Android Studio 3.1 Cannot Resolve Symbol (Themes, Widget, attr, etc.)

Question

I upgraded Android Studio today to 3.1, and now Android Studio says it cannot resolve symbols for most of the resources (for example ThemeOverlay in style

Answer 1

I updated my gradle version to 4.10.1 and did "fix and reimport". There were no libraries folder under .idea before. And then it worked

Answer 2

How I solved it.:

I updated Android studio to version 3.2, and two steps solved this problem.

1. Deleted from Android studio welcome page.

2. Open project again.

Worked for me.

Answer 3

implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
implementation 'com.android.support:design:26.1.0'

update your dependencies with the above in build.gradle(project)

and put the below code in build.gradle(Module:app)

classpath 'com.android.tools.build:gradle:3.1.1'
classpath 'io.realm:realm-gradle-plugin:3.7.1'
classpath 'com.google.gms:google-services:3.1.0'

Answer 4

Similar error for me when I update to com.android.tools.build:gradle 3.3.1 and gradle-4.10.1

I have tried the following method but didn't work:

1. Clean Project - Rebuild Project
2. Invalidate Caches / Restart
3. Check .xml error (I didn't find any errors about xml )
4. Modify .iml file

I fix this error by modify com.android.tools.build:gradle 3.2.1 and Restart my mac , I didn't know which one can fix it, but it really work for me .