Android: OpenCV: imwrite always returns false and fails to write

Question

This code used to work but on Android 4.2 and OpenCV 2.4.4 it fails, but I don\'t know why. Can anyone shed any light on it for me?

Thanks for any help.

Baz<

Answer 1

From Android 6+

Beginning in Android 6.0 (API level 23), users grant permissions to apps while the app is running, not when they install the app...

And you need to add something like:

  if (ContextCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) 
  {
        ActivityCompat.requestPermissions(
                this,
                new String[] { Manifest.permission.WRITE_EXTERNAL_STORAGE },
                PERMISSION_REQUEST_WRITE_EXTERNAL_STORAGE);
  }

https://developer.android.com/training/permissions/requesting.html