Java MediaPlayer播放和重播问题
我正试图建立一个媒体播放器的声音,可以播放和重放多次希望。但是我在第一次播放音频时遇到了这个错误:Java MediaPlayer播放和重播问题,java,android,android-mediaplayer,Java,Android,Android Mediaplayer,我正试图建立一个媒体播放器的声音,可以播放和重放多次希望。但是我在第一次播放音频时遇到了这个错误: 08-23 14:48:52.613: E/MediaPlayer(24194): error (1, -2147483648) 08-23 14:48:52.613: V/Preschool Basics(24194): Prepare failed.: status=0x1 我调用剧本的代码是: btnPlay = (Button) findViewById(R.id.soundBu
08-23 14:48:52.613: E/MediaPlayer(24194): error (1, -2147483648)
08-23 14:48:52.613: V/Preschool Basics(24194): Prepare failed.: status=0x1
我调用剧本的代码是:
btnPlay = (Button) findViewById(R.id.soundButton);
btnStop = (Button) findViewById(R.id.stopButton);
mpSound = MediaPlayer.create(this, R.raw.a);
mpSound.setLooping(false);
btnPlay.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
//mpSound.start();
Uri uri = Uri.parse("android.resource://com.test.testing/" + R.raw.a);
//Toast.makeText(getApplicationContext(), uri.toString(), 2000).show();
playSong(uri.toString());
btnPlay.setVisibility(View.GONE);
btnStop.setVisibility(View.VISIBLE);
btnStop.setOnClickListener(stopSound);
}
});
View.OnClickListener stopSound = new View.OnClickListener() {
public void onClick(View v) {
if (mpSound != null) {
mpSound.stop();
//mpSound.release();
btnPlay.setVisibility(View.VISIBLE);
btnStop.setVisibility(View.GONE);
}
}
};
playSong()
功能是:
private void playSong(String songPath) {
try {
mpSound.reset();
mpSound.setDataSource(songPath);
mpSound.prepare();
mpSound.start();
//Stop the song and replace button
mpSound.setOnCompletionListener(new OnCompletionListener() {
public void onCompletion(MediaPlayer arg0) {
mpSound.stop();
btnPlay.setVisibility(View.VISIBLE);
btnStop.setVisibility(View.GONE);
}
});
} catch (IOException e) {
Log.v(getString(R.string.app_name), e.getMessage());
}
}
我的声音位于res/raw/a.mp3
当我按下btnPlay
按钮时,显示的是btnStop
按钮,但没有播放任何内容
我希望让用户玩、停、玩等等。我怎样才能做到呢
日志:
08-23 15:41:20.761: E/AndroidRuntime(29438): FATAL EXCEPTION: main
08-23 15:41:20.761: E/AndroidRuntime(29438): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.test.testing/com.test.testing.AlpDisplay}: java.lang.NullPointerException
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2222)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2356)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread.access$600(ActivityThread.java:150)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.os.Handler.dispatchMessage(Handler.java:99)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.os.Looper.loop(Looper.java:137)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread.main(ActivityThread.java:5195)
08-23 15:41:20.761: E/AndroidRuntime(29438): at java.lang.reflect.Method.invokeNative(Native Method)
08-23 15:41:20.761: E/AndroidRuntime(29438): at java.lang.reflect.Method.invoke(Method.java:511)
08-23 15:41:20.761: E/AndroidRuntime(29438): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
08-23 15:41:20.761: E/AndroidRuntime(29438): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
08-23 15:41:20.761: E/AndroidRuntime(29438): at dalvik.system.NativeStart.main(Native Method)
08-23 15:41:20.761: E/AndroidRuntime(29438): Caused by: java.lang.NullPointerException
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.content.ContextWrapper.getResources(ContextWrapper.java:89)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.media.MediaPlayer.create(MediaPlayer.java:824)
08-23 15:41:20.761: E/AndroidRuntime(29438): at com.test.testing.MusicPlayer.<init>(MusicPlayer.java:13)
08-23 15:41:20.761: E/AndroidRuntime(29438): at com.test.testing.AlpDisplay.<init>(AlpDisplay.java:45)
08-23 15:41:20.761: E/AndroidRuntime(29438): at java.lang.Class.newInstanceImpl(Native Method)
