getWidth在缩放后不返回不同的值

Question

I'm trying to find what I'm missing when using setScaleX.

    final ImageView iv = (ImageView) findViewById(R.id.imageView);
    ViewTreeObserver vto = iv.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            // Start at 60
            Log.d("test", "Before"+String.valueOf(iv.getWidth()));
            iv.setScaleX((float) .5);
            // Still at 60 after scale
            Log.d("test", "After"+String.valueOf(iv.getWidth()));
        }

    });

I would of thought the width would have become 30. How do I get the value of the width after scaling?

Answer 1

you can solve it by multiply by scale x or y

 final ImageView iv = (ImageView) findViewById(R.id.imageView);
    ViewTreeObserver vto = iv.getViewTreeObserver();
    vto.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            // Start at 60
            Log.d("test", "Before"+String.valueOf(iv.getWidth()* iv.getScaleX()));
            iv.setScaleX((float) .5);
            // Still at 60 after scale
            Log.d("test", "After"+String.valueOf(iv.getWidth()* iv.getScaleX()));
        }

    });

Answer 2

getWidth() returns the width before transforms are applied to the view ( setScaleX , etc...). So this is expected. This is hinted by the documentation of getDrawingRect :

 These bounds do not account for any transformation properties currently set on the view, 
 such as setScaleX(float) or setRotation(float).