1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
package com.almeros.android.multitouch.gesturedetectors;
import android.content.Context;
import android.view.MotionEvent;
/**
* @author Almer Thie (code.almeros.com) Copyright (c) 2013, Almer Thie
* (code.almeros.com)
* <p>
* All rights reserved.
* <p>
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* <p>
* Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* <p>
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
public abstract class BaseGestureDetector {
protected final Context context;
protected boolean gestureInProgress;
protected MotionEvent prevEvent;
protected MotionEvent currEvent;
protected float currPressure;
protected float prevPressure;
protected long timeDelta;
/**
* This value is the threshold ratio between the previous combined pressure
* and the current combined pressure. When pressure decreases rapidly
* between events the position values can often be imprecise, as it usually
* indicates that the user is in the process of lifting a pointer off of the
* device. This value was tuned experimentally.
*/
protected static final float PRESSURE_THRESHOLD = 0.67f;
public BaseGestureDetector(Context context) {
this.context = context;
}
/**
* All gesture detectors need to be called through this method to be able to
* detect gestures. This method delegates work to handler methods
* (handleStartProgressEvent, handleInProgressEvent) implemented in
* extending classes.
*
* @param event MotionEvent
* @return {@code true} as handled
*/
public boolean onTouchEvent(MotionEvent event) {
final int actionCode = event.getAction() & MotionEvent.ACTION_MASK;
if (!gestureInProgress) {
handleStartProgressEvent(actionCode, event);
} else {
handleInProgressEvent(actionCode, event);
}
return true;
}
/**
* Called when the current event occurred when NO gesture is in progress
* yet. The handling in this implementation may set the gesture in progress
* (via gestureInProgress) or out of progress
*
* @param actionCode Action Code from MotionEvent
* @param event MotionEvent
*/
protected abstract void handleStartProgressEvent(int actionCode,
MotionEvent event);
/**
* Called when the current event occurred when a gesture IS in progress. The
* handling in this implementation may set the gesture out of progress (via
* gestureInProgress).
*
* @param actionCode Action Code from MotionEvent
* @param event MotionEvent
*/
protected abstract void handleInProgressEvent(int actionCode,
MotionEvent event);
protected void updateStateByEvent(MotionEvent curr) {
final MotionEvent prev = prevEvent;
// Reset currEvent
if (currEvent != null) {
currEvent.recycle();
currEvent = null;
}
currEvent = MotionEvent.obtain(curr);
// Delta time
timeDelta = curr.getEventTime() - prev.getEventTime();
// Pressure
currPressure = curr.getPressure(curr.getActionIndex());
prevPressure = prev.getPressure(prev.getActionIndex());
}
protected void resetState() {
if (prevEvent != null) {
prevEvent.recycle();
prevEvent = null;
}
if (currEvent != null) {
currEvent.recycle();
currEvent = null;
}
gestureInProgress = false;
}
/**
* Returns {@code true} if a gesture is currently in progress.
*
* @return {@code true} if a gesture is currently in progress, {@code false}
* otherwise.
*/
public boolean isInProgress() {
return gestureInProgress;
}
/**
* Return the time difference in milliseconds between the previous accepted
* GestureDetector event and the current GestureDetector event.
*
* @return Time difference since the last move event in milliseconds.
*/
public long getTimeDelta() {
return timeDelta;
}
/**
* Return the event time of the current GestureDetector event being
* processed.
*
* @return Current GestureDetector event time in milliseconds.
*/
public long getEventTime() {
return currEvent.getEventTime();
}
}
|
