How to resolve R.java file loss in Android project

1. The first method, that is, your project has no big problem, then the choice to make, should be able to solve your problem.

2. The second is to see if you have checked the options shown in the diagram, that is, your r.java can be generated automatically.

3. The third deep point is that you clear first, and then build automatically a bit, should be able to.

4. If none of this solves your problem, it's likely that you haven't developed a project in a long time and your SDK is going to be updated.

5. The above four methods can basically solve your problem. If not resolved, you can leave a message.