RecentsViewTouchHandler.java revision c0d7058b14c24cd07912f5629c26b39b7b4673d5 
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;
23
24import com.android.systemui.recents.Recents;
25import com.android.systemui.recents.RecentsConfiguration;
26import com.android.systemui.recents.events.EventBus;
27import com.android.systemui.recents.events.ui.dragndrop.DragDropTargetChangedEvent;
28import com.android.systemui.recents.events.ui.dragndrop.DragEndEvent;
29import com.android.systemui.recents.events.ui.dragndrop.DragStartEvent;
30import com.android.systemui.recents.events.ui.dragndrop.DragStartInitializeDropTargetsEvent;
31import com.android.systemui.recents.misc.SystemServicesProxy;
32import com.android.systemui.recents.model.Task;
33import com.android.systemui.recents.model.TaskStack;
34
35import java.util.ArrayList;
36
37
38/**
39 * Represents the dock regions for each orientation.
40 */
41class DockRegion {
42    public static TaskStack.DockState[] PHONE_LANDSCAPE = {
43            // We only allow docking to the left for now on small devices
44            TaskStack.DockState.LEFT
45    };
46    public static TaskStack.DockState[] PHONE_PORTRAIT = {
47            // We only allow docking to the top for now on small devices
48            TaskStack.DockState.TOP
49    };
50    public static TaskStack.DockState[] TABLET_LANDSCAPE = {
51            TaskStack.DockState.LEFT,
52            TaskStack.DockState.RIGHT
53    };
54    public static TaskStack.DockState[] TABLET_PORTRAIT = PHONE_PORTRAIT;
55}
56
57/**
58 * Handles touch events for a RecentsView.
59 */
60public class RecentsViewTouchHandler {
61
62    private RecentsView mRv;
63
64    private Task mDragTask;
65    private TaskView mTaskView;
66
67    private Point mTaskViewOffset = new Point();
68    private Point mDownPos = new Point();
69    private boolean mDragRequested;
70    private boolean mIsDragging;
71    private float mDragSlop;
72
73    private DropTarget mLastDropTarget;
74    private ArrayList<DropTarget> mDropTargets = new ArrayList<>();
75    private ArrayList<TaskStack.DockState> mVisibleDockStates = new ArrayList<>();
76
77    public RecentsViewTouchHandler(RecentsView rv) {
78        mRv = rv;
79        mDragSlop = ViewConfiguration.get(rv.getContext()).getScaledTouchSlop();
80    }
81
82    /**
83     * Registers a new drop target for the current drag only.
84     */
85    public void registerDropTargetForCurrentDrag(DropTarget target) {
86        mDropTargets.add(target);
87    }
88
89    /**
90     * Returns the preferred dock states for the current orientation.
91     */
92    public TaskStack.DockState[] getDockStatesForCurrentOrientation() {
93        boolean isLandscape = mRv.getResources().getConfiguration().orientation ==
94                Configuration.ORIENTATION_LANDSCAPE;
95        RecentsConfiguration config = Recents.getConfiguration();
96        TaskStack.DockState[] dockStates = isLandscape ?
97                (config.isLargeScreen ? DockRegion.TABLET_LANDSCAPE : DockRegion.PHONE_LANDSCAPE) :
98                (config.isLargeScreen ? DockRegion.TABLET_PORTRAIT : DockRegion.PHONE_PORTRAIT);
99        return dockStates;
100    }
101
102    /**
103     * Returns the set of visible dock states for this current drag.