08-23 15:41:20.761: E/AndroidRuntime(29438): at java.lang.Class.newInstance(Class.java:1319)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.Instrumentation.newActivity(Instrumentation.java:1054)
08-23 15:41:20.761: E/AndroidRuntime(29438): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2213)
08-23 15:41:20.761: E/AndroidRuntime(29438): ... 11 more
08-23 15:41:20.761:E/AndroidRuntime(29438):致命异常:main
08-23 15:41:20.761:E/AndroidRuntime(29438):java.lang.RuntimeException:无法实例化活动组件信息{com.test.testing/com.test.testing.AlpDisplay}:java.lang.NullPointerException
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2222)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2356)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.ActivityThread.access$600(ActivityThread.java:150)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于android.os.Handler.dispatchMessage(Handler.java:99)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.os.Looper.loop(Looper.java:137)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于android.app.ActivityThread.main(ActivityThread.java:5195)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于java.lang.reflect.Method.Invokenactive(本机方法)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于java.lang.reflect.Method.invoke(Method.java:511)
08-23 15:41:20.761:E/AndroidRuntime(29438):在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:795)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:562)
08-23 15:41:20.761:E/AndroidRuntime(29438):在dalvik.system.NativeStart.main(本机方法)
08-23 15:41:20.761:E/AndroidRuntime(29438):由以下原因引起:java.lang.NullPointerException
08-23 15:41:20.761:E/AndroidRuntime(29438):位于android.content.ContextWrapper.getResources(ContextWrapper.java:89)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.view.ContextThemeWrapper.getResources(ContextThemeWrapper.java:78)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.media.MediaPlayer.create(MediaPlayer.java:824)上
08-23 15:41:20.761:E/AndroidRuntime(29438):在com.test.testing.MusicPlayer(MusicPlayer.java:13)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于com.test.testing.AlpDisplay(AlpDisplay.java:45)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于java.lang.Class.newInstanceImpl(本机方法)
08-23 15:41:20.761:E/AndroidRuntime(29438):位于java.lang.Class.newInstance(Class.java:1319)
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.Instrumentation.newActivity(Instrumentation.java:1054)上
08-23 15:41:20.761:E/AndroidRuntime(29438):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2213)
08-23 15:41:20.761:E/AndroidRuntime(29438):。。。还有11个
这可以做得简单得多。我已经测试了这段代码,它正在工作:
MusicPlayer.java
:
public class MusicPlayer
{
private final int songResId = R.raw.your_song;
private final MediaPlayer mediaPlayer;
public MusicPlayer(Context context)
{
mediaPlayer = MediaPlayer.create(context, songResId);
mediaPlayer.setLooping(true);
}
public void setPlaying(boolean isPlaying)
{
if (isPlaying)
{
mediaPlayer.start();
}
else
{
mediaPlayer.stop();
}
}
public void release()
{
mediaPlayer.stop();
mediaPlayer.release();
}
}
用法(从您的活动中)
:
确保你理解
对于我推荐的歌曲,OGG格式(最大压缩)比MP3格式要好,因为它通常占用的空间少50%,而且质量难以区分。例如,您可以使用转换文件。在我测试代码之前,应该在我的
活动下的代码
哪一部分也会进入停止按钮
?我仅在onDestroy和onBackPressed函数期间调用release()
。如果我想为不同的按钮播放不同的文件,我还可以向MusicLayer传递一些信息吗?在停止按钮侦听器中,您只需调用MusicLayer.setPlaying(false)
(并隐藏您的按钮或其他您想做的事情)。在您的onPause()
方法中,您应该调用release()
,因为您的活动
不再可见,因此您不想播放音乐,您想释放与MediaPlayer
相关的资源。我可以将我的代码发布到网上供您查看吗?我做了更改,但现在我的应用是FC。对不起,强制关闭,它说无法实例化活动。你可以发布。但是我发布的代码确实应该有效。粘贴堆栈跟踪。
MusicPlayer musicPlayer = new MusicPlayer(this);
musicPlayer.setPlaying(true); // play
musicPlayer.setPlaying(false); // stop
musicPlayer.setPlaying(true); // play from the beginning
musicPlayer.release(); // when done using MusicPlayer