如何使用MediaPlayer（android）同時播放兩個或更多音頻剪輯

Question

我和我的朋友正在創建一個android應用。 我們幾乎做到了...該應用程序在第一次運行時將同時播放兩種聲音，但在第二次運行時它將引發一些錯誤並達到ANR狀態。 如何解決這個問題？ 檢查下面的logcat和代碼。

碼

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements OnClickListener,Runnable {

    boolean mBound = false;
    Button btn1,btn2;
    Button btn3;
    Button btn4;
    MediaPlayer yourStereo;

    MediaPlayer myStereo;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
         btn1=(Button)findViewById(R.id.a_button);
         btn2=(Button)findViewById(R.id.b_button);
         btn3=(Button)findViewById(R.id.c_button);
         btn4=(Button)findViewById(R.id.d_button);


        btn1.setOnClickListener(this);
        myStereo = MediaPlayer.create(this, R.raw.brb);
        btn3.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                btn3.setVisibility(Button.GONE);
                btn4.setVisibility(Button.VISIBLE);
                // TODO Auto-generated method stub



                        try {
                            myStereo.prepare();
                        } catch (IllegalStateException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }
                        myStereo.setLooping(true);
                        myStereo.start();
                        myStereo.setOnCompletionListener(new OnCompletionListener() {

                            @Override
                            public void onCompletion(MediaPlayer mp) {
                                // TODO Auto-generated method stub
                                myStereo.setLooping(true);
                                myStereo.release();
                                try {
                                    myStereo.prepare();
                                } catch (IllegalStateException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                } catch (IOException e) {
                                    // TODO Auto-generated catch block
                                    e.printStackTrace();
                                }
                                myStereo.start();
                            }
                        });
                        // pause music here

                        btn4.setOnClickListener(new View.OnClickListener() {

                            @Override
                            public void onClick(View v) {
                                // TODO Auto-generated method stub
                                myStereo.stop();
                                btn4.setVisibility(Button.GONE);
                                btn3.setVisibility(Button.VISIBLE);

                            }
                        });
            }
        });



    }

    @Override
    public void onClick(View arg0) {
            // play music here
            btn1.setVisibility(Button.GONE);
            btn2.setVisibility(Button.VISIBLE);
            // TODO Auto-generated method stub
            yourStereo = MediaPlayer.create(this, R.raw.pl);
            yourStereo.setLooping(true);
            try {
                yourStereo.prepare();
            } catch (IllegalStateException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            } catch (IOException e1) {
                // TODO Auto-generated catch block
                e1.printStackTrace();
            }
                    yourStereo.start();
                    yourStereo.setOnCompletionListener(new OnCompletionListener() {

                        @Override
                        public void onCompletion(MediaPlayer mp) {
                            // TODO Auto-generated method stub
                            yourStereo.setLooping(true);
                            yourStereo.release();
                            try {
                                yourStereo.prepare();
                            } catch (IllegalStateException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            } catch (IOException e) {
                                // TODO Auto-generated catch block
                                e.printStackTrace();
                            }
                            yourStereo.start();
                        }
                    });
            // pause music here

            btn2.setOnClickListener(new View.OnClickListener() {

                @Override
                public void onClick(View v) {
                    // TODO Auto-generated method stub
                    yourStereo.stop();
                    btn2.setVisibility(Button.GONE);
                    btn1.setVisibility(Button.VISIBLE);