104     */
105    public ArrayList<TaskStack.DockState> getVisibleDockStates() {
106        return mVisibleDockStates;
107    }
108
109    /** Touch preprocessing for handling below */
110    public boolean onInterceptTouchEvent(MotionEvent ev) {
111        handleTouchEvent(ev);
112        return mDragRequested;
113    }
114
115    /** Handles touch events once we have intercepted them */
116    public boolean onTouchEvent(MotionEvent ev) {
117        handleTouchEvent(ev);
118        return mDragRequested;
119    }
120
121    /**** Events ****/
122
123    public final void onBusEvent(DragStartEvent event) {
124        SystemServicesProxy ssp = Recents.getSystemServices();
125        mRv.getParent().requestDisallowInterceptTouchEvent(true);
126        mDragRequested = true;
127        // We defer starting the actual drag handling until the user moves past the drag slop
128        mIsDragging = false;
129        mDragTask = event.task;
130        mTaskView = event.taskView;
131        mDropTargets.clear();
132
133        int[] recentsViewLocation = new int[2];
134        mRv.getLocationInWindow(recentsViewLocation);
135        mTaskViewOffset.set(mTaskView.getLeft() - recentsViewLocation[0] + event.tlOffset.x,
136                mTaskView.getTop() - recentsViewLocation[1] + event.tlOffset.y);
137        float x = mDownPos.x - mTaskViewOffset.x;
138        float y = mDownPos.y - mTaskViewOffset.y;
139        mTaskView.setTranslationX(x);
140        mTaskView.setTranslationY(y);
141
142        mVisibleDockStates.clear();
143        if (!ssp.hasDockedTask() && mRv.getTaskStack().getTaskCount() > 1) {
144            // Add the dock state drop targets (these take priority)
145            TaskStack.DockState[] dockStates = getDockStatesForCurrentOrientation();
146            for (TaskStack.DockState dockState : dockStates) {
147                registerDropTargetForCurrentDrag(dockState);
148                mVisibleDockStates.add(dockState);
149            }
150        }
151
152        // Request other drop targets to register themselves
153        EventBus.getDefault().send(new DragStartInitializeDropTargetsEvent(event.task, this));
154    }
155
156    public final void onBusEvent(DragEndEvent event) {
157        mDragRequested = false;
158        mDragTask = null;
159        mTaskView = null;
160        mLastDropTarget = null;
161    }
162
163    /**
164     * Handles dragging touch events
165     */
166    private void handleTouchEvent(MotionEvent ev) {
167        int action = ev.getAction();
168        switch (action & MotionEvent.ACTION_MASK) {
169            case MotionEvent.ACTION_DOWN:
170                mDownPos.set((int) ev.getX(), (int) ev.getY());
171                break;
172            case MotionEvent.ACTION_MOVE: {
173                float evX = ev.getX();
174                float evY = ev.getY();
175                float x = evX - mTaskViewOffset.x;
176                float y = evY - mTaskViewOffset.y;
177
178                if (mDragRequested) {
179                    if (!mIsDragging) {
180                        mIsDragging = Math.hypot(evX - mDownPos.x, evY - mDownPos.y) > mDragSlop;
181                    }
182                    if (mIsDragging) {
183                        int width = mRv.getMeasuredWidth();
184                        int height = mRv.getMeasuredHeight();
185
186                        DropTarget currentDropTarget = null;
187
188                        // Give priority to the current drop target to retain the touch handling
189                        if (mLastDropTarget != null) {
190                            if (mLastDropTarget.acceptsDrop((int) evX, (int) evY, width, height,
191                                    true /* isCurrentTarget */)) {
192                                currentDropTarget = mLastDropTarget;
193                            }
194                        }
195
196                        // Otherwise, find the next target to handle this event
197                        if (currentDropTarget == null) {
198                            for (DropTarget target : mDropTargets) {
199                                if (target.acceptsDrop((int) evX, (int) evY, width, height,
200                                        false /* isCurrentTarget */)) {
201                                    currentDropTarget = target;
202                                    break;
203                                }
204                            }
205                        }
206                        if (mLastDropTarget != currentDropTarget) {
207                            mLastDropTarget = currentDropTarget;
208                            EventBus.getDefault().send(new DragDropTargetChangedEvent(mDragTask,
209                                    currentDropTarget));
210                        }
211
212                    }
213
214                    mTaskView.setTranslationX(x);
215                    mTaskView.setTranslationY(y);
216                }
217                break;
218            }
219            case MotionEvent.ACTION_UP:
220            case MotionEvent.ACTION_CANCEL: {
221                if (mDragRequested) {
222                    EventBus.getDefault().send(new DragEndEvent(mDragTask, mTaskView,
223                            mLastDropTarget));
224                    break;
225                }
226            }
227        }
228    }
229}
230