1 /*
2  * Copyright (C) 2015 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 package com.android.messaging.ui.mediapicker;
17 
18 import android.content.Context;
19 import android.os.SystemClock;
20 import android.util.AttributeSet;
21 import android.widget.Chronometer;
22 
23 import com.android.messaging.ui.PlaybackStateView;
24 
25 /**
26  * A pausable Chronometer implementation. The default Chronometer in Android only stops the UI
27  * from updating when you call stop(), but doesn't actually pause it. This implementation adds an
28  * additional timestamp that tracks the timespan for the pause and compensate for that.
29  */
30 public class PausableChronometer extends Chronometer implements PlaybackStateView {
31     // Keeps track of how far long the Chronometer has been tracking when it's paused. We'd like
32     // to start from this time the next time it's resumed.
33     private long mTimeWhenPaused = 0;
34 
PausableChronometer(final Context context, final AttributeSet attrs)35     public PausableChronometer(final Context context, final AttributeSet attrs) {
36         super(context, attrs);
37     }
38 
39     /**
40      * Reset the timer and start counting from zero.
41      */
42     @Override
restart()43     public void restart() {
44         reset();
45         start();
46     }
47 
48     /**
49      * Reset the timer to zero, but don't start it.
50      */
51     @Override
reset()52     public void reset() {
53         stop();
54         setBase(SystemClock.elapsedRealtime());
55         mTimeWhenPaused = 0;
56     }
57 
58     /**
59      * Resume the timer after a previous pause.
60      */
61     @Override
resume()62     public void resume() {
63         setBase(SystemClock.elapsedRealtime() - mTimeWhenPaused);
64         start();
65     }
66 
67     /**
68      * Pause the timer.
69      */
70     @Override
pause()71     public void pause() {
72         stop();
73         mTimeWhenPaused = SystemClock.elapsedRealtime() - getBase();
74     }
75 }
76