OpenCV initialisation issue on Android

Question

I use OpenCV on Android and i don't understand why i can't instantiate a simple Mat. I think I don't do right implementation of OpenCV with the BaseLoaderCallback.

public class MainActivity extends Activity {

private final String TAG = "Main activity";

private BaseLoaderCallback mOpenCVCallBack = new BaseLoaderCallback(this) {
    @Override
    public void onManagerConnected(int status) {
       switch (status) {
           case LoaderCallbackInterface.SUCCESS:
           {
          Log.i(TAG, "OpenCV loaded successfully");             
            setContentView(R.layout.activity_main);
           //Mat image = new Mat(); // <--- problem here
           } break;
           default:
           {
          super.onManagerConnected(status);
           } break;
       }
    }
};

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

    public void onResume()
    {
        super.onResume();
        OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_3, this, mOpenCVCallBack);
    }

My LogCat is only a FatalSignal 11 (SIGSEV).

EDIT : After many modifications, this is now works and i don't know why but thanks.

Try making the Mat variable global.

Karthik Balakrishnan
– Karthik Balakrishnan

2013-05-15 20:10:44 +00:00
Commented May 15, 2013 at 20:10 — Karthik Balakrishnan
– Karthik Balakrishnan, Commented May 15, 2013 at 20:10

Karthik Balakrishnan · Accepted Answer · 2013-05-15 20:14:27Z

1

Try this piece of code:

Mat m; private static final String TAG = "OCVSample::Activity";

  private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
    switch (status) {
        case LoaderCallbackInterface.SUCCESS:
        {
            Log.i(TAG, "OpenCV loaded successfully");
            m=new Mat();
        } break;
        default:
        {
            super.onManagerConnected(status);
        } break;
    }
}
};

OpenCV functions such as Mat have to be invoked in either a thread or AsyncTask or from within an OpenCV function.

answered May 15, 2013 at 20:14

Karthik Balakrishnan

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