RecentsViewTouchHandler.java revision 3e8747414520ee348cf4b9c4a6afd9ff80b5a8f8 
1/*
2 * Copyright (C) 2014 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.systemui.recents.views;
18
19import android.content.res.Configuration;
20import android.graphics.Point;
21import android.view.MotionEvent;
22import android.view.ViewConfiguration;
23import com.android.systemui.recents.Recents;
24import com.android.systemui.recents.RecentsConfiguration;
25import com.android.systemui.recents.events.EventBus;
26import com.android.systemui.recents.events.ui.dragndrop.DragDropTargetChangedEvent;
27import com.android.systemui.recents.events.ui.dragndrop.DragEndEvent;
28import com.android.systemui.recents.events.ui.dragndrop.DragStartEvent;
29import com.android.systemui.recents.events.ui.dragndrop.DragStartInitializeDropTargetsEvent;
30import com.android.systemui.recents.misc.SystemServicesProxy;
31import com.android.systemui.recents.model.Task;
32import com.android.systemui.recents.model.TaskStack;
33
34import java.util.ArrayList;
35
36
37/**
38 * Represents the dock regions for each orientation.
39 */
40class DockRegion {
41    public static TaskStack.DockState[] PHONE_LANDSCAPE = {
42            // We only allow docking to the left for now on small devices
43            TaskStack.DockState.LEFT
44    };
45    public static TaskStack.DockState[] PHONE_PORTRAIT = {
46            // We only allow docking to the top for now on small devices
47            TaskStack.DockState.TOP
48    };
49    public static TaskStack.DockState[] TABLET_LANDSCAPE = {
50            TaskStack.DockState.LEFT,
51            TaskStack.DockState.RIGHT
52    };
53    public static TaskStack.DockState[] TABLET_PORTRAIT = PHONE_PORTRAIT;
54}
55
56/**
57 * Handles touch events for a RecentsView.
58 */
59public class RecentsViewTouchHandler {
60
61    private RecentsView mRv;
62
63    private Task mDragTask;
64    private TaskView mTaskView;
65
66    private Point mTaskViewOffset = new Point();
67    private Point mDownPos = new Point();
68    private boolean mDragRequested;
69    private boolean mIsDragging;
70    private float mDragSlop;
71
72    private DropTarget mLastDropTarget;
73    private ArrayList<DropTarget> mDropTargets = new ArrayList<>();
74
75    public RecentsViewTouchHandler(RecentsView rv) {
76        mRv = rv;
77        mDragSlop = ViewConfiguration.get(rv.getContext()).getScaledTouchSlop();
78    }
79
80    /**
81     * Registers a new drop target for the current drag only.
82     */
83    public void registerDropTargetForCurrentDrag(DropTarget target) {
84        mDropTargets.add(target);
85    }
86
87    /**
88     * Returns the preferred dock states for the current orientation.
89     */
90    public TaskStack.DockState[] getDockStatesForCurrentOrientation() {
91        boolean isLandscape = mRv.getResources().getConfiguration().orientation ==
