Android Studio can't find library classes after Gradle build

Question

I\'m trying to add a .jar library to my project into the /libs folder. Here is my grade.build:

    buildscript {
              


        

Answer 1

Goto File ⇒ Invalidate Caches & Restart

Solved my problem

Answer 2

Using the command line, in the root of your project, run :
./gradlew clean && ./gradlew build

Then recompile your project in studio and you should see your new lib.

Answer 3

Set minifyEnabled to false for all your library projects in build.gradle. See accepted answer by Scott Barta in this thread.

See accepted answer by Scott Barta in this thread

Answer 4

• As first option, i think will be enough Syncronizing the Project with Gradle Files.

• Another option, from the command line, run the batch file gradlew.bat located inside your project folder:

./gradlew clean && ./gradlew build

Answer 5

I had a similar situation where Android Studio couldn't find a library that definitely existed. Even though I was able to compile my project in Android Studio, run it from Android Studio in the emulator or on a physical device, and build it from the command line using gradlew, the Android Studio IDE complained Cannot resolve symbol 'ConstraintLayout'. I believe I had imported the library correctly because I followed Google's instructions: https://developer.android.com/training/constraint-layout/#add-constraintlayout-to-your-project.

Anyway, I ended up solving the problem as follows:

1. Close Android Studio
2. Delete the .idea folder in the project's directory
3. Open Android Studio
4. Re-import the project so Android Studio can regenerate the .idea folder

This in-fact solved the problem. I believe Android Studio somehow corrupted the .idea folder when I had done "Android Studio" > "Check for Updates" earlier in the day.