Android RotateAnimation makes view flicker when trying to rotate view again

Question

I'm trying to implement a floating action button, a simple plus sign which should rotate 45 degrees on selection and rotate back when pressed again. Rotating to 45 degrees works well, but when I press again the image flickers to the original position. How can I prevent the flickering?

public void rotateImageView(final View img, boolean makeRotation) {
    final float rotated = 45.0f;
    final float notRotated = 0.0f;

    final float rotTo;
    final float rotFrom;
    if(makeRotation) {
        rotFrom = rotated;
        rotTo = notRotated;
    }
    else {
        rotFrom = notRotated;
        rotTo = rotated;
    }

    RotateAnimation rotAnim = new RotateAnimation(rotFrom, rotTo,
            Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF,
            0.5f);
    rotAnim.setDuration(200);
    rotAnim.setFillBefore(true);
    rotAnim.setFillAfter(true);

    mAdd.startAnimation(rotAnim);
}