Zbar with Android : Scanner camera viewport remain inactive and black after showing the url in browser

Question

I need to have a QR scanner in my project. I use ZBar for doing this task. Mainly I did a very small change on the example code given by ZBar git example to do the job. I need to show the scanned result in a browser(if url) or in a dialog(if normal information). Every thing working well with my code given bellow except if I try to show the url after scan a qr code in browser. When I come back to my app from the browser the camera viewport turns black and remain inactive. I tried to get back the camera active to scan another qr code but i failed. I tried to reopen the camera in my onResume() function but that causes error and forcefully exited from the app. Please help me on that issue. ``` package com.myapp; import net.sourceforge.zbar.Config; import net.sourceforge.zbar.Image; import net.sourceforge.zbar.ImageScanner; import net.sourceforge.zbar.Symbol; import net.sourceforge.zbar.SymbolSet; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInt…

Accepted Answer

At last I succeeded to find out the problem of my code and got the solution. When i try to reopen the camera in my `onResume()` method I missed a part. When I create/open a new camera in `onResume()`, the FrameLayout still has my previous camera. So All I do is remove my previous camera from FrameLayout on `onPause()` method and then recreate everything on onResume() method. That solve my problem and now it is working nicely without any error. Here is my `onPause()` and `onResume()` method with the fix. Hope this might help somebody in future.

```
    public void onPause() {
        super.onPause();
        releaseCamera();
        FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview);
        preview.removeView(mPreview);
    }

public void onResume(){
        super.onResume();

try {
            if(mCamera==null){

//setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
            autoFocusHandler = new Handler();
            mCamera = getCameraInstance();
            this.getWindowManager().getDefaultDisplay().getRotation();

scanner = new ImageScanner();
            scanner.setConfig(0, Config.X_DENSITY, 3);
            scanner.setConfig(0, Config.Y_DENSITY, 3);

mPreview = new CameraPreview(this, mCamera, previewCb, autoFocusCB);
            FrameLayout preview = (FrameLayout)findViewById(R.id.cameraPreview);
            preview.addView(mPreview);
            }
        } catch (Exception e) {
            // TODO Auto-generated catch block

}
    }

/** A safe way to get an instance of the Camera object. */
    public static Camera getCameraInstance(){
        Camera c = null;
        try {
            c = Camera.open();
        } catch (Exception e){
        }
        return c;
    }

private void releaseCamera() {
        //Toast.makeText(QRScannerActivity.this, "Paused State", Toast.LENGTH_SHORT).show();
        if (mCamera != null) {
            previewing = false;
            mCamera.setPreviewCallback(null);
            mPreview.getHolder().removeCallback(mPreview);
            mCamera.release();
            mCamera = null;
            mPreview= null;
        }

}
```

Thanks, Sakib

Zbar with Android : Scanner camera viewport remain inactive and black after showing the url in browser

Solution

Problem