1/*
2 * Copyright (C) 2006 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 android.widget;
18
19import android.content.Context;
20import android.util.AttributeSet;
21import android.view.accessibility.AccessibilityEvent;
22import android.view.accessibility.AccessibilityNodeInfo;
23
24
25
26/**
27 * A SeekBar is an extension of ProgressBar that adds a draggable thumb. The user can touch
28 * the thumb and drag left or right to set the current progress level or use the arrow keys.
29 * Placing focusable widgets to the left or right of a SeekBar is discouraged.
30 * <p>
31 * Clients of the SeekBar can attach a {@link SeekBar.OnSeekBarChangeListener} to
32 * be notified of the user's actions.
33 *
34 * @attr ref android.R.styleable#SeekBar_thumb
35 */
36public class SeekBar extends AbsSeekBar {
37
38    /**
39     * A callback that notifies clients when the progress level has been
40     * changed. This includes changes that were initiated by the user through a
41     * touch gesture or arrow key/trackball as well as changes that were initiated
42     * programmatically.
43     */
44    public interface OnSeekBarChangeListener {
45
46        /**
47         * Notification that the progress level has changed. Clients can use the fromUser parameter
48         * to distinguish user-initiated changes from those that occurred programmatically.
49         *
50         * @param seekBar The SeekBar whose progress has changed
51         * @param progress The current progress level. This will be in the range 0..max where max
52         *        was set by {@link ProgressBar#setMax(int)}. (The default value for max is 100.)
53         * @param fromUser True if the progress change was initiated by the user.
54         */
55        void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser);
56
57        /**
58         * Notification that the user has started a touch gesture. Clients may want to use this
59         * to disable advancing the seekbar.
60         * @param seekBar The SeekBar in which the touch gesture began
61         */
62        void onStartTrackingTouch(SeekBar seekBar);
63
64        /**
65         * Notification that the user has finished a touch gesture. Clients may want to use this
66         * to re-enable advancing the seekbar.
67         * @param seekBar The SeekBar in which the touch gesture began
68         */
69        void onStopTrackingTouch(SeekBar seekBar);
70    }
71
72    private OnSeekBarChangeListener mOnSeekBarChangeListener;
73
74    public SeekBar(Context context) {
75        this(context, null);
76    }
77
78    public SeekBar(Context context, AttributeSet attrs) {
79        this(context, attrs, com.android.internal.R.attr.seekBarStyle);
80    }
81
82    public SeekBar(Context context, AttributeSet attrs, int defStyle) {
83        super(context, attrs, defStyle);
84    }
85
86    @Override
87    void onProgressRefresh(float scale, boolean fromUser) {
88        super.onProgressRefresh(scale, fromUser);
89
90        if (mOnSeekBarChangeListener != null) {
91            mOnSeekBarChangeListener.onProgressChanged(this, getProgress(), fromUser);
92        }
93    }
94
95    /**
96     * Sets a listener to receive notifications of changes to the SeekBar's progress level. Also
97     * provides notifications of when the user starts and stops a touch gesture within the SeekBar.
98     *
99     * @param l The seek bar notification listener
100     *
101     * @see SeekBar.OnSeekBarChangeListener
102     */
103    public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
104        mOnSeekBarChangeListener = l;
105    }
106
107    @Override
108    void onStartTrackingTouch() {
109        super.onStartTrackingTouch();
110        if (mOnSeekBarChangeListener != null) {
111            mOnSeekBarChangeListener.onStartTrackingTouch(this);
112        }
113    }
114
115    @Override
116    void onStopTrackingTouch() {
117        super.onStopTrackingTouch();
118        if (mOnSeekBarChangeListener != null) {
119            mOnSeekBarChangeListener.onStopTrackingTouch(this);
120        }
121    }
122
123    @Override
124    public void onInitializeAccessibilityEvent(AccessibilityEvent event) {
125        super.onInitializeAccessibilityEvent(event);
126        event.setClassName(SeekBar.class.getName());
127    }
128
129    @Override
130    public void onInitializeAccessibilityNodeInfo(AccessibilityNodeInfo info) {
131        super.onInitializeAccessibilityNodeInfo(info);
132        info.setClassName(SeekBar.class.getName());
133    }
134}
135