SeekBarCompat.java 文件源码

/***
 * Method called from APIs below 21 to setup Progress Color
 */
private void setupProgressColor() {
    //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);
}