LayerDrawable.java 文件源码

/**
 * Populates <code>outline</code> with the first available (non-empty) layer outline.
 *
 * @param outline Outline in which to place the first available layer outline
 */
@Override
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
public void getOutline(@NonNull Outline outline) {
    final ChildDrawable[] array = mLayerState.mChildren;
    final int N = mLayerState.mNum;
    for (int i = 0; i < N; i++) {
        final Drawable dr = array[i].mDrawable;
        if (dr != null) {
            dr.getOutline(outline);
            if (!outline.isEmpty()) {
                return;
            }
        }
    }
}