Android播放音乐时,在设置中调节铃声大小或者设置铃声的时候提示音与音乐一起播放
最开始遇到这个问题的思路是在选择音乐时发送一条广播给music然后让它暂停音乐
代码如下：
public class MainActivity extends AppCompatActivity {
private static boolean flagMusic;
private AudioManager audioManager = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
boolean vIsActive = audioManager.isMusicActive();
if (vIsActive) {
Toast.makeText(getApplicationContext(), "有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = true;//记录音乐播放状态 true为正在播放 ，反之
pauseMusic();//暂停音乐播放
} else {
Toast.makeText(getApplicationContext(), "没有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = false;
}
}
private void pauseMusic() {
Intent freshIntent = new Intent();
freshIntent.setAction("com.android.music.musicservicecommand.pause");
freshIntent.putExtra("command", "pause");
sendBroadcast(freshIntent);
}
private void continuMusic() {
Intent freshIntent = new Intent();
freshIntent.setAction("com.android.music.musicservicecommand.togglepause");
freshIntent.putExtra("command", "togglepause");
sendBroadcast(freshIntent);
}
@Override
protected void onStart() {
super.onStart();
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
boolean vIsActive = audioManager.isMusicActive();
if (vIsActive) {
Toast.makeText(getApplicationContext(), "有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = true;//记录音乐播放状态 true为正在播放 ，反之
pauseMusic();//暂停音乐播放
} else {
Toast.makeText(getApplicationContext(), "没有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = false;
}
}
@Override
protected void onPause() {
super.onPause();
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
boolean vIsActive = audioManager.isMusicActive();
if (!vIsActive) {
Toast.makeText(getApplicationContext(), "有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = true;//记录音乐播放状态 true为正在播放 ，反之
continuMusic();//暂停音乐播放
} else {
Toast.makeText(getApplicationContext(), "没有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = false;
}
}
@Override
protected void onDestroy() {
super.onDestroy();
audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
boolean vIsActive = audioManager.isMusicActive();
if (!vIsActive) {
Toast.makeText(getApplicationContext(), "有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = true;//记录音乐播放状态 true为正在播放 ，反之
continuMusic();//暂停音乐播放
} else {
Toast.makeText(getApplicationContext(), "没有音乐在播放", Toast.LENGTH_SHORT).show();
flagMusic = false;
}
}
}但是这个只针对自带音乐app生效 所以换了个思路
在设置调节音量的时候获取音频焦点 调节结束的时候松开之后释放音频焦点
这样在调节的时候就可以暂停音乐 松开之后音乐自动就开始播放了
首先在源码中找到对应的类：
/frameworks/base/core/java/android/preference/SeekBarVolumizer.java
类应是调节音量的SeekBar
首先来看Seekar的三个回调函数：
@Override
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
mHandler.sendEmptyMessageDelayed(1,500);
//开始调节SeekBar的时候会调用这里
}
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
//调节SeekBar结束的时候会调用这里
}我们来看一下AOSP中的源码：
public void onProgressChanged(SeekBar seekBar, int progress, boolean fromTouch) {
if (fromTouch) {
postSetVolume(progress);
}
if (mCallback != null) {
mCallback.onProgressChanged(seekBar, progress, fromTouch);
}
}
private void postSetVolume(int progress) {
if (mHandler == null) return;
// Do the volume changing separately to give responsive UI
mLastProgress = progress;
mHandler.removeMessages(MSG_SET_STREAM_VOLUME);
mHandler.sendMessage(mHandler.obtainMessage(MSG_SET_STREAM_VOLUME));
}
public void onStartTrackingTouch(SeekBar seekBar) {
}
public void onStopTrackingTouch(SeekBar seekBar) {
postStartSample();//松开SeekBar的时候播放提示音
}方法其实很简单:
在onStartTrackingTouch()的时候获取到音频焦点
在onStopTrackingTouch()时释放焦点
这样在滑动SeekBar的时候后台的音乐会暂停
松开SeekBar的时候音乐就继续播放了，代码如下：
public void onStartTrackingTouch(SeekBar seekBar) {
mAudioManager.requestAudioFocus(mAudioFocusListener, AudioManager.STREAM_RING, AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
}
public void onStopTrackingTouch(SeekBar seekBar) {
mAudioManager.abandonAudioFocus(mAudioFocusListener);
postStartSample();
Log.e("SeekBarVolumizer","Start to play cue music");
}
private AudioManager.OnAudioFocusChangeListener mAudioFocusListener = new AudioManager.OnAudioFocusChangeListener() {
public void onAudioFocusChange(int focusChange) {
Log.d(TAG, "onAudioFocusChange:" + focusChange );
switch (focusChange) {
case AudioManager.AUDIOFOCUS_LOSS:
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
break;
}
}
};但是 当你编译好之后会发现
松开SeekBar的时候 后台的音乐会和调节音量后的提示音一起播放了
原因是因为在系统播放提示音的时候没有去requestAudioFocus()
而直接去播放了提示音
顺着postStartSample();往下找会发现：
private void postStartSample() {
if (mHandler == null) return;
mHandler.removeMessages(MSG_START_SAMPLE);
mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_START_SAMPLE),
isSamplePlaying() ? CHECK_RINGTONE_PLAYBACK_DELAY_MS : 0);
}发送了一条MSG_START_SAMPLE，最后执行的代码如下：
private void onStartSample() {
if (!isSamplePlaying()) {
if (mCallback != null) {
mCallback.onSampleStarting(this);
}
synchronized (this) {
if (mRingtone != null) {
try {
mRingtone.setAudioAttributes(new AudioAttributes.Builder(mRingtone
.getAudioAttributes())
.setFlags(AudioAttributes.FLAG_BYPASS_MUTE)
.build());
mAudioManager.requestAudioFocus(mAudioFocusListener, AudioManager.STREAM_RING, AudioManager.AUDIOFOCUS_GAIN_TRANSIENT); //获得音频焦点
mRingtone.play(); //播放提示音
mHandler.sendMessageDelayed(mHandler.obtainMessage(MSG_INIT_WAITING),1000); //延迟1秒钟之后释放焦点
} catch (Throwable e) {
Log.w(TAG, "Error playing ringtone, stream " + mStreamType, e);
}
}
}
}
}handleMessage()如下：
@Override
public boolean handleMessage(Message msg) {
switch (msg.what) {
case MSG_SET_STREAM_VOLUME:
if (mMuted && mLastProgress > 0) {
mAudioManager.adjustStreamVolume(mStreamType, AudioManager.ADJUST_UNMUTE, 0);
} else if (!mMuted && mLastProgress == 0) {
mAudioManager.adjustStreamVolume(mStreamType, AudioManager.ADJUST_MUTE, 0);
}
mAudioManager.setStreamVolume(mStreamType, mLastProgress,
AudioManager.FLAG_SHOW_UI_WARNINGS);
break;
case MSG_START_SAMPLE:
onStartSample();
break;
case MSG_STOP_SAMPLE:
onStopSample();
break;
case MSG_INIT_SAMPLE:
onInitSample();
break;
case MSG_INIT_WAITING:
mAudioManager.abandonAudioFocus(mAudioFocusListener);
break;
default:
Log.e(TAG, "invalid SeekBarVolumizer message: "+msg.what);
}
return true;
}这样滑动SeekBar的时候音乐会暂停下来 松开SeekBar之后播放提示音 一秒之后音乐就会继续播放啦
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