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      1 /*
      2  * Copyright (C) 2019 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package android.view;
     18 
     19 import android.annotation.NonNull;
     20 import android.annotation.Nullable;
     21 import android.graphics.Rect;
     22 
     23 import com.android.internal.util.Preconditions;
     24 
     25 import java.lang.ref.WeakReference;
     26 import java.util.ArrayList;
     27 import java.util.Collections;
     28 import java.util.Iterator;
     29 import java.util.List;
     30 
     31 /**
     32  * Used by {@link ViewRootImpl} to track system gesture exclusion rects reported by views.
     33  */
     34 class GestureExclusionTracker {
     35     private boolean mGestureExclusionViewsChanged = false;
     36     private boolean mRootGestureExclusionRectsChanged = false;
     37     private List<Rect> mRootGestureExclusionRects = Collections.emptyList();
     38     private List<GestureExclusionViewInfo> mGestureExclusionViewInfos = new ArrayList<>();
     39     private List<Rect> mGestureExclusionRects = Collections.emptyList();
     40 
     41     public void updateRectsForView(@NonNull View view) {
     42         boolean found = false;
     43         final Iterator<GestureExclusionViewInfo> i = mGestureExclusionViewInfos.iterator();
     44         while (i.hasNext()) {
     45             final GestureExclusionViewInfo info = i.next();
     46             final View v = info.getView();
     47             if (v == null || !v.isAttachedToWindow()) {
     48                 mGestureExclusionViewsChanged = true;
     49                 i.remove();
     50                 continue;
     51             }
     52             if (v == view) {
     53                 found = true;
     54                 info.mDirty = true;
     55                 break;
     56             }
     57         }
     58         if (!found && view.isAttachedToWindow()) {
     59             mGestureExclusionViewInfos.add(new GestureExclusionViewInfo(view));
     60             mGestureExclusionViewsChanged = true;
     61         }
     62     }
     63 
     64     @Nullable
     65     public List<Rect> computeChangedRects() {
     66         boolean changed = mRootGestureExclusionRectsChanged;
     67         final Iterator<GestureExclusionViewInfo> i = mGestureExclusionViewInfos.iterator();
     68         final List<Rect> rects = new ArrayList<>(mRootGestureExclusionRects);
     69         while (i.hasNext()) {
     70             final GestureExclusionViewInfo info = i.next();
     71             switch (info.update()) {
     72                 case GestureExclusionViewInfo.CHANGED:
     73                     changed = true;
     74                     // Deliberate fall-through
     75                 case GestureExclusionViewInfo.UNCHANGED:
     76                     rects.addAll(info.mExclusionRects);
     77                     break;
     78                 case GestureExclusionViewInfo.GONE:
     79                     mGestureExclusionViewsChanged = true;
     80                     i.remove();
     81                     break;
     82             }
     83         }
     84         if (changed || mGestureExclusionViewsChanged) {
     85             mGestureExclusionViewsChanged = false;
     86             mRootGestureExclusionRectsChanged = false;
     87             if (!mGestureExclusionRects.equals(rects)) {
     88                 mGestureExclusionRects = rects;
     89                 return rects;
     90             }
     91         }
     92         return null;
     93     }
     94 
     95     public void setRootSystemGestureExclusionRects(@NonNull List<Rect> rects) {
     96         Preconditions.checkNotNull(rects, "rects must not be null");
     97         mRootGestureExclusionRects = rects;
     98         mRootGestureExclusionRectsChanged = true;
     99     }
    100 
    101     @NonNull
    102     public List<Rect> getRootSystemGestureExclusionRects() {
    103         return mRootGestureExclusionRects;
    104     }
    105 
    106     private static class GestureExclusionViewInfo {
    107         public static final int CHANGED = 0;
    108         public static final int UNCHANGED = 1;
    109         public static final int GONE = 2;
    110 
    111         private final WeakReference<View> mView;
    112         boolean mDirty = true;
    113         List<Rect> mExclusionRects = Collections.emptyList();
    114 
    115         GestureExclusionViewInfo(View view) {
    116             mView = new WeakReference<>(view);
    117         }
    118 
    119         public View getView() {
    120             return mView.get();
    121         }
    122 
    123         public int update() {
    124             final View excludedView = getView();
    125             if (excludedView == null || !excludedView.isAttachedToWindow()) return GONE;
    126             final List<Rect> localRects = excludedView.getSystemGestureExclusionRects();
    127             final List<Rect> newRects = new ArrayList<>(localRects.size());
    128             for (Rect src : localRects) {
    129                 Rect mappedRect = new Rect(src);
    130                 ViewParent p = excludedView.getParent();
    131                 if (p != null && p.getChildVisibleRect(excludedView, mappedRect, null)) {
    132                     newRects.add(mappedRect);
    133                 }
    134             }
    135 
    136             if (mExclusionRects.equals(localRects)) return UNCHANGED;
    137             mExclusionRects = newRects;
    138             return CHANGED;
    139         }
    140     }
    141 }
    142