The solution to this problem depends on the version of the Android support library you’re using: Support library 26.0.0-beta2 This android support library version has a bug causing the mentioned problem In your Gradle build file use: with: and everything should work fine now. Library version 28 (beta) These new versions seem to suffer from … Read more
I think you’re developing for Android Lollipop, but anyway include this line: to your theme declaration inside of your app/src/main/res/values/styles.xml. Also, if you’re using AppCompatActivity support library of version 22.1 or greater, add this line: Your theme declaration may look like this after all these additions:
By setting activity theme in Manifest,
What the warning is telling you is that actionBarColor shouldn’t be a global variable (i.e. a field), because it’s only used in one method (onCreate). This is good advice: you should always minimize the scope of your variables, because it improves readability