CoordinatorLayout
CoordinatorLayout相当于一个功能更加强大的FrameLayout，主要有两个用途：
- 作为顶层布局；
- 作为协调与子布局之间交互的容器。
通过为子布局指定Behaviors，可以为子布局之间提供不同的交互。CoordinatorLayout的子布局可以通过实现CoordinatorLayout.AttachedBehavior接口为自身添加默认行为（behavior）。简单来说，CoordinatorLayout相当于一个第三方，通过Behaviors属性对子布局之间进行行为交互控制。具体如何控制如下：
##CoordinatorLayout
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {...for (int i = 0; i < childCount; i++) {final View child = mDependencySortedChildren.get(i);if (child.getVisibility() == GONE) {// If the child is GONE, skip...continue;}final LayoutParams lp = (LayoutParams) child.getLayoutParams();...final Behavior b = lp.getBehavior();if (b == null || !b.onMeasureChild(this, child, childWidthMeasureSpec, keylineWidthUsed,childHeightMeasureSpec, 0)) {onMeasureChild(child, childWidthMeasureSpec, keylineWidthUsed,childHeightMeasureSpec, 0);}...}...
}##CoordinatorLayout.Behavior<V extends android.view.View>
/*** @return true if the Behavior measured the child view, false if the CoordinatorLayout should perform its default measurement*/
public boolean onMeasureChild(CoordinatorLayout parent, V child, int parentWidthMeasureSpec, int widthUsed,int parentHei