Widget - ImageView Zoomable

//ZoomIn
float x=preview.getScaleX(), y=preview.getScaleY(),yenix=x+1,yeniy=y+1;
preview.setScaleX(yenix);
preview.setScaleY(yeniy);

//ZoomOut
float x=preview.getScaleX(), y=preview.getScaleY(),yenix=x-1,yeniy=y-1;
preview.setScaleX(yenix);
preview.setScaleY(yeniy);