Failed to resolve variable '${animal.sniffer.version}' when migrate to AndroidX

Solution 1:

I fix this with two steps

1) File -> Invalidate Caches / restart...

2) Build -> Clean project

Solution 2:

I got the same error after updating my build.gradle file with AndroidX Test dependencies. Turns out I forgot to remove the old junit dependency. So for me, the fix was simply to remove the following dependency:

dependencies {
    ...
    testImplementation 'junit:junit:4.12'
}

Solution 3:

Adding Java 8 support to build.gradle file fixed issue for me

android {
     ...

     //Add the following configuration in order to target Java 8.
     compileOptions {
         sourceCompatibility JavaVersion.VERSION_1_8
         targetCompatibility JavaVersion.VERSION_1_8
     }
}