QMUICollapsingTopBarLayout.java 文件源码

/**
 * Set the drawable to use for the status bar scrim from resources.
 * Providing null will disable the scrim functionality.
 * <p>
 * <p>This scrim is only shown when we have been given a top system inset.</p>
 *
 * @param drawable the drawable to display
 * @see #getStatusBarScrim()
 */
public void setStatusBarScrim(@Nullable Drawable drawable) {
    if (mStatusBarScrim != drawable) {
        if (mStatusBarScrim != null) {
            mStatusBarScrim.setCallback(null);
        }
        mStatusBarScrim = drawable != null ? drawable.mutate() : null;
        if (mStatusBarScrim != null) {
            if (mStatusBarScrim.isStateful()) {
                mStatusBarScrim.setState(getDrawableState());
            }
            DrawableCompat.setLayoutDirection(mStatusBarScrim,
                    ViewCompat.getLayoutDirection(this));
            mStatusBarScrim.setVisible(getVisibility() == VISIBLE, false);
            mStatusBarScrim.setCallback(this);
            mStatusBarScrim.setAlpha(mScrimAlpha);
        }
        ViewCompat.postInvalidateOnAnimation(this);
    }
}