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