                }
            });
    }


    @Override
    public void run() {
        // TODO Auto-generated method stub

    }

}

logcat的

07-08 11:44:17.245: W/System.err(2659): java.lang.IllegalStateException
07-08 11:44:17.261: W/System.err(2659):     at android.media.MediaPlayer.prepare(Native Method)
07-08 11:44:17.261: W/System.err(2659):     at com.example.sleepsimulator.MainActivity$1.onClick(MainActivity.java:49)
07-08 11:44:17.269: W/System.err(2659):     at android.view.View.performClick(View.java:2485)
07-08 11:44:17.269: W/System.err(2659):     at android.view.View$PerformClick.run(View.java:9080)
07-08 11:44:17.269: W/System.err(2659):     at android.os.Handler.handleCallback(Handler.java:587)
07-08 11:44:17.269: W/System.err(2659):     at android.os.Handler.dispatchMessage(Handler.java:92)
07-08 11:44:17.269: W/System.err(2659):     at android.os.Looper.loop(Looper.java:130)
07-08 11:44:17.269: W/System.err(2659):     at android.app.ActivityThread.main(ActivityThread.java:3687)
07-08 11:44:17.269: W/System.err(2659):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 11:44:17.269: W/System.err(2659):     at java.lang.reflect.Method.invoke(Method.java:507)
07-08 11:44:17.269: W/System.err(2659):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
07-08 11:44:17.269: W/System.err(2659):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
07-08 11:44:17.269: W/System.err(2659):     at dalvik.system.NativeStart.main(Native Method)
07-08 11:44:20.534: W/KeyCharacterMap(2659): Can't open keycharmap file
07-08 11:44:20.534: W/KeyCharacterMap(2659): Error loading keycharmap file
07-08 11:44:20.534: W/KeyCharacterMap(2659): Using default keymap
07-08 11:44:26.636: W/System.err(2659): java.io.IOException: Prepare failed.: status=0xFFFFFF8E
07-08 11:44:26.636: W/System.err(2659):     at android.media.MediaPlayer.prepare(Native Method)
07-08 11:44:26.636: W/System.err(2659):     at com.example.sleepsimulator.MainActivity$1.onClick(MainActivity.java:49)
07-08 11:44:26.636: W/System.err(2659):     at android.view.View.performClick(View.java:2485)
07-08 11:44:26.636: W/System.err(2659):     at android.view.View$PerformClick.run(View.java:9080)
07-08 11:44:26.636: W/System.err(2659):     at android.os.Handler.handleCallback(Handler.java:587)
07-08 11:44:26.636: W/System.err(2659):     at android.os.Handler.dispatchMessage(Handler.java:92)
07-08 11:44:26.636: W/System.err(2659):     at android.os.Looper.loop(Looper.java:130)
07-08 11:44:26.636: W/System.err(2659):     at android.app.ActivityThread.main(ActivityThread.java:3687)
07-08 11:44:26.636: W/System.err(2659):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 11:44:26.636: W/System.err(2659):     at java.lang.reflect.Method.invoke(Method.java:507)
07-08 11:44:26.636: W/System.err(2659):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
07-08 11:44:26.636: W/System.err(2659):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
07-08 11:44:26.636: W/System.err(2659):     at dalvik.system.NativeStart.main(Native Method)
07-08 11:44:26.636: E/MediaPlayer(2659): start called in state 64
07-08 11:44:26.636: E/MediaPlayer(2659): error (-38, 0)
07-08 11:44:34.643: E/MediaPlayer(2659): stop called in state 0
07-08 11:44:34.643: E/MediaPlayer(2659): error (-38, 0)
07-08 11:44:34.643: E/MediaPlayer(2659): Error (-38,0)
07-08 11:44:34.651: W/System.err(2659): java.lang.IllegalStateException
07-08 11:44:34.675: W/System.err(2659):     at android.media.MediaPlayer.prepare(Native Method)
07-08 11:44:34.675: W/System.err(2659):     at com.example.sleepsimulator.MainActivity$1$1.onCompletion(MainActivity.java:67)
07-08 11:44:34.675: W/System.err(2659):     at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:1475)
07-08 11:44:34.675: W/System.err(2659):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-08 11:44:34.675: W/System.err(2659):     at android.os.Looper.loop(Looper.java:130)
07-08 11:44:34.675: W/System.err(2659):     at android.app.ActivityThread.main(ActivityThread.java:3687)
07-08 11:44:34.675: W/System.err(2659):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 11:44:34.675: W/System.err(2659):     at java.lang.reflect.Method.invoke(Method.java:507)
07-08 11:44:34.675: W/System.err(2659):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
07-08 11:44:34.675: W/System.err(2659):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
07-08 11:44:34.675: W/System.err(2659):     at dalvik.system.NativeStart.main(Native Method)
07-08 11:44:34.675: W/dalvikvm(2659): threadid=1: thread exiting with uncaught exception (group=0x40018578)
07-08 11:44:34.683: E/AndroidRuntime(2659): FATAL EXCEPTION: main
07-08 11:44:34.683: E/AndroidRuntime(2659): java.lang.IllegalStateException
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.media.MediaPlayer._start(Native Method)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.media.MediaPlayer.start(MediaPlayer.java:950)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at com.example.sleepsimulator.MainActivity$1$1.onCompletion(MainActivity.java:75)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.media.MediaPlayer$EventHandler.handleMessage(MediaPlayer.java:1475)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.os.Looper.loop(Looper.java:130)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at android.app.ActivityThread.main(ActivityThread.java:3687)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at java.lang.reflect.Method.invokeNative(Native Method)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at java.lang.reflect.Method.invoke(Method.java:507)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:867)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:625)
07-08 11:44:34.683: E/AndroidRuntime(2659):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

您收到的錯誤是由於在onCompletionListener調用.release()然后調用.release() .prepare()

.release()釋放所有資源，並且實際上僅在您不想再使用MediaPlayer時才應調用它，例如，在應用程序退出時。

http://developer.android.com/reference/android/media/MediaPlayer.html#release（）

因此您的來電.prepare()后.release()失敗，因為它不知道哪些准備。

如果您只是再次播放同一文件，則可以再次在onCompletion上調用.start() 。 我相信它將重新開始。 無需釋放並再次准備。

同樣，如果您使用的是.create() ，則根本不需要調用.prepare() ，因為它已經處於准備狀態。

http://developer.android.com/reference/android/media/MediaPlayer.html#create(android.content.Context、android.net.Uri、android.view.SurfaceHolder）