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.compat.annotation.UnsupportedAppUsage;
20 import android.content.Context;
21 import android.util.AttributeSet;
22 import android.view.accessibility.AccessibilityNodeInfo;
23 
24 
25 /**
26  * A SeekBar is an extension of ProgressBar that adds a draggable thumb. The user can touch
27  * the thumb and drag left or right to set the current progress level or use the arrow keys.
28  * Placing focusable widgets to the left or right of a SeekBar is discouraged.
29  * <p>
30  * Clients of the SeekBar can attach a {@link SeekBar.OnSeekBarChangeListener} to
31  * be notified of the user's actions.
32  *
33  * @attr ref android.R.styleable#SeekBar_thumb
34  */
35 public class SeekBar extends AbsSeekBar {
36 
37     /**
38      * A callback that notifies clients when the progress level has been
39      * changed. This includes changes that were initiated by the user through a
40      * touch gesture or arrow key/trackball as well as changes that were initiated
41      * programmatically.
42      */
43     public interface OnSeekBarChangeListener {
44 
45         /**
46          * Notification that the progress level has changed. Clients can use the fromUser parameter
47          * to distinguish user-initiated changes from those that occurred programmatically.
48          *
49          * @param seekBar The SeekBar whose progress has changed
50          * @param progress The current progress level. This will be in the range min..max where min
51          *                 and max were set by {@link ProgressBar#setMin(int)} and
52          *                 {@link ProgressBar#setMax(int)}, respectively. (The default values for
53          *                 min is 0 and max is 100.)
54          * @param fromUser True if the progress change was initiated by the user.
55          */
onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)56         void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser);
57 
58         /**
59          * Notification that the user has started a touch gesture. Clients may want to use this
60          * to disable advancing the seekbar.
61          * @param seekBar The SeekBar in which the touch gesture began
62          */
onStartTrackingTouch(SeekBar seekBar)63         void onStartTrackingTouch(SeekBar seekBar);
64 
65         /**
66          * Notification that the user has finished a touch gesture. Clients may want to use this
67          * to re-enable advancing the seekbar.
68          * @param seekBar The SeekBar in which the touch gesture began
69          */
onStopTrackingTouch(SeekBar seekBar)70         void onStopTrackingTouch(SeekBar seekBar);
71     }
72 
73     @UnsupportedAppUsage
74     private OnSeekBarChangeListener mOnSeekBarChangeListener;
75 
SeekBar(Context context)76     public SeekBar(Context context) {
77         this(context, null);
78     }
79 
SeekBar(Context context, AttributeSet attrs)80     public SeekBar(Context context, AttributeSet attrs) {
81         this(context, attrs, com.android.internal.R.attr.seekBarStyle);
82     }
83 
SeekBar(Context context, AttributeSet attrs, int defStyleAttr)84     public SeekBar(Context context, AttributeSet attrs, int defStyleAttr) {
85         this(context, attrs, defStyleAttr, 0);
86     }
87 
SeekBar(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)88     public SeekBar(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
89         super(context, attrs, defStyleAttr, defStyleRes);
90     }
91 
92     @Override
93     @UnsupportedAppUsage
onProgressRefresh(float scale, boolean fromUser, int progress)94     void onProgressRefresh(float scale, boolean fromUser, int progress) {
95         super.onProgressRefresh(scale, fromUser, progress);
96 
97         if (mOnSeekBarChangeListener != null) {
98             mOnSeekBarChangeListener.onProgressChanged(this, progress, fromUser);
99         }
100     }
101 
102     /**
103      * Sets a listener to receive notifications of changes to the SeekBar's progress level. Also
104      * provides notifications of when the user starts and stops a touch gesture within the SeekBar.
105      *
106      * @param l The seek bar notification listener
107      *
108      * @see SeekBar.OnSeekBarChangeListener
109      */
setOnSeekBarChangeListener(OnSeekBarChangeListener l)110     public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
111         mOnSeekBarChangeListener = l;
112     }
113 
114     @Override
onStartTrackingTouch()115     void onStartTrackingTouch() {
116         super.onStartTrackingTouch();
117         if (mOnSeekBarChangeListener != null) {
118             mOnSeekBarChangeListener.onStartTrackingTouch(this);
119         }
120     }
121 
122     @Override
onStopTrackingTouch()123     void onStopTrackingTouch() {
124         super.onStopTrackingTouch();
125         if (mOnSeekBarChangeListener != null) {
126             mOnSeekBarChangeListener.onStopTrackingTouch(this);
127         }
128     }
129 
130     @Override
getAccessibilityClassName()131     public CharSequence getAccessibilityClassName() {
132         return SeekBar.class.getName();
133     }
134 
135     /** @hide */
136     @Override
onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info)137     public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) {
138         super.onInitializeAccessibilityNodeInfoInternal(info);
139 
140         if (canUserSetProgress()) {
141             info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SET_PROGRESS);
142         }
143     }
144 }
145