount = getChildCount(); |
| |
| if (oldCount == 0) { |
| return null; |
| } |
| |
| final int left = getPaddingLeft(); |
| final int right = getWidth() - getPaddingRight(); |
| |
| View toFocus = null; |
| int newViewsHeight = 0; |
| if (direction == View.FOCUS_UP || direction == View.FOCUS_BACKWARD) { |
| while (mFirstPosition > 0 && newViewsHeight < mScrollDistance) { |
| mFirstPosition--; |
| View v = recycler.getViewForPosition(mFirstPosition); |
| final int bottom = getDecoratedTop(getChildAt(0)); |
| addView(v, 0); |
| measureChildWithMargins(v, 0, 0); |
| final int top = bottom - getDecoratedMeasuredHeight(v); |
| layoutDecorated(v, left, top, right, bottom); |
| if (v.isFocusable()) { |
| toFocus = v; |
| break; |
| } |
| } |
| } |
| if (direction == View.FOCUS_DOWN || direction == View.FOCUS_FORWARD) { |
| while (mFirstPosition + getChildCount() < state.getItemCount() && |
| newViewsHeight < mScrollDistance) { |
| View v = recycler.getViewForPosition(mFirstPosition + getChildCount()); |
| final int top = getDecoratedBottom(getChildAt(getChildCount() - 1)); |
| addView(v); |
| measureChildWithMargins(v, 0, 0); |
| final int bottom = top + getDecoratedMeasuredHeight(v); |
| layoutDecorated(v, left, top, right, bottom); |
| if (v.isFocusable()) { |
| toFocus = v; |
| break; |
| } |
| } |
| } |
| |
| return toFocus; |
| } |
| |
| public void recycleViewsOutOfBounds(RecyclerView.Recycler recycler) { |
| final int childCount = getChildCount(); |
| final int parentWidth = getWidth(); |
| final int parentHeight = getHeight(); |
| boolean foundFirst = false; |
| int first = 0; |
| int last = 0; |
| for (int i = 0; i < childCount; i++) { |
| final View v = getChildAt(i); |
| if (v.hasFocus() || (getDecoratedRight(v) >= 0 && |
| getDecoratedLeft(v) <= parentWidth && |
| getDecoratedBottom(v) >= 0 && |
| getDecoratedTop(v) <= parentHeight)) { |
| if (!foundFirst) { |
| first = i; |
| foundFirst = true; |
| } |
| last = i; |
| } |
| } |
| for (int i = childCount - 1; i > last; i--) { |
| removeAndRecycleViewAt(i, recycler); |
| } |
| for (int i = first - 1; i >= 0; i--) { |
| removeAndRecycleViewAt(i, recycler); |
| } |
| if (getChildCount() == 0) { |
| mFirstPosition = 0; |
| } else { |
| mFirstPosition += first; |
| } |
| } |
| } |
| } |