Android Unused Import Statements

That is, we imported a module, but there is no meaning to use it. This is pep8 Programming specification check. There are several solutions:  
1. Click the invalidate caches/restart option under file, click it, this is to clear the studio cache. 2. Compile, click the sync project button you can also try to click build>clean project/rebuild project If it still doesn’t work, it’s a code problem. I’m a rookie. I spent a lot of time searching for the reason. I finally found it. It turned out that I accidentally created the fragment. Lowercase the file name, the most basic mistake, alas, it seems that you need to be careful, careful, and more careful in writing code in the future...