TintLayerDrawable.java 文件源码

/**
 * Updates tint of a layer with the specified <var>layerId</var> of the wrapped drawable
 * depends on the specified <var>stateSet</var>.
 *
 * @param layerId  Id of the desired layer of which tint to update.
 * @param stateSet State set to properly resolve tint color.
 * @return {@code True} if tint has ben updated, {@code false} otherwise.
 */
private boolean updateDrawableLayerTint(int layerId, int[] stateSet) {
    if ((mPrivateFlags & PFLAG_HAS_COLOR_FILTER) == 0) {
        final Drawable drawable = ((LayerDrawable) mDrawable).findDrawableByLayerId(layerId);
        if (drawable == null) {
            return false;
        }

        final DrawableLayerTint layerTint = mDrawableLayerTints != null ? mDrawableLayerTints.get(layerId) : null;
        if (layerTint != null && layerTint.tintList != null && layerTint.tintMode != null) {
            final int tintColor = layerTint.tintList.getColorForState(stateSet, layerTint.currentTint);

            if (tintColor != layerTint.currentTint || (mPrivateFlags & PFLAG_TINT_COLOR_CACHING_ENABLED) == 0) {
                drawable.setColorFilter(new PorterDuffColorFilter(tintColor, layerTint.tintMode));
                layerTint.currentTint = tintColor;
            }
        } else {
            drawable.clearColorFilter();
        }
        return true;
    }
    return false;
}