What is the difference between AppBarLayout vs Toolbar?

问题

I want to include Toolbar in my app, but the design support library just came out with AppBarLayout, so I just need clarification on what the difference is and when I would use one over the other.

回答1:

The AppBarLayout is used to achieve various scrolling behaviors such as collapse, flex space, and quick return.

http://www.google.com/design/spec/patterns/scrolling-techniques.html

http://android-developers.blogspot.com/2015/05/android-design-support-library.html

回答2:

If you want just to include the Toolbar without any scrolling effects you can use Toolbar. But if you want to make some scrolling effects like on the images you need to use AppBarLayout.

More here and here.

回答3:

AppBarLayout is a parent layout of ToolBar and ToolBar is custom ActionBar. if you want scroll action on the ToolBar so you should write ToolBar into the AppBarLayout,before you will write code for scroll the ToolBar, you must know the NestedScrollBar,it is used to scroll the ToolBar. but you cannot connect NestedScrollBar and ToolBar directly,because ToolBar is child of AppBarLayout and NestedScrollBar is sibling of AppBarLayout, that's why your Toolbar should in the AppBarlayout then you can connect AppBarlayout and NestedScrollBarLayout for scrolling action on the toolbar.

来源：https://stackoverflow.com/questions/31328695/what-is-the-difference-between-appbarlayout-vs-toolbar