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      1 /*
      2  * Copyright 2017 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 com.example.android.mediasession.ui;
     18 
     19 import android.animation.ValueAnimator;
     20 import android.content.Context;
     21 import android.support.v4.media.MediaMetadataCompat;
     22 import android.support.v4.media.session.MediaControllerCompat;
     23 import android.support.v4.media.session.MediaSessionCompat;
     24 import android.support.v4.media.session.PlaybackStateCompat;
     25 import android.support.v7.widget.AppCompatSeekBar;
     26 import android.util.AttributeSet;
     27 import android.view.animation.LinearInterpolator;
     28 import android.widget.SeekBar;
     29 
     30 /**
     31  * SeekBar that can be used with a {@link MediaSessionCompat} to track and seek in playing
     32  * media.
     33  */
     34 
     35 public class MediaSeekBar extends AppCompatSeekBar {
     36     private MediaControllerCompat mMediaController;
     37     private ControllerCallback mControllerCallback;
     38 
     39     private boolean mIsTracking = false;
     40     private OnSeekBarChangeListener mOnSeekBarChangeListener = new OnSeekBarChangeListener() {
     41         @Override
     42         public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
     43         }
     44 
     45         @Override
     46         public void onStartTrackingTouch(SeekBar seekBar) {
     47             mIsTracking = true;
     48         }
     49 
     50         @Override
     51         public void onStopTrackingTouch(SeekBar seekBar) {
     52             mMediaController.getTransportControls().seekTo(getProgress());
     53             mIsTracking = false;
     54         }
     55     };
     56     private ValueAnimator mProgressAnimator;
     57 
     58     public MediaSeekBar(Context context) {
     59         super(context);
     60         super.setOnSeekBarChangeListener(mOnSeekBarChangeListener);
     61     }
     62 
     63     public MediaSeekBar(Context context, AttributeSet attrs) {
     64         super(context, attrs);
     65         super.setOnSeekBarChangeListener(mOnSeekBarChangeListener);
     66     }
     67 
     68     public MediaSeekBar(Context context, AttributeSet attrs, int defStyleAttr) {
     69         super(context, attrs, defStyleAttr);
     70         super.setOnSeekBarChangeListener(mOnSeekBarChangeListener);
     71     }
     72 
     73     @Override
     74     public final void setOnSeekBarChangeListener(OnSeekBarChangeListener l) {
     75         // Prohibit adding seek listeners to this subclass.
     76         throw new UnsupportedOperationException("Cannot add listeners to a MediaSeekBar");
     77     }
     78 
     79     public void setMediaController(final MediaControllerCompat mediaController) {
     80         if (mediaController != null) {
     81             mControllerCallback = new ControllerCallback();
     82             mediaController.registerCallback(mControllerCallback);
     83         } else if (mMediaController != null) {
     84             mMediaController.unregisterCallback(mControllerCallback);
     85             mControllerCallback = null;
     86         }
     87         mMediaController = mediaController;
     88     }
     89 
     90     public void disconnectController() {
     91         if (mMediaController != null) {
     92             mMediaController.unregisterCallback(mControllerCallback);
     93             mControllerCallback = null;
     94             mMediaController = null;
     95         }
     96     }
     97 
     98     private class ControllerCallback
     99             extends MediaControllerCompat.Callback
    100             implements ValueAnimator.AnimatorUpdateListener {
    101 
    102         @Override
    103         public void onSessionDestroyed() {
    104             super.onSessionDestroyed();
    105         }
    106 
    107         @Override
    108         public void onPlaybackStateChanged(PlaybackStateCompat state) {
    109             super.onPlaybackStateChanged(state);
    110 
    111             // If there's an ongoing animation, stop it now.
    112             if (mProgressAnimator != null) {
    113                 mProgressAnimator.cancel();
    114                 mProgressAnimator = null;
    115             }
    116 
    117             final int progress = state != null
    118                     ? (int) state.getPosition()
    119                     : 0;
    120             setProgress(progress);
    121 
    122             // If the media is playing then the seekbar should follow it, and the easiest
    123             // way to do that is to create a ValueAnimator to update it so the bar reaches
    124             // the end of the media the same time as playback gets there (or close enough).
    125             if (state != null && state.getState() == PlaybackStateCompat.STATE_PLAYING) {
    126                 final int timeToEnd = (int) ((getMax() - progress) / state.getPlaybackSpeed());
    127 
    128                 mProgressAnimator = ValueAnimator.ofInt(progress, getMax())
    129                         .setDuration(timeToEnd);
    130                 mProgressAnimator.setInterpolator(new LinearInterpolator());
    131                 mProgressAnimator.addUpdateListener(this);
    132                 mProgressAnimator.start();
    133             }
    134         }
    135 
    136         @Override
    137         public void onMetadataChanged(MediaMetadataCompat metadata) {
    138             super.onMetadataChanged(metadata);
    139 
    140             final int max = metadata != null
    141                     ? (int) metadata.getLong(MediaMetadataCompat.METADATA_KEY_DURATION)
    142                     : 0;
    143             setProgress(0);
    144             setMax(max);
    145         }
    146 
    147         @Override
    148         public void onAnimationUpdate(final ValueAnimator valueAnimator) {
    149             // If the user is changing the slider, cancel the animation.
    150             if (mIsTracking) {
    151                 valueAnimator.cancel();
    152                 return;
    153             }
    154 
    155             final int animatedIntValue = (int) valueAnimator.getAnimatedValue();
    156             setProgress(animatedIntValue);
    157         }
    158     }
    159 }
    160