Unresolved reference: Observable in Android Studio

Question

Updated to Android Studio 3.4, with Gradle 5.1.1 and Kotlin 1.3.10 as minimum versions. Cannot run project anymore due to reactivex.Observable not being found. Has anyone found a solution?

Was using rxBinding lib, also tried using latest vesions RxJava 2.2.8 and RxAndroid 2.1.1 with no success.

Answer 1

Along with the dependency of RxKotlin use this

api 'io.reactivex.rxjava2:rxjava:2.2.0'

Only works for Gradle 5.0 or above

Answer 2

Downgrading the build.gradle(project) from classpath 'com.android.tools.build:gradle:3.4.0' to classpath 'com.android.tools.build:gradle:3.2.1' might be help you

Answer 3

The accepted answer ended up leading me to the solution: leaving the gradle-wrapper.properties intact and don't increase the gradle version at all. We'll see if a future lib update will solve it for gradle 3.4.

Answer 4

The issue is that you need to use RxJava 2.2.8 and if you check the RxAndroid gradle file they are using the RxJava version 2.2.6 :

https://github.com/ReactiveX/RxAndroid/blob/2.x/rxandroid/build.gradle

If you force RxJava to use version 2.2.8 it will work.

Add to gradle:

implementation 'io.reactivex.rxjava2:rxjava:2.2.8

Answer 5

Yeah the workaround* for me was to downgrade from gradle 5.1.1 to 4.10.1 and also to the latest android gradle plugin prior to 3.4.0, which is 3.3.2.

I did this in gradle/wrapper/gradle-wrapper.properties by changing to the following: distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.1-all.zip

I then also changed the following in my root build.gradle file:

'com.android.tools.build:gradle:3.4.0' to 'com.android.tools.build:gradle:3.3.2'