App crash at startup

[Spike87]

I just included this repo in my app, and everything seems to work fine up to when I try to run the app. The app crashes instantly at startup as soon as I include any openCV related code. Here an example:

import org.opencv.core.Mat;
public class MainActivity extends AppCompatActivity {

    static {//is any of these actually needed?
        //System.loadLibrary("opencv_java3"); //needed to include OPENCV in the app
        //System.loadLibrary(Core.NATIVE_LIBRARY_NAME);
        //System.loadLibrary();
    }

    // images management
//    Bitmap imageDadBMP  = null;
    Mat imageDadMat     = new Mat(); //un-commenting this line makes the app crash
//    Mat imageDadMatGray = new Mat();

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

    }

}

I included the following line in my build.gradle (app) file:

implementation 'com.github.iamareebjamal:opencv-android:4.1.1-contrib'

and the following one in the build.gradle (project) file:

maven { url 'https://jitpack.io' }

NDK version: 21.1.6352462

[MathewSachin]

I'm using 4.3.0 (not contrib). This works for me:

import org.opencv.android.OpenCVLoader;

and, in the static constructor:

OpenCVLoader.initDebug();

[Spike87]

thank you @MathewSachin . Sorry I forgot to mention that I also solved the issue as you suggest. The following code works for me:

import org.opencv.android.OpenCVLoader;
import org.opencv.core.Mat;

public class MainActivity extends AppCompatActivity {

    static{
        if (!OpenCVLoader.initDebug())
            Log.e("OpenCv", "Unable to load OpenCV");
        else
            Log.d("OpenCv", "OpenCV loaded");
    }

    Mat imageDadMat     = new Mat();

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


    }

    public void myfun(View view){
        Mat imageDadMat     = new Mat();
    }
}

For this to work, the static constructor must be at the beginning of the class, before any variables declaration. Do you confirm this is the case for you as well?

[MathewSachin]

I'm using OpenCV from an Accessibility Service.
So, calling it in either Application.onCreate or AccessibilityService.onServiceConnected work for me

[Spike87]

I tried and it does not work for me when I include the call to OpenCVLoader.initDebug() in the onCreate method.

[MathewSachin]

In your code there is an instance variable imageDadMat which requires OpenCV which would be created before onCreate. Hence the error happens.