Eu tenho seguido rastreamento de pilha

<code>04-17 12:11:56.378: D/ATRecorder(10379): com.htc.autotest.dlib.RecordEngine in loader dalvik.system.DexClassLoader@40528b78
04-17 12:11:56.408: D/WindowManagerImpl(10379): addView, new view, mViews[0]: com.android.internal.policy.impl.PhoneWindow$DecorView@40520738
04-17 12:11:56.428: D/WindowManagerImpl(10379): addView, new view, mViews[1]: android.widget.LinearLayout@40525d00
04-17 12:11:56.438: D/WindowManagerImpl(10379): finishRemoveViewLocked, mViews[1]: android.widget.LinearLayout@40525d00
04-17 12:11:56.718: D/TAG(10379): Error setting camera preview: setPreviewDisplay failed
04-17 12:11:56.748: D/TAG(10379): Error starting camera preview: setPreviewDisplay failed
04-17 12:12:07.558: D/View(10379): onTouchEvent: viewFlags: 0x18004001
04-17 12:12:07.568: D/View(10379): onTouchEvent: isFocusable: true, isFocusableInTouchMode: false, isFocused: false; focusTaken: false
04-17 12:12:07.588: V/MediaRecorderJNI(10379): start
04-17 12:12:07.598: V/MediaRecorderJNI(10379): getMediaRecorder E
04-17 12:12:11.632: V/MediaRecorderJNI(10379): process_media_recorder_call
04-17 12:12:11.642: W/IMediaDeathNotifier(10379): media server died
04-17 12:12:11.642: V/MediaRecorderJNI(10379): JNIMediaRecorderListener::notify
04-17 12:12:11.642: V/MediaRecorderJNI(10379): notify msgType 0x1, ext1 0x64
04-17 12:12:11.642: W/Camera(10379): ICamera died
04-17 12:12:11.642: W/Camera(10379): Camera server died!
04-17 12:12:11.702: E/Camera(10379): Error 100
</code>

e meu código é

<code>public class VideoDemoActivity extends Activity {
/** Called when the activity is first created. */

private Camera mCamera;
private CameraPreview mPreview;
private Button btnCapture,btnStop;

private MediaRecorder mMediaRecorder;
FrameLayout preview;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    initialize();

    if (!checkCameraHardware(this)) {

        Toast.makeText(this, "Camera not found", Toast.LENGTH_SHORT).show();
        finish();

    } else {

        Toast.makeText(this, "Camera found", Toast.LENGTH_SHORT).show();
    }

    mCamera = getCameraInstance();
    mPreview = new CameraPreview(this, mCamera);
    preview.addView(mPreview);

    System.out.println(prepareVideoRecorder());


    btnCapture.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            try {

                mMediaRecorder.start();
            } catch (IllegalStateException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }

    });

    btnStop.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            mMediaRecorder.stop();
        }
    });

}

private void initialize() {
    // TODO Auto-generated method stub

    preview = (FrameLayout) findViewById(R.id.camera_preview);
    btnCapture = (Button) findViewById(R.id.button_capture);
    btnStop = (Button) findViewById(R.id.button_stop);
}

public Camera getCameraInstance(){
    Camera c = null;
    try {
        c = Camera.open(); // attempt to get a Camera instance
    }
    catch (Exception e){

        e.printStackTrace();

    }
    return c; // returns null if camera is unavailable
}

private boolean checkCameraHardware(Context context) {
    if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
        // this device has a camera
        return true;
    } else {
        // no camera on this device
        return false;
    }
}

@Override
protected void onPause() {
    // TODO Auto-generated method stub
    super.onPause();

     releaseMediaRecorder();       // if you are using MediaRecorder, release it first
     releaseCamera();              // release the camera immediately on pause event

}

private boolean prepareVideoRecorder(){


    mMediaRecorder = new MediaRecorder();


    mCamera.unlock();
    mMediaRecorder.setCamera(mCamera);

    mMediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);
    mMediaRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
    mMediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
    mMediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
    mMediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.MPEG_4_SP);
    mMediaRecorder.setOutputFile(getOutputMediaFile().toString());



    try 
    {
        mMediaRecorder.prepare();

    } catch (IllegalStateException e) {
        e.printStackTrace();
        releaseMediaRecorder();
        return false;
    } catch (IOException e) {
        e.printStackTrace();
        releaseMediaRecorder();
        return false;
    }
    return true;
}

private void releaseMediaRecorder(){
    if (mMediaRecorder != null) {
        mMediaRecorder.reset();   // clear recorder configuration
        mMediaRecorder.release(); // release the recorder object
        mMediaRecorder = null;
        mCamera.lock();           // lock camera for later use
    }
}

private void releaseCamera(){
    if (mCamera != null){
        mCamera.release();        // release the camera for other applications
        mCamera = null;
    }
}

private static File getOutputMediaFile(){

     File mediaFile = new File(Environment.getExternalStorageDirectory()+"/video.mp4");

    return mediaFile;
}
</code>

}

Então por favor me ajude a resolver este problema .. Se eu remover o método

prepareVideoRecorder ()

então ele pré-visualiza a câmera corretamente .. mas após a execução deste método ele não mostra nenhuma pré-visualização ... e falha

mMediaRecorder.start ();

pedidos me ajudem ..