SystemGesturesPointerEventListener.java revision d2e7e355d836f18adcdb44db9c1931d1c3663ef1 
1/*
2 * Copyright (C) 2013 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.server.policy;
18
19import android.content.Context;
20import android.util.Slog;
21import android.view.MotionEvent;
22import android.view.WindowManagerPolicy.PointerEventListener;
23
24/*
25 * Listens for system-wide input gestures, firing callbacks when detected.
26 * @hide
27 */
28public class SystemGesturesPointerEventListener implements PointerEventListener {
29    private static final String TAG = "SystemGestures";
30    private static final boolean DEBUG = false;
31    private static final long SWIPE_TIMEOUT_MS = 500;
32    private static final int MAX_TRACKED_POINTERS = 32;  // max per input system
33    private static final int UNTRACKED_POINTER = -1;
34
35    private static final int SWIPE_NONE = 0;
36    private static final int SWIPE_FROM_TOP = 1;
37    private static final int SWIPE_FROM_BOTTOM = 2;
38    private static final int SWIPE_FROM_RIGHT = 3;
39
40    private final int mSwipeStartThreshold;
41    private final int mSwipeDistanceThreshold;
42    private final Callbacks mCallbacks;
43    private final int[] mDownPointerId = new int[MAX_TRACKED_POINTERS];
44    private final float[] mDownX = new float[MAX_TRACKED_POINTERS];
45    private final float[] mDownY = new float[MAX_TRACKED_POINTERS];
46    private final long[] mDownTime = new long[MAX_TRACKED_POINTERS];
47
48    int screenHeight;
49    int screenWidth;
50    private int mDownPointers;
51    private boolean mSwipeFireable;
52    private boolean mDebugFireable;
53    private boolean mMouseHoveringAtEdge;
54
55    public SystemGesturesPointerEventListener(Context context, Callbacks callbacks) {
56        mCallbacks = checkNull("callbacks", callbacks);
57        mSwipeStartThreshold = checkNull("context", context).getResources()
58                .getDimensionPixelSize(com.android.internal.R.dimen.status_bar_height);
59        mSwipeDistanceThreshold = mSwipeStartThreshold;
60        if (DEBUG) Slog.d(TAG,  "mSwipeStartThreshold=" + mSwipeStartThreshold
61                + " mSwipeDistanceThreshold=" + mSwipeDistanceThreshold);
62    }
63
64    private static <T> T checkNull(String name, T arg) {
65        if (arg == null) {
66            throw new IllegalArgumentException(name + " must not be null");
67        }
68        return arg;
69    }
70
71    @Override
72    public void onPointerEvent(MotionEvent event) {
73        switch (event.getActionMasked()) {
74            case MotionEvent.ACTION_DOWN:
75                mSwipeFireable = true;
76                mDebugFireable = true;
77                mDownPointers = 0;
78                captureDown(event, 0);
79                if (mMouseHoveringAtEdge) {
80                    mMouseHoveringAtEdge = false;
81                    mCallbacks.onMouseLeaveFromEdge();
82                }
83                mCallbacks.onDown();
84                break;
85            case MotionEvent.ACTION_POINTER_DOWN:
86                captureDown(event, event.getActionIndex());
87                if (mDebugFireable) {
88                    mDebugFireable = event.getPointerCount() < 5;
89                    if (!mDebugFireable) {
90                        if (DEBUG) Slog.d(TAG, "Firing debug");
91                        mCallbacks.onDebug();
92                    }
93                }
94                break;
95            case MotionEvent.ACTION_MOVE:
96                if (mSwipeFireable) {
97                    final int swipe = detectSwipe(event);
98                    mSwipeFireable = swipe == SWIPE_NONE;
99                    if (swipe == SWIPE_FROM_TOP) {
100                        if (DEBUG) Slog.d(TAG, "Firing onSwipeFromTop");
101                        mCallbacks.onSwipeFromTop();
102                    } else if (swipe == SWIPE_FROM_BOTTOM) {
103                        if (DEBUG) Slog.d(TAG, "Firing onSwipeFromBottom");
104                        mCallbacks.onSwipeFromBottom();
105                    } else if (swipe == SWIPE_FROM_RIGHT) {
106                        if (DEBUG) Slog.d(TAG, "Firing onSwipeFromRight");
107                        mCallbacks.onSwipeFromRight();
108                    }
109                }
110                break;
111            case MotionEvent.ACTION_HOVER_MOVE:
112                if (event.getPointerCount() == 1
113                        && event.getToolType(0) == MotionEvent.TOOL_TYPE_MOUSE) {
114                    if (!mMouseHoveringAtEdge && event.getY() == 0) {
115                        mCallbacks.onMouseHoverAtTop();
