Failed to start startPreview camera

Question

I am creating a camera application, but I have problems with startPreview , it sends me:

 java.lang.RuntimeException: startPreview failed 

here is my camera. Activity:

 public class CameraActivity extends Activity { private Camera mCamera; private CameraPreview mPreview; private Target_Frame targetFrame; @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.camera_layout); mCamera=getCameraInstance(); mPreview=new CameraPreview(this, mCamera); FrameLayout preview=(FrameLayout)findViewById(R.id.camera_preview); preview.addView(mPreview); } /** Check if this device has a camera only if not specified in the manifest */ public 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; } } /** 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 } /**Check if the device has flash*/ public boolean checkFlash(Context context){ if(context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FLASH)){ //the device has flash return true; }else{ //no flash return false; } } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); releaseCamera(); } @Override protected void onPause() { // TODO Auto-generated method stub super.onPause(); releaseCamera(); } @Override protected void onResume() { // TODO Auto-generated method stub super.onResume(); //Test if i have to put all this code like in onCreate if(mCamera!=null){ return; } mCamera=getCameraInstance(); if(mPreview!=null){ return; } mPreview=new CameraPreview(this, mCamera); FrameLayout preview=(FrameLayout)findViewById(R.id.camera_preview); preview.addView(mPreview); } private void releaseCamera(){ if (mCamera != null){ mCamera.release(); // release the camera for other applications mCamera = null; } }} 

And here is my SurfaceView code:

 public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback { private static final String TAG = "CameraPreview"; private SurfaceHolder mHolder; private Camera mCamera; 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 Parameters parameters= mCamera.getParameters(); parameters.setPreviewSize(w, h); mCamera.setParameters(parameters); // start preview with new settings try { mCamera.setPreviewDisplay(mHolder); mCamera.startPreview(); } catch (Exception e){ Log.d(TAG, "Error starting camera preview: " + e.getMessage()); } } } 

And here is my error log:

 12-01 13:17:01.135: E/AndroidRuntime(1161): FATAL EXCEPTION: main 12-01 13:17:01.135: E/AndroidRuntime(1161): java.lang.RuntimeException: startPreview 12-01 13:17:01.135: E/AndroidRuntime(1161): at com.example.prueba.CameraPreview.surfaceCreated(CameraPreview.java:36) 

Answer 1

I decided to remove some lines in surfaceChanged

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

Therefore, the error should be in one of the following lines:

 Parameters parameters= mCamera.getParameters(); parameters.setPreviewSize(w, h); mCamera.setParameters(parameters); 

Can someone explain to me what was wrong with these lines?

Answer 2

Is (w, h) a valid preview size for your camera?

You can use mCamera.getParameters().getSupportedPreviewSizes() to get all valid preview sizes.

Answer 3

Late, but if someone is looking for an answer

Variables w and h are not optimal preview sizes. You can get optimal preview sizes using the function

 public static Camera.Size getOptimalPreviewSize(List<Camera.Size> sizes, int w, int h) { final double ASPECT_TOLERANCE = 0.1; double targetRatio=(double)h / w; if (sizes == null) return null; Camera.Size optimalSize = null; double minDiff = Double.MAX_VALUE; int targetHeight = h; for (Camera.Size size : sizes) { double ratio = (double) size.width / size.height; if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; if (Math.abs(size.height - targetHeight) < minDiff) { optimalSize = size; minDiff = Math.abs(size.height - targetHeight); } } if (optimalSize == null) { minDiff = Double.MAX_VALUE; for (Camera.Size size : sizes) { if (Math.abs(size.height - targetHeight) < minDiff) { optimalSize = size; minDiff = Math.abs(size.height - targetHeight); } } } return optimalSize; } 

and you can call the function using

 public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { .. size=getOptimalPreviewSize(parameters.getSupportedPreviewSizes(), w, h); parameters.setPreviewSize(size.getWidth(), size.getHeight()); .. } 

Answer 4

I had this error, and this is because I did not call releaseCamera in onPause when I first started my application.
After reboot, everything works fine ^^

Answer 5

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