Put the following lines of code:
RectF drawableRect = new RectF(0, 0, image_width, image_height); RectF viewRect = new RectF(0, 0, screen_width, screen_height); matrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER);
Hope this will help you.

Ok, I've corrected the error, just had to put the following lines of code:
RectF drawableRect = new RectF(0, 0, image_width, image_height); RectF viewRect = new RectF(0, 0, screen_width, screen_height); matrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER);
Hopefully someone help, thank you very much for answering.