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当我按下一个按钮时，我的应用程序应该会启动一段时间，然后在我单击同一个按钮时停止它。应用程序进入并播放一次声音然后崩溃。为什么？

Java代码：

    metronomepp.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            if (ms==0) {ms=1;}
            while (ms == 1) {
                if (metronome.isPlaying()) {metronome.pause();}
                metronome.seekTo(0);
                metronome.setOnSeekCompleteListener(null);
                metronome.start();
                metronome.setOnCompletionListener(null);
                try {
                    wait ((long) timetw);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                metronomepp.setOnClickListener(new OnClickListener() {
                    public void onClick(View v) {
                        Log.i("Metronome", "InWhile1");
                        ms=0;
                    }
                });
            }
        }
    });

按下按钮后的 LogCat：

03-14 19:10:30.584: I/Metronome clicked(25448): 1
03-14 19:10:30.584: I/Metronome(25448): InWhile
03-14 19:10:30.584: V/MediaPlayer(25448): isPlaying: 0
03-14 19:10:30.584: V/MediaPlayer-JNI(25448): isPlaying: 0
03-14 19:10:30.584: V/MediaPlayer-JNI(25448): seekTo: 0(msec)
03-14 19:10:30.584: V/MediaPlayer(25448): seekTo 0
03-14 19:10:30.584: V/MediaPlayer(25448): getDuration
03-14 19:10:30.584: V/MediaPlayer(25448): message received msg=4, ext1=0, ext2=0
03-14 19:10:30.589: V/MediaPlayer(25448): Received seek complete
03-14 19:10:30.589: V/MediaPlayer(25448): All seeks complete - return to regularly scheduled program
03-14 19:10:30.589: V/MediaPlayer(25448): callback application
03-14 19:10:30.589: V/MediaPlayer(25448): back from callback
03-14 19:10:30.589: V/MediaPlayer-JNI(25448): start
03-14 19:10:30.589: V/MediaPlayer(25448): start
03-14 19:10:30.619: D/AndroidRuntime(25448): Shutting down VM
03-14 19:10:30.619: W/dalvikvm(25448): threadid=1: thread exiting with uncaught exception (group=0x40c581f8)
03-14 19:10:30.624: E/AndroidRuntime(25448): FATAL EXCEPTION: main
03-14 19:10:30.624: E/AndroidRuntime(25448): java.lang.IllegalMonitorStateException: object not locked by thread before wait()
03-14 19:10:30.624: E/AndroidRuntime(25448):    at java.lang.Object.wait(Native Method)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at java.lang.Object.wait(Object.java:401)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at com.example.guitartools.MetronomeActivity$3.onClick(MetronomeActivity.java:72)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.view.View.performClick(View.java:3627)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.view.View$PerformClick.run(View.java:14329)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.os.Handler.handleCallback(Handler.java:605)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.os.Handler.dispatchMessage(Handler.java:92)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.os.Looper.loop(Looper.java:137)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at android.app.ActivityThread.main(ActivityThread.java:4511)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at java.lang.reflect.Method.invokeNative(Native Method)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at java.lang.reflect.Method.invoke(Method.java:511)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:980)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:747)
03-14 19:10:30.624: E/AndroidRuntime(25448):    at dalvik.system.NativeStart.main(Native Method)
03-14 19:10:30.969: V/MediaPlayer(25448): message received msg=2, ext1=0, ext2=0
03-14 19:10:30.969: V/MediaPlayer(25448): playback complete
03-14 19:10:30.969: V/MediaPlayer(25448): callback application
03-14 19:10:30.969: V/MediaPlayer(25448): back from callback
4

2 回答 2

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您可能想尝试使用runOnUiThread()。你需要一个单独的线程。你不希望你的UI线程sleep或wait

这是一个相关的SO问题

于 2013-03-14T18:44:42.343 回答
0

你不应该阻塞主线程：

at java.lang.Object.wait(Native Method)
...
at android.app.ActivityThread.main(ActivityThread.java:4511)

Android 的推荐方法是使用 Handler 和 Runnable，如下所示：

metronomepp.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        if (ms==0) {ms=1;}

        if (ms==1) {
            metronomepp.postDelayed(new Runnable() {
                @Override
                public void run() {
                    metronomepp.setOnClickListener(new OnClickListener() {
                        public void onClick(View v) {
                            Log.i("Metronome", "InWhile1");
                            ms=0;
                        }
                    });
                }
            }, timetw);
        }

        while (ms == 1) {
            if (metronome.isPlaying()) {metronome.pause();}
            metronome.seekTo(0);
            metronome.setOnSeekCompleteListener(null);
            metronome.start();
            metronome.setOnCompletionListener(null);
        }
    }
});

postDelayed()timetw在第二个参数 ( )中传递的毫秒数之后执行 Runnable 中的代码。

于 2013-03-14T18:55:17.770 回答