92                Configuration.ORIENTATION_LANDSCAPE;
93        RecentsConfiguration config = Recents.getConfiguration();
94        TaskStack.DockState[] dockStates = isLandscape ?
95                (config.isLargeScreen ? DockRegion.TABLET_LANDSCAPE : DockRegion.PHONE_LANDSCAPE) :
96                (config.isLargeScreen ? DockRegion.TABLET_PORTRAIT : DockRegion.PHONE_PORTRAIT);
97        return dockStates;
98    }
99
100    /** Touch preprocessing for handling below */
101    public boolean onInterceptTouchEvent(MotionEvent ev) {
102        handleTouchEvent(ev);
103        return mDragRequested;
104    }
105
106    /** Handles touch events once we have intercepted them */
107    public boolean onTouchEvent(MotionEvent ev) {
108        handleTouchEvent(ev);
109        return mDragRequested;
110    }
111
112    /**** Events ****/
113
114    public final void onBusEvent(DragStartEvent event) {
115        SystemServicesProxy ssp = Recents.getSystemServices();
116        mRv.getParent().requestDisallowInterceptTouchEvent(true);
117        mDragRequested = true;
118        // We defer starting the actual drag handling until the user moves past the drag slop
119        mIsDragging = false;
120        mDragTask = event.task;
121        mTaskView = event.taskView;
122        mDropTargets.clear();
123
124        int[] recentsViewLocation = new int[2];
125        mRv.getLocationInWindow(recentsViewLocation);
126        mTaskViewOffset.set(mTaskView.getLeft() - recentsViewLocation[0] + event.tlOffset.x,
127                mTaskView.getTop() - recentsViewLocation[1] + event.tlOffset.y);
128        float x = mDownPos.x - mTaskViewOffset.x;
129        float y = mDownPos.y - mTaskViewOffset.y;
130        mTaskView.setTranslationX(x);
131        mTaskView.setTranslationY(y);
132
133        if (!ssp.hasDockedTask()) {
134            // Add the dock state drop targets (these take priority)
135            TaskStack.DockState[] dockStates = getDockStatesForCurrentOrientation();
136            for (TaskStack.DockState dockState : dockStates) {
137                registerDropTargetForCurrentDrag(dockState);
138            }
139        }
140
141        // Request other drop targets to register themselves
142        EventBus.getDefault().send(new DragStartInitializeDropTargetsEvent(event.task, this));
143    }
144
145    public final void onBusEvent(DragEndEvent event) {
146        mDragRequested = false;
147        mDragTask = null;
148        mTaskView = null;
149        mLastDropTarget = null;
150    }
151
152    /**
153     * Handles dragging touch events
154     */
155    private void handleTouchEvent(MotionEvent ev) {
156        int action = ev.getAction();
157        switch (action & MotionEvent.ACTION_MASK) {
158            case MotionEvent.ACTION_DOWN:
159                mDownPos.set((int) ev.getX(), (int) ev.getY());
160                break;
161            case MotionEvent.ACTION_MOVE: {
162                float evX = ev.getX();
163                float evY = ev.getY();
164                float x = evX - mTaskViewOffset.x;
165                float y = evY - mTaskViewOffset.y;
166
167                if (mDragRequested) {
168                    if (!mIsDragging) {
169                        mIsDragging = Math.hypot(evX - mDownPos.x, evY - mDownPos.y) > mDragSlop;
170                    }
171                    if (mIsDragging) {
172                        int width = mRv.getMeasuredWidth();
173                        int height = mRv.getMeasuredHeight();
174
175                        DropTarget currentDropTarget = null;
176
177                        // Give priority to the current drop target to retain the touch handling
178                        if (mLastDropTarget != null) {
179                            if (mLastDropTarget.acceptsDrop((int) evX, (int) evY, width, height,
180                                    true /* isCurrentTarget */)) {
181                                currentDropTarget = mLastDropTarget;
182                            }
183                        }
184
185                        // Otherwise, find the next target to handle this event
186                        if (currentDropTarget == null) {
187                            for (DropTarget target : mDropTargets) {
188                                if (target.acceptsDrop((int) evX, (int) evY, width, height,
189                                        false /* isCurrentTarget */)) {
190                                    currentDropTarget = target;
191                                    break;
192                                }
193                            }
194                        }
195                        if (mLastDropTarget != currentDropTarget) {
196                            mLastDropTarget = currentDropTarget;
197                            EventBus.getDefault().send(new DragDropTargetChangedEvent(mDragTask,
198                                    currentDropTarget));
199                        }
200
201                    }
202
203                    mTaskView.setTranslationX(x);
204                    mTaskView.setTranslationY(y);
205                }
206                break;
207            }
208            case MotionEvent.ACTION_UP:
209            case MotionEvent.ACTION_CANCEL: {
210                if (mDragRequested) {
211                    EventBus.getDefault().send(new DragEndEvent(mDragTask, mTaskView,
212                            mLastDropTarget));
213                    break;
214                }
215            }
216        }
217    }
218}
219