116                        mMouseHoveringAtEdge = true;
117                    } else if (!mMouseHoveringAtEdge && event.getY() >= screenHeight - 1) {
118                        mCallbacks.onMouseHoverAtBottom();
119                        mMouseHoveringAtEdge = true;
120                    } else if (mMouseHoveringAtEdge
121                            && (event.getY() > 0 && event.getY() < screenHeight - 1)) {
122                        mCallbacks.onMouseLeaveFromEdge();
123                        mMouseHoveringAtEdge = false;
124                    }
125                }
126                break;
127            case MotionEvent.ACTION_UP:
128            case MotionEvent.ACTION_CANCEL:
129                mSwipeFireable = false;
130                mDebugFireable = false;
131                mCallbacks.onUpOrCancel();
132                break;
133            default:
134                if (DEBUG) Slog.d(TAG, "Ignoring " + event);
135        }
136    }
137
138    private void captureDown(MotionEvent event, int pointerIndex) {
139        final int pointerId = event.getPointerId(pointerIndex);
140        final int i = findIndex(pointerId);
141        if (DEBUG) Slog.d(TAG, "pointer " + pointerId +
142                " down pointerIndex=" + pointerIndex + " trackingIndex=" + i);
143        if (i != UNTRACKED_POINTER) {
144            mDownX[i] = event.getX(pointerIndex);
145            mDownY[i] = event.getY(pointerIndex);
146            mDownTime[i] = event.getEventTime();
147            if (DEBUG) Slog.d(TAG, "pointer " + pointerId +
148                    " down x=" + mDownX[i] + " y=" + mDownY[i]);
149        }
150    }
151
152    private int findIndex(int pointerId) {
153        for (int i = 0; i < mDownPointers; i++) {
154            if (mDownPointerId[i] == pointerId) {
155                return i;
156            }
157        }
158        if (mDownPointers == MAX_TRACKED_POINTERS || pointerId == MotionEvent.INVALID_POINTER_ID) {
159            return UNTRACKED_POINTER;
160        }
161        mDownPointerId[mDownPointers++] = pointerId;
162        return mDownPointers - 1;
163    }
164
165    private int detectSwipe(MotionEvent move) {
166        final int historySize = move.getHistorySize();
167        final int pointerCount = move.getPointerCount();
168        for (int p = 0; p < pointerCount; p++) {
169            final int pointerId = move.getPointerId(p);
170            final int i = findIndex(pointerId);
171            if (i != UNTRACKED_POINTER) {
172                for (int h = 0; h < historySize; h++) {
173                    final long time = move.getHistoricalEventTime(h);
174                    final float x = move.getHistoricalX(p, h);
175                    final float y = move.getHistoricalY(p,  h);
176                    final int swipe = detectSwipe(i, time, x, y);
177                    if (swipe != SWIPE_NONE) {
178                        return swipe;
179                    }
180                }
181                final int swipe = detectSwipe(i, move.getEventTime(), move.getX(p), move.getY(p));
182                if (swipe != SWIPE_NONE) {
183                    return swipe;
184                }
185            }
186        }
187        return SWIPE_NONE;
188    }
189
190    private int detectSwipe(int i, long time, float x, float y) {
191        final float fromX = mDownX[i];
192        final float fromY = mDownY[i];
193        final long elapsed = time - mDownTime[i];
194        if (DEBUG) Slog.d(TAG, "pointer " + mDownPointerId[i]
195                + " moved (" + fromX + "->" + x + "," + fromY + "->" + y + ") in " + elapsed);
196        if (fromY <= mSwipeStartThreshold
197                && y > fromY + mSwipeDistanceThreshold
198                && elapsed < SWIPE_TIMEOUT_MS) {
199            return SWIPE_FROM_TOP;
200        }
201        if (fromY >= screenHeight - mSwipeStartThreshold
202                && y < fromY - mSwipeDistanceThreshold
203                && elapsed < SWIPE_TIMEOUT_MS) {
204            return SWIPE_FROM_BOTTOM;
205        }
206        if (fromX >= screenWidth - mSwipeStartThreshold
207                && x < fromX - mSwipeDistanceThreshold
208                && elapsed < SWIPE_TIMEOUT_MS) {
209            return SWIPE_FROM_RIGHT;
210        }
211        return SWIPE_NONE;
212    }
213
214    interface Callbacks {
215        void onSwipeFromTop();
216        void onSwipeFromBottom();
217        void onSwipeFromRight();
218        void onDown();
219        void onUpOrCancel();
220        void onMouseHoverAtTop();
221        void onMouseHoverAtBottom();
222        void onMouseLeaveFromEdge();
223        void onDebug();
224    }
225}
226