SeekBarCompat.java 文件源码

/***
 * Method called from APIs below 21 to setup Progress Color
 */
private void setupProgressColor() {
    try {
        //load up the drawable and apply color
        LayerDrawable ld = (LayerDrawable) getProgressDrawable();
        ScaleDrawable shape = (ScaleDrawable) (ld.findDrawableByLayerId(android.R.id.progress));
        shape.setColorFilter(mProgressColor, PorterDuff.Mode.SRC_IN);

        //set the background to transparent
        NinePatchDrawable ninePatchDrawable = (NinePatchDrawable) (ld.findDrawableByLayerId(android.R.id.background));
        ninePatchDrawable.setColorFilter(Color.TRANSPARENT, PorterDuff.Mode.SRC_IN);
    } catch (NullPointerException e) {
        //TODO: Handle exception
    }
}