Android應用程序拍攝一張照片後崩潰？

Question

我正在嘗試製作相機應用程序，但只要我拍照，相機預覽就會停止，如果再次單擊我的捕捉按鈕，應用程序就會崩潰。這可能是什麼原因？ 我的錯誤日誌：

07-04 17:31:36.278 3943-3943/com.asim.spycamera E/AndroidRuntime﹕ FATAL EXCEPTION: main 
Process: com.asim.spycamera, PID: 3943 
java.lang.RuntimeException: takePicture failed 
     at android.hardware.Camera.native_takePicture(Native Method) 
     at android.hardware.Camera.takePicture(Camera.java:1436) 
     at android.hardware.Camera.takePicture(Camera.java:1381) 
     at com.asim.spycamera.MainActivity$2.onClick(MainActivity.java:91) 
     at android.view.View.performClick(View.java:4780) 
     at android.view.View$PerformClick.run(View.java:19866) 
     at android.os.Handler.handleCallback(Handler.java:739) 
     at android.os.Handler.dispatchMessage(Handler.java:95) 
     at android.os.Looper.loop(Looper.java:135) 
     at android.app.ActivityThread.main(ActivityThread.java:5254) 
     at java.lang.reflect.Method.invoke(Native Method) 
     at java.lang.reflect.Method.invoke(Method.java:372) 
     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903) 
     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698) 

我的主要活動代碼：

public class MainActivity extends ActionBarActivity { 

private Camera mCamera; 
private CameraPreview mPreview; 
public static final String TAG = "MAIN-TAG"; 
public static final int MEDIA_TYPE_IMAGE = 1; 
public static final int MEDIA_TYPE_VIDEO = 2; 


private Camera.PictureCallback mPicture = new Camera.PictureCallback() { 

    @Override 
    public void onPictureTaken(byte[] data, Camera camera) { 

     File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE); 
     if (pictureFile == null){ 
      mPreview.safeToTakePicture = true; 
      Log.d(TAG, "Error creating media file, check storage permissions "); 
      return; 
     } 

     try { 
      FileOutputStream fos = new FileOutputStream(pictureFile); 
      fos.write(data); 
      fos.close(); 
     } catch (FileNotFoundException e) { 
      Log.d(TAG, "File not found: " + e.getMessage()); 
     } catch (IOException e) { 
      Log.d(TAG, "Error accessing file: " + e.getMessage()); 
     } 
     mPreview.safeToTakePicture = true; 
    } 
}; 

/** A safe way to get an instance of the Camera object. */ 
public static Camera getCameraInstance(){ 
    Camera c = null; 
    try { 
     c = Camera.open(); // attempt to get a Camera instance 
    } 
    catch (Exception e){ 
     // Camera is not available (in use or does not exist) 
    } 
    return c; // returns null if camera is unavailable 
} 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    // Create an instance of Camera 
    mCamera = getCameraInstance(); 

    // Create our Preview view and set it as the content of our activity. 
    mPreview = new CameraPreview(this, mCamera); 
    FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview); 
    preview.addView(mPreview); 

    // Add a listener to the Capture button 
    Button captureButton = (Button) findViewById(R.id.button_capture); 
    captureButton.setOnClickListener(
      new View.OnClickListener() { 
       @Override 
       public void onClick(View v) { 
        // get an image from the camera 
        if (mPreview.safeToTakePicture) { 
         mCamera.takePicture(null, null, mPicture); 
         mPreview.safeToTakePicture = false; 
        } 
       } 
      } 
    ); 

} 

我對CameraPreview類代碼

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback { 

private SurfaceHolder mHolder; 
private Camera mCamera; 
public static final String TAG = "CAMERA-TAG"; 
public boolean safeToTakePicture = false; 

public CameraPreview(Context context, Camera camera) { 
    super(context); 
    mCamera = camera; 

    // Install a SurfaceHolder.Callback so we get notified when the 
    // underlying surface is created and destroyed. 
    mHolder = getHolder(); 
    mHolder.addCallback(this); 
    // deprecated setting, but required on Android versions prior to 3.0 
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); 
} 

public void surfaceCreated(SurfaceHolder holder) { 
    // The Surface has been created, now tell the camera where to draw the preview. 
    try { 
     mCamera.setPreviewDisplay(holder); 
     mCamera.startPreview(); 
    } catch (IOException e) { 
     Log.d(TAG, "Error setting camera preview: " + e.getMessage()); 
    } 
} 

public void surfaceDestroyed(SurfaceHolder holder) { 
    // empty. Take care of releasing the Camera preview in your activity. 
} 

public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { 
    // If your preview can change or rotate, take care of those events here. 
    // Make sure to stop the preview before resizing or reformatting it. 

    if (mHolder.getSurface() == null){ 
     // preview surface does not exist 
     return; 
    } 

    // stop preview before making changes 
    try { 
     mCamera.stopPreview(); 
    } catch (Exception e){ 
     // ignore: tried to stop a non-existent preview 
    } 

    // set preview size and make any resize, rotate or 
    // reformatting changes here 

    // start preview with new settings 
    try { 
     mCamera.setPreviewDisplay(mHolder); 
     mCamera.startPreview();; 
     safeToTakePicture = true; 

    } catch (Exception e){ 
     Log.d(TAG, "Error starting camera preview: " + e.getMessage()); 
    } 
} 

Answer 1

在onPictureTaken()你應該明確地調用Camera.startPreview()（見https://stackoverflow.com/a/10490957/192373）。