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
17package com.android.launcher3.accessibility;
18
19import android.content.Context;
20import android.graphics.Rect;
21import android.os.Bundle;
22import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;
23import android.support.v4.widget.ExploreByTouchHelper;
24import android.view.View;
25import android.view.View.OnClickListener;
26import android.view.accessibility.AccessibilityEvent;
27
28import com.android.launcher3.CellLayout;
29import com.android.launcher3.LauncherAppState;
30import com.android.launcher3.R;
31
32import java.util.List;
33
34/**
35 * Helper class to make drag-and-drop in a {@link CellLayout} accessible.
36 */
37public 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 = LauncherAppState.getInstance().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}