Prevent application from crashing on color detection

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Android

OpenCV

I have an app that uses opencv to detect colors. I placed some code that should detect the color of the pixel touched, to my understanding, but it instead makes the app crash.
How can I fix this issue?
Thanks in advance.

What I have tried:

ImageView imageView = ((ImageView)view);
        final Bitmap bitmap = ((BitmapDrawable)imageView.getDrawable()).getBitmap();
        int px=(int)motionEvent.getX();
        int py=(int)motionEvent.getY();
        int pixel = bitmap.getPixel(px,py);
        red=Color.red(pixel);
        green=Color.green(pixel);
        blue=Color.blue(pixel);