Android在UI线程中等待而不冻结它

Question

In my application when user presses a button MediaRecorder starts recording the audio then it continues recording for 50sec and stops automatically.I am starting the recorder from UI Thread but how to wait for 50s without freezing the UI.Here is my code :

MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.setOutputFile(path);
recorder.prepare();
recorder.start();
Thread.sleep(40000);
recorder.stop();
recorder.reset();
recorder.release();

I don't know much about threads.Please help

Answer 1

For something like this, Android provides some tools so you don't need a thread. If you have a handy View object (or if this code is in a View subclass), you can use View.postDelayed(Runnable, long) to schedule a Runnable to execute after a specific delay (in milliseconds).

// need to make recorder final so it can be referenced from anonymous Runnable
final MediaRecorder recorder = new MediaRecorder();
recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
recorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);
recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);
recorder.setOutputFile(path);
recorder.prepare();
recorder.start();
postDelayed(new Runnable() {
    @Override
    public void run() {
        recorder.stop();
        recorder.reset();
        recorder.release();
    }
}, 40000);

If you don't have a handy View , just create a Handler and use it's postDelayed method. It works the same.