Cannot resolve symbol 'NonNull' after Android Studio update

Question

I recently updated Android Studio. Afterwards it seems to no longer being able to resolve some support annotations, such as @NonNull or @Nullable. It did work just fine before updating. However, everything is still compiling and I am able to execute Code, but still it shows the symbol cannot be resolved message at my imports.

What I have already tried so far:

1. Included the dependency in build.gradle (Module: Application):

   compile 'com.android.support:support-annotations:27.0.0' 

2. I have invalidated Caches and restarted
3. Cleaning and rebuilding the project
4. (Edit) Synched Gradle

I have no idea why this is not working and would really appreciate your help.

Answer 1

As of android api 29 ('targetSdkVersion' 29) com.android.support has been moved to 'androidx' library.

In your build.gradle file(app level), dependencies block use...

dependencies{      ...     implementation 'androidx.annotation:annotation:1.1.0'  } 

And in your .java files use import as follows:

import androidx.annotation.NonNull; 

Again build your project!