Android 切换按钮崩溃

Question

我试图在选中切换按钮时发出间隔播放的声音。单击切换按钮后，我的应用程序不播放任何声音并崩溃。为什么？

代码:

    int bpm;
    double timetw;
    final Button plus = (Button) findViewById(R.id.tempop);
    final Button minus = (Button) findViewById(R.id.tempom);
    final TextView curbpm = (TextView) findViewById(R.id.curbpm);
    final ToggleButton metronomepp = (ToggleButton) findViewById (R.id.metronomepp);
    final MediaPlayer metronome = MediaPlayer.create(this, R.raw.beep);
    bpm=60;
    timetw=((60/bpm)-0.19)*10000;
    curbpm.setText("" + bpm);

    Log.i("Metronome1", ""+metronomepp.isChecked());

    metronomepp.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
             while (metronomepp.isChecked()) {
                    metronomepp.postDelayed(new Runnable() {
                        @Override
                        public void run() {
                             Log.i("Metronome", "InWhile");
                             if (metronome.isPlaying()) {metronome.pause();}
                                metronome.seekTo(0);
                                metronome.setOnSeekCompleteListener(null);
                                metronome.start();
                                metronome.setOnCompletionListener(null)
                        }
                    }, (long) (timetw));
                }
        }
    });

按下切换按钮后的 LogCat:

03-14 22:54:17.094: D/dalvikvm(25418): GC_CONCURRENT freed 101K, 3% free 9518K/9735K, paused 3ms+3ms
03-14 22:54:18.019: D/dalvikvm(25418): GC_CONCURRENT freed 5K, 2% free 9923K/10055K, paused 2ms+2ms
03-14 22:54:19.744: D/dalvikvm(25418): GC_CONCURRENT freed 0K, 2% free 10312K/10439K, paused 1ms+1ms
03-14 22:54:23.039: D/dalvikvm(25418): GC_CONCURRENT freed 0K, 2% free 10759K/10887K, paused 1ms+1ms

Answer 1

您遇到的根本问题是您正在 UI 线程中执行长时间操作。 onCheckedChanged 应该派生一个线程或 Async 类，这将发出滴答声直到停止。最好还是有一个线程来发出滴答声，您可以从 onCheckedChanged 打开和关闭该滴答声。

@Torben-Kohlmeier 对您的问题的回答中可能给出了实现此目的的最佳方法，我对其进行了编辑以明确它如何适合您的代码。