我使用了 AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK 但 android 系统名为 AUDIOFOCUS_LOSS_TRANSIENT。
我不知道为什么系统不调用AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK。
正常操作如下
AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK 到
AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK
请给我一些建议。
谢谢。
// MainActivity.java
package com.example.af_test;
import android.app.Activity;
import android.media.AudioManager;
import android.media.AudioManager.OnAudioFocusChangeListener;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity {
private AudioManager am;
private MediaPlayer mp;
private MediaPlayer mp_alarm;
private String LOG = "Seo";
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mp = MediaPlayer.create(this, R.raw.explosion);
mp_alarm = MediaPlayer.create(this, R.raw.caution); // test
Button btn = (Button) findViewById(R.id.btn);
btn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
am = (AudioManager) getSystemService(AUDIO_SERVICE);
int requestResult = am.requestAudioFocus(
mAudioFocusListener, AudioManager.STREAM_MUSIC,
//AudioManager.AUDIOFOCUS_GAIN);
//AudioManager.AUDIOFOCUS_GAIN_TRANSIENT);
AudioManager.AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK);
if (requestResult == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
mp.start();
Log.d(LOG, "Successfull to request audioFocus listener");
}
else if(requestResult == AudioManager.AUDIOFOCUS_REQUEST_FAILED)
{
mp.stop();
//mp_alarm.stop();
}
else {
Log.d(LOG, "Failure to request focus listener");
}
//mp.start();
// am.abandonAudioFocus(mAudioFocusListener);
// Log.d(LOG, "Abandon focus");
}
});
// 동영상 재생이 완료된걸 알수있는 리스너
mp.setOnCompletionListener(new OnCompletionListener() {
// 동영상 재생이 완료된후 호출되는 메서드
public void onCompletion(MediaPlayer player) {
am.abandonAudioFocus(mAudioFocusListener);
}
});
}
@Override
// onDestroy()는 해당 Activity가 화면에서 사라진 후에 호출된다.
protected void onDestroy() {
mp.stop();
am.abandonAudioFocus(mAudioFocusListener);
Log.d(LOG, "Abandon focus");
super.onDestroy();
}
public void abandonAudioFocus() {
//Abandon audio focus
int result = am.abandonAudioFocus(mAudioFocusListener);
if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) {
Log.d(LOG, "Audio focus abandoned");
} else {
Log.e(LOG, "Audio focus failed to abandon");
}
}
public void stop() {
mp.stop();
abandonAudioFocus();
}
private OnAudioFocusChangeListener mAudioFocusListener = new OnAudioFocusChangeListener() {
public void onAudioFocusChange(int focusChange) {
// AudioFocus is a new feature: focus updates are made verbose on
// purpose
switch (focusChange) {
case AudioManager.AUDIOFOCUS_LOSS:
mp.stop();
//stop();
Log.d(LOG, "AudioFocus: received AUDIOFOCUS_LOSS");
// mp.release();
// mp = null;
break;
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT:
// if (mp.isPlaying())
mp.pause();
Log.d(LOG, "AudioFocus: received AUDIOFOCUS_LOSS_TRANSIENT");
break;
case AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK:
mp.setVolume(0.5f, 0.5f);
Log.d(LOG, "AudioFocus: received AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK");
break;
case AudioManager.AUDIOFOCUS_GAIN:
mp.start();
mp.setVolume(1.0f, 1.0f);
Log.d(LOG, "AudioFocus: received AUDIOFOCUS_GAIN");
break;
default:
Log.e(LOG, "Unknown audio focus change code");
}
}
};
}
<!-- activity_main.xml -->
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="${relativePackage}.${activityClass}" >
<Button
android:id="@+id/btn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="Audio Focus Test" />
</RelativeLayout>
Logcat 信息
08-05 16:46:00.115: I/AudioService(2429): AudioFocus requestAudioFocus() from 11622 focusChangeHint:3
08-05 16:46:00.115: V/CorePlayerService(20934): AudioFocus: received AUDIOFOCUS_LOSS_TRANSIENT
08-05 16:46:00.165: D/Seo(11622): Successfull to request audioFocus listener
08-05 16:46:03.400: I/AudioService(2429): AudioFocus abandonAudioFocus() from 11622
08-05 16:46:03.405: V/CorePlayerService(20934): AudioFocus: received AUDIOFOCUS_GAIN
08-05 16:46:03.435: I/AudioService(2429): AudioFocus requestAudioFocus() from 20934 focusChangeHint:1
最佳答案
您对音频焦点工作原理的解释似乎有点不正确。当您失去音频焦点时，您不会根据您之前请求的GAIN获得LOSS(例如请求AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK 并不 意味着当您失去音频焦点时您将得到一个AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK)。
相反，音频焦点的丢失取决于另一个应用请求的音频焦点类型。因此，例如，如果某些其他应用已请求并被授予 AUDIOFOCUS_GAIN_TRANSIENT，则您的应用将收到 AUDIOFOCUS_LOSS_TRANSIENT(或者，在某些情况下，AUDIOFOCUS_LOSS).
如果您对从GAIN 到LOSS 的映射是如何完成的感兴趣，您可以在FocusRequester.java 中找到它。在 Android 源代码中。
关于Android 音频焦点 (AUDIOFOCUS_GAIN_TRANSIENT_MAY_DUCK)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25133952/