Cannot resolve symbol 'Theme' in styles.xml (Android Studio)

Question

Since today, Android Studio can\'t find the AppCompat themes in styles.xml, but for example AppCompatActivity in code does get recognized. My Android Studio version

Answer 1

This is weird, I encounter this problem as below:

• Android Studio is 3.1.2
• support lib version is 27.0.0

I solve this by below:

1. change support lib version to 27.1.0, and "Sync Project with Gradle Files", then this error disappear
2. change support lib version to 27.0.0，and "Sync Project with Gradle Files", then this error not appear again