Android MediaPlayer - setDataSource 和 Release - IllegalStateException

Question

我自己编写了 MediaPlayer class 来播放特定路径下的文件以及播放 assets 文件夹中的文件。这是 class:

public class CMediaPlayer extends MediaPlayer{

public void play(String audioPath){

   this.setOnCompletionListener(new OnCompletionListener() {
        @Override
        public void onCompletion(MediaPlayer mp) {
            mp.release();
        }
    });

    File f = new File(audioPath);
    if(f.exists()){
        try{
            FileInputStream fis = new FileInputStream(f);
            FileDescriptor fileD = fis.getFD();
            this.setDataSource(fileD);
            this.prepare();

        }catch(IOException e){

        }
       this.start();
}
}

    public void play(AssetFileDescriptor descriptor){

        this.setOnCompletionListener(new OnCompletionListener() {
            @Override
            public void onCompletion(MediaPlayer mp) {
               mp.release();
            }
        });
        try {
            this.setDataSource(descriptor.getFileDescriptor(), descriptor.getStartOffset(), descriptor.getLength());
            descriptor.close();
            this.prepare();
        }catch (IOException e){

        }
        this.start();
    }

}

我想用来自 activity 的 class 播放多种声音。这是我的代码：

public class playGame extends Activity {

//a lot of variables

    CMediaPlayer mediaPlayer; //declare my mediaplayer

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK ) {
            //release??????
            Intent myIntent = new Intent(getBaseContext(), startView.class);
            startActivity(myIntent);
        }
        return super.onKeyDown(keyCode, event);
    }

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_play_question2);

        mediaPlayer = new CMediaPlayer(); //define my mediaplayer

       //stuff
    }

    //more variables

    public void playQuestion(File question){

        //stuff

        TextView myTextView = (TextView) findViewById(R.id.textViewQuestion);
        //stuff
        myTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
            mediaPlayer.play(pathSoundQuestion); //play sound when clicked
            }
        });

    //stuff

        myImageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               mediaPlayer.play(pathSoundQuestion); //play sound when clicked
            }
        });

        //stuff
        mediaPlayer.play(pathSoundQuestion); //plays sound immediatly, first played sound (works fine)

        //button1
        Button myButton = (Button) findViewById(R.id.button1);
        //stuff
        myButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(lastClickedButton == v){
                   //stuff
                    return;
                }
                //stuff
                mediaPlayer.play(pathAudio1); //play sound when clicked (error)
            }
        });

        //button2
        myButton = (Button) findViewById(R.id.button2);
       //stuff
        myButton.setOnClickListener(new Button.OnClickListener() {
            @Override
            public void onClick(View v) {
                if(lastClickedButton == v){
                    //stuff
                    return;
                }
                //stuff
                mediaPlayer.play(pathAudio2); //play sound, same problem
            }
        });

       //goes on like this some more times...
    }

    public void logIn(View v, String right){
        //stuff

        if(right.equals("true")){
           //stuff
            try {
                AssetFileDescriptor descriptor = getAssets().openFd("Right");
                mediaPlayer.play(descriptor); //play sound from assets
                Intent myIntent = new Intent(getApplication(), playGame.class);
                startActivity(myIntent);
            }catch (IOException e){
            }
        }else{
          //stuff
            try {
                AssetFileDescriptor descriptor = getAssets().openFd("Wrong");
                mediaPlayer.play(descriptor); //play sound from assets
                Intent myIntent = new Intent(getApplication(), playGame.class);
                startActivity(myIntent);
            }catch (IOException e){
            }
        }
    }
}

应用程序播放我在代码中的评论中提到的第一个声音。当我单击应该启动另一个声音的按钮时，我收到以下错误：

03-16 23:07:38.478  13646-13646/com.example.cello.myownquiz E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.IllegalStateException
            at android.media.MediaPlayer.setDataSource(Native Method)
            at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1005)

我的 MediaPlayer class 是否正常，或者我是否遗漏了一些东西，具体取决于状态？这是 class 调用 release 的唯一位置还是我也必须把它放在我的 activity 中的某个地方？

有人看到我的错误了吗？ mediaPlayer的这个问题花了我一整天的时间，希望你能帮助我...

Answer 1

将 mp.release(); 更改为 mp.reset();

public无效重置()

Resets the MediaPlayer to its uninitialized state. After calling this method, you will have to initialize it again by setting the data source and calling prepare().

public无效释放()

Releases resources associated with this MediaPlayer object. It is considered good practice to call this method when you're done using the MediaPlayer. In particular, whenever an Activity of an application is paused (its onPause() method is called), or stopped (its onStop() method is called), this method should be invoked to release the MediaPlayer object, unless the application has a special need to keep the object around. In addition to unnecessary resources (such as memory and instances of codecs) being held, failure to call this method immediately if a MediaPlayer object is no longer needed may also lead to continuous battery consumption for mobile devices, and playback failure for other applications if no multiple instances of the same codec are supported on a device. Even if multiple instances of the same codec are supported, some performance degradation may be expected when unnecessary multiple instances are used at the same time.

你需要把物品放在身边。

你可以通过简单的方式做到这一点

        MediaPlayer mediaPlayer = new MediaPlayer();
        mediaPlayer.setDataSource(context, ringtone);
        mediaPlayer.setAudioStreamType(AudioManager.STREAM_MEDIA);
        mediaPlayer.prepare();
        mediaPlayer.start();

Answer 2

我也有这个问题，但我用过：

public void play(String name){
    try {
        AssetFileDescriptor afd = getAssets().openFd(name);
        if(myPlayer == null){
            myPlayer = new MediaPlayer();
        }
        myPlayer.setDataSource(afd.getFileDescriptor(), afd.getStartOffset(), afd.getLength());
        myPlayer.prepare();
        myPlayer.start();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

并停止：

public void stopPlayer(){
    if(myPlayer!= null && myPlayer.isPlaying()){
        myPlayer.stop();
        myPlayer = null;
    }else{
        myPlayer = null;
    }
}

Android MediaPlayer - setDataSource 和 Release - IllegalStateException

Android MediaPlayer - setDataSource and Release - IllegalStateException

android

android-mediaplayer