RoundedDrawable.java 文件源码

public static Drawable fromDrawable(Drawable drawable) {
  if (drawable != null) {
    if (drawable instanceof RoundedDrawable) {
      // just return if it's already a RoundedDrawable
      return drawable;
    } else if (drawable instanceof LayerDrawable) {
      LayerDrawable ld = (LayerDrawable) drawable;
      int num = ld.getNumberOfLayers();

      // loop through layers to and change to RoundedDrawables if possible
      for (int i = 0; i < num; i++) {
        Drawable d = ld.getDrawable(i);
        ld.setDrawableByLayerId(ld.getId(i), fromDrawable(d));
      }
      return ld;
    }

    // try to get a bitmap from the drawable and
    Bitmap bm = drawableToBitmap(drawable);
    if (bm != null) {
      return new RoundedDrawable(bm);
    }
  }
  return drawable;
}