/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.policy;
import android.content.Context;
import android.util.Slog;
import android.view.MotionEvent;
import android.view.WindowManagerPolicy.PointerEventListener;
/*
* Listens for system-wide input gestures, firing callbacks when detected.
* @hide
*/
public class SystemGesturesPointerEventListener implements PointerEventListener {
private static final String TAG = "SystemGestures";
private static final boolean DEBUG = false;
private static final long SWIPE_TIMEOUT_MS = 500;
private static final int MAX_TRACKED_POINTERS = 32; // max per input system
private static final int UNTRACKED_POINTER = -1;
private static final int SWIPE_NONE = 0;
private static final int SWIPE_FROM_TOP = 1;
private static final int SWIPE_FROM_BOTTOM = 2;
private static final int SWIPE_FROM_RIGHT = 3;
private final int mSwipeStartThreshold;
private final int mSwipeDistanceThreshold;
private final Callbacks mCallbacks;
private final int[] mDownPointerId = new int[MAX_TRACKED_POINTERS];
private final float[] mDownX = new float[MAX_TRACKED_POINTERS];
private final float[] mDownY = new float[MAX_TRACKED_POINTERS];
private final long[] mDownTime = new long[MAX_TRACKED_POINTERS];
int screenHeight;
int screenWidth;
private int mDownPointers;
private boolean mSwipeFireable;
private boolean mDebugFireable;
public SystemGesturesPointerEventListener(Context context, Callbacks callbacks) {
mCallbacks = checkNull("callbacks", callbacks);
mSwipeStartThreshold = checkNull("context", context).getResources()
.getDimensionPixelSize(com.android.internal.R.dimen.status_bar_height);
mSwipeDistanceThreshold = mSwipeStartThreshold;
if (DEBUG) Slog.d(TAG, "mSwipeStartThreshold=" + mSwipeStartThreshold
+ " mSwipeDistanceThreshold=" + mSwipeDistanceThreshold);
}
private static <T> T checkNull(String name, T arg) {
if (arg == null) {
throw new IllegalArgumentException(name + " must not be null");
}
return arg;
}
@Override
public void onPointerEvent(MotionEvent event) {
switch (event.getActionMasked()) {
case MotionEvent.ACTION_DOWN:
mSwipeFireable = true;
mDebugFireable = true;
mDownPointers = 0;
captureDown(event, 0);
mCallbacks.onDown();
break;
case MotionEvent.ACTION_POINTER_DOWN:
captureDown(event, event.getActionIndex());
if (mDebugFireable) {
mDebugFireable = event.getPointerCount() < 5;
if (!mDebugFireable) {
if (DEBUG) Slog.d(TAG, "Firing debug");
mCallbacks.onDebug();
}
}
break;
case MotionEvent.ACTION_MOVE:
if (mSwipeFireable) {
final int swipe = detectSwipe(event);
mSwipeFireable = swipe == SWIPE_NONE;
if (swipe == SWIPE_FROM_TOP) {
if (DEBUG) Slog.d(TAG, "Firing onSwipeFromTop");
mCallbacks.onSwipeFromTop();
} else if (swipe == SWIPE_FROM_BOTTOM) {
if (DEBUG) Slog.d(TAG, "Firing onSwipeFromBottom");
mCallbacks.onSwipeFromBottom();
} else if (swipe == SWIPE_FROM_RIGHT) {
if (DEBUG) Slog.d(TAG, "Firing onSwipeFromRight");
mCallbacks.onSwipeFromRight();
}
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
mSwipeFireable = false;
mDebugFireable = false;
mCallbacks.onUpOrCancel();
break;
default:
if (DEBUG) Slog.d(TAG, "Ignoring " + event);
}
}
private void captureDown(MotionEvent event, int pointerIndex) {
final int pointerId = event.getPointerId(pointerIndex);
final int i = findIndex(pointerId);
if (DEBUG) Slog.d(TAG, "pointer " + pointerId +
" down pointerIndex=" + pointerIndex + " trackingIndex=" + i);
if (i != UNTRACKED_POINTER) {
mDownX[i] = event.getX(pointerIndex);
mDownY[i] = event.getY(pointerIndex);
mDownTime[i] = event.getEventTime();
if (DEBUG) Slog.d(TAG, "pointer " + pointerId +
" down x=" + mDownX[i] + " y=" + mDownY[i]);
}
}
private int findIndex(int pointerId) {
for (int i = 0; i < mDownPointers; i++) {
if (mDownPointerId[i] == pointerId) {
return i;
}
}
if (mDownPointers == MAX_TRACKED_POINTERS || pointerId == MotionEvent.INVALID_POINTER_ID) {
return UNTRACKED_POINTER;
}
mDownPointerId[mDownPointers++] = pointerId;
return mDownPointers - 1;
}
private int detectSwipe(MotionEvent move) {
final int historySize = move.getHistorySize();
final int pointerCount = move.getPointerCount();
for (int p = 0; p < pointerCount; p++) {
final int pointerId = move.getPointerId(p);
final int i = findIndex(pointerId);
if (i != UNTRACKED_POINTER) {
for (int h = 0; h < historySize; h++) {
final long time = move.getHistoricalEventTime(h);
final float x = move.getHistoricalX(p, h);
final float y = move.getHistoricalY(p, h);
final int swipe = detectSwipe(i, time, x, y);
if (swipe != SWIPE_NONE) {
return swipe;
}
}
final int swipe = detectSwipe(i, move.getEventTime(), move.getX(p), move.getY(p));
if (swipe != SWIPE_NONE) {
return swipe;
}
}
}
return SWIPE_NONE;
}
private int detectSwipe(int i, long time, float x, float y) {
final float fromX = mDownX[i];
final float fromY = mDownY[i];
final long elapsed = time - mDownTime[i];
if (DEBUG) Slog.d(TAG, "pointer " + mDownPointerId[i]
+ " moved (" + fromX + "->" + x + "," + fromY + "->" + y + ") in " + elapsed);
if (fromY <= mSwipeStartThreshold
&& y > fromY + mSwipeDistanceThreshold
&& elapsed < SWIPE_TIMEOUT_MS) {
return SWIPE_FROM_TOP;
}
if (fromY >= screenHeight - mSwipeStartThreshold
&& y < fromY - mSwipeDistanceThreshold
&& elapsed < SWIPE_TIMEOUT_MS) {
return SWIPE_FROM_BOTTOM;
}
if (fromX >= screenWidth - mSwipeStartThreshold
&& x < fromX - mSwipeDistanceThreshold
&& elapsed < SWIPE_TIMEOUT_MS) {
return SWIPE_FROM_RIGHT;
}
return SWIPE_NONE;
}
interface Callbacks {
void onSwipeFromTop();
void onSwipeFromBottom();
void onSwipeFromRight();
void onDown();
void onUpOrCancel();
void onDebug();
}
}