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      1 /*
      2  * Copyright (C) 2015 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 com.android.launcher3.accessibility;
     18 
     19 import android.content.Context;
     20 import android.graphics.Rect;
     21 import android.os.Bundle;
     22 import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
     23 import android.support.v4.widget.ExploreByTouchHelper;
     24 import android.view.View;
     25 import android.view.View.OnClickListener;
     26 import android.view.accessibility.AccessibilityEvent;
     27 
     28 import com.android.launcher3.CellLayout;
     29 import com.android.launcher3.Launcher;
     30 import com.android.launcher3.R;
     31 
     32 import java.util.List;
     33 
     34 /**
     35  * Helper class to make drag-and-drop in a {@link CellLayout} accessible.
     36  */
     37 public abstract class DragAndDropAccessibilityDelegate extends ExploreByTouchHelper
     38         implements OnClickListener {
     39     protected static final int INVALID_POSITION = -1;
     40 
     41     private static final int[] sTempArray = new int[2];
     42 
     43     protected final CellLayout mView;
     44     protected final Context mContext;
     45     protected final LauncherAccessibilityDelegate mDelegate;
     46 
     47     private final Rect mTempRect = new Rect();
     48 
     49     public DragAndDropAccessibilityDelegate(CellLayout forView) {
     50         super(forView);
     51         mView = forView;
     52         mContext = mView.getContext();
     53         mDelegate = Launcher.getLauncher(mContext).getAccessibilityDelegate();
     54     }
     55 
     56     @Override
     57     protected int getVirtualViewAt(float x, float y) {
     58         if (x < 0 || y < 0 || x > mView.getMeasuredWidth() || y > mView.getMeasuredHeight()) {
     59             return INVALID_ID;
     60         }
     61         mView.pointToCellExact((int) x, (int) y, sTempArray);
     62 
     63         // Map cell to id
     64         int id = sTempArray[0] + sTempArray[1] * mView.getCountX();
     65         return intersectsValidDropTarget(id);
     66     }
     67 
     68     /**
     69      * @return the view id of the top left corner of a valid drop region or
     70      * {@link #INVALID_POSITION} if there is no such valid region.
     71      */
     72     protected abstract int intersectsValidDropTarget(int id);
     73 
     74     @Override
     75     protected void getVisibleVirtualViews(List<Integer> virtualViews) {
     76         // We create a virtual view for each cell of the grid
     77         // The cell ids correspond to cells in reading order.
     78         int nCells = mView.getCountX() * mView.getCountY();
     79 
     80         for (int i = 0; i < nCells; i++) {
     81             if (intersectsValidDropTarget(i) == i) {
     82                 virtualViews.add(i);
     83             }
     84         }
     85     }
     86 
     87     @Override
     88     protected boolean onPerformActionForVirtualView(int viewId, int action, Bundle args) {
     89         if (action == AccessibilityNodeInfoCompat.ACTION_CLICK && viewId != INVALID_ID) {
     90             String confirmation = getConfirmationForIconDrop(viewId);
     91             mDelegate.handleAccessibleDrop(mView, getItemBounds(viewId), confirmation);
     92             return true;
     93         }
     94         return false;
     95     }
     96 
     97     @Override
     98     public void onClick(View v) {
     99         onPerformActionForVirtualView(getFocusedVirtualView(),
    100                 AccessibilityNodeInfoCompat.ACTION_CLICK, null);
    101     }
    102 
    103     @Override
    104     protected void onPopulateEventForVirtualView(int id, AccessibilityEvent event) {
    105         if (id == INVALID_ID) {
    106             throw new IllegalArgumentException("Invalid virtual view id");
    107         }
    108         event.setContentDescription(mContext.getString(R.string.action_move_here));
    109     }
    110 
    111     @Override
    112     protected void onPopulateNodeForVirtualView(int id, AccessibilityNodeInfoCompat node) {
    113         if (id == INVALID_ID) {
    114             throw new IllegalArgumentException("Invalid virtual view id");
    115         }
    116 
    117         node.setContentDescription(getLocationDescriptionForIconDrop(id));
    118         node.setBoundsInParent(getItemBounds(id));
    119 
    120         node.addAction(AccessibilityNodeInfoCompat.ACTION_CLICK);
    121         node.setClickable(true);
    122         node.setFocusable(true);
    123     }
    124 
    125     protected abstract String getLocationDescriptionForIconDrop(int id);
    126 
    127     protected abstract String getConfirmationForIconDrop(int id);
    128 
    129     private Rect getItemBounds(int id) {
    130         int cellX = id % mView.getCountX();
    131         int cellY = id / mView.getCountX();
    132         LauncherAccessibilityDelegate.DragInfo dragInfo = mDelegate.getDragInfo();
    133         mView.cellToRect(cellX, cellY, dragInfo.info.spanX, dragInfo.info.spanY, mTempRect);
    134         return mTempRect;
    135     }
    136 }