Android Build a Simple Android App with Java Testing and Debugging Toast Notifications

I tried all the steps. But there is an error. It says 'Cannot Resolve Symbol R'

In file, we use command findViewById( Here, it says Cannot Resolve symbol 'R'. Error: failed linking file resources

1 Answer

Seth Kroger
Seth Kroger
Treehouse Moderator 56,217 Points

R is a class file automatically generated by Android Studio for your project. If you have an error related to it your first step should be to do a Clean then Rebuild project from the Build menu. This will usually fix the issue but keep an eye out for error messages that will point out the problem (With R, usually a mistake in an XML file).