[compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity] [compatactivity]

Solution:

You can also find the shortcut key of “Project Structure”, then find app–Dependencies, and click “+” in the upper right corner, as shown in the picture below

Click on the “Library dependency”

Then search box, enter the com. Android. Support: appcompat – v7 added on.