Question

我的Android应用在按下一组特定的Buttons后崩溃。基本上，Activity有两个Buttons。一个播放声音，另一个播放另一个Activity。但是在使用后退按钮返回并再次按下声音Button之后，它将使应用程序崩溃。我不确定为什么Button第一次起作用。我以为我必须重置MediaPlayer但它仍然会崩溃。

我的Activity：

public class Tables1 extends Activity {

    MediaPlayer mysound;
    protected boolean active = true;
    protected int splashtime = 17000;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.twotime1);
        mysound = MediaPlayer.create(Tables1.this, R.raw.two1);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        mysound.stop();
        mysound.reset();
        mysound.release();
        mysound = null;
    }

    public void listen(View view) {

        mysound.setOnCompletionListener(new OnCompletionListener() {
            public void onCompletion(MediaPlayer mysound) {
                mysound.release();
            }

        });
        mysound.start();
    }

    public void Next(View view) {
        if (mysound.isPlaying()) {
            mysound.stop();
            mysound.reset();
        } else {
            Log.d("Exercise", "not working ");
        }

        Intent i = new Intent();
        i.setClassName("com.example", "com.example.twotimes.Exercise1");
        startActivity(i);
    }

    public void back(View view) {
        if (mysound.isPlaying()) {
            mysound.stop();
        }

        Intent i = new Intent();
        i.setClassName("com.example", "com.example.timestableseasy.Menu2");
        startActivity(i);
    }
}

logcat的：

05-30 15:00:35.954: E/AndroidRuntime(31572): FATAL EXCEPTION: main
05-30 15:00:35.954: E/AndroidRuntime(31572): java.lang.IllegalStateException: Could not execute method of the activity
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.view.View$1.onClick(View.java:3814)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.view.View.performClick(View.java:4421)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.view.View$PerformClick.run(View.java:17903)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.os.Handler.handleCallback(Handler.java:730)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.os.Handler.dispatchMessage(Handler.java:92)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.os.Looper.loop(Looper.java:213)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.app.ActivityThread.main(ActivityThread.java:5225)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at java.lang.reflect.Method.invokeNative(Native Method)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at java.lang.reflect.Method.invoke(Method.java:525)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:741)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:557)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at dalvik.system.NativeStart.main(Native Method)
05-30 15:00:35.954: E/AndroidRuntime(31572): Caused by: java.lang.reflect.InvocationTargetException
05-30 15:00:35.954: E/AndroidRuntime(31572):    at java.lang.reflect.Method.invokeNative(Native Method)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at java.lang.reflect.Method.invoke(Method.java:525)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.view.View$1.onClick(View.java:3809)
05-30 15:00:35.954: E/AndroidRuntime(31572):    ... 11 more
05-30 15:00:35.954: E/AndroidRuntime(31572): Caused by: java.lang.IllegalStateException
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.media.MediaPlayer._start(Native Method)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at android.media.MediaPlayer.start(MediaPlayer.java:1082)
05-30 15:00:35.954: E/AndroidRuntime(31572):    at com.example.twotimes.Tables1.listen(Tables1.java:52)
05-30 15:00:35.954: E/AndroidRuntime(31572):    ... 14 more

Answer 1

来自Android文档：

“IllegalStateException：内部播放器引擎尚未发生已初始化或已被释放。“

当您通过Activity转到新的Intent时，之前的Activity会通过onDestroy()方法：

mysound.stop();
mysound.reset();
mysound.release();

用户按下后退按钮后，不会重新创建mysound。尝试将listen()方法更改为：

public void listen(View view) {
    mysound = MediaPlayer.create(Tables1.this, R.raw.two1);
    mysound.setOnCompletionListener(new OnCompletionListener() {
        public void onCompletion(MediaPlayer mysound) {
            mysound.release();
        }

    });
    mysound.start();
}

Android：应用程序在返回并按下按钮后崩溃

1 个答案: