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 import android.view.accessibility.AccessibilityNodeInfo; 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 min..max where min 50 * and max were set by {@link ProgressBar#setMin(int)} and 51 * {@link ProgressBar#setMax(int)}, respectively. (The default values for 52 * min is 0 and max is 100.) 53 * @param fromUser True if the progress change was initiated by the user. 54 */ onProgressChanged(SeekBar seekBar, int progress, boolean fromUser)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 */ onStartTrackingTouch(SeekBar seekBar)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 */ onStopTrackingTouch(SeekBar seekBar)69 void onStopTrackingTouch(SeekBar seekBar); 70 } 71 72 private OnSeekBarChangeListener mOnSeekBarChangeListener; 73 SeekBar(Context context)74 public SeekBar(Context context) { 75 this(context, null); 76 } 77 SeekBar(Context context, AttributeSet attrs)78 public SeekBar(Context context, AttributeSet attrs) { 79 this(context, attrs, com.android.internal.R.attr.seekBarStyle); 80 } 81 SeekBar(Context context, AttributeSet attrs, int defStyleAttr)82 public SeekBar(Context context, AttributeSet attrs, int defStyleAttr) { 83 this(context, attrs, defStyleAttr, 0); 84 } 85 SeekBar(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes)86 public SeekBar(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { 87 super(context, attrs, defStyleAttr, defStyleRes); 88 } 89 90 @Override onProgressRefresh(float scale, boolean fromUser, int progress)91 void onProgressRefresh(float scale, boolean fromUser, int progress) { 92 super.onProgressRefresh(scale, fromUser, progress); 93 94 if (mOnSeekBarChangeListener != null) { 95 mOnSeekBarChangeListener.onProgressChanged(this, progress, fromUser); 96 } 97 } 98 99 /** 100 * Sets a listener to receive notifications of changes to the SeekBar's progress level. Also 101 * provides notifications of when the user starts and stops a touch gesture within the SeekBar. 102 * 103 * @param l The seek bar notification listener 104 * 105 * @see SeekBar.OnSeekBarChangeListener 106 */ setOnSeekBarChangeListener(OnSeekBarChangeListener l)107 public void setOnSeekBarChangeListener(OnSeekBarChangeListener l) { 108 mOnSeekBarChangeListener = l; 109 } 110 111 @Override onStartTrackingTouch()112 void onStartTrackingTouch() { 113 super.onStartTrackingTouch(); 114 if (mOnSeekBarChangeListener != null) { 115 mOnSeekBarChangeListener.onStartTrackingTouch(this); 116 } 117 } 118 119 @Override onStopTrackingTouch()120 void onStopTrackingTouch() { 121 super.onStopTrackingTouch(); 122 if (mOnSeekBarChangeListener != null) { 123 mOnSeekBarChangeListener.onStopTrackingTouch(this); 124 } 125 } 126 127 @Override getAccessibilityClassName()128 public CharSequence getAccessibilityClassName() { 129 return SeekBar.class.getName(); 130 } 131 132 /** @hide */ 133 @Override onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info)134 public void onInitializeAccessibilityNodeInfoInternal(AccessibilityNodeInfo info) { 135 super.onInitializeAccessibilityNodeInfoInternal(info); 136 137 if (canUserSetProgress()) { 138 info.addAction(AccessibilityNodeInfo.AccessibilityAction.ACTION_SET_PROGRESS); 139 } 140 } 141 } 142