Question

I’m developing a simple camera app which is based on the android developers tutorial but my I’m having some issues getting it running.

Here is my LogCat printout.

Now I have traced the NullPointerException to be at line 30 in CameraPreview as you have probably figured out to so the code for CameraPreview is below. I can code in Java and know that a NullPointer is when something is there which hasn’t been created yet but as far as I can tell it has been.

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback{
private SurfaceHolder mHolder;
private Camera mCamera;
private static final String TAG = "Preview";

@SuppressWarnings("deprecation")
public CameraPreview(Context context, Camera camera){
    super(context);
    mCamera = camera;

    //Install callback to get notifications from the app
    mHolder = getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); //deprecated but required for Android Version 3.0 and under
}

public void surfaceCreated(SurfaceHolder holder) {
    //Surface been created now need to tell app where to draw PREVIEW
            try{
                mCamera.setPreviewDisplay(holder);
                mCamera.startPreview();
            }
            catch(IOException e){
                Log.d(TAG, "Camera preview error: " + e.getMessage());
            }

}

Line 30 is the code snippet here – mCamera.setPreviewDisplay(holder);

From what I can tell is that there is an instance of mCamera in the ‘global’ variable private Camera mCamera.

Anyone got any ideas? Sorry its a long question formatted as best I could.

Thanks,
Dan

P.S. I know there are other methods required in this class this is merely the ‘problem snippet’.

Answer 1

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

Looks like camera is getting passed on to CameraPreview as null.

---

Make sure you have these in your Manifest:

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />  
<uses-feature android:name="android.hardware.camera.autofocus" /> 

Also, what’s your getCameraInstance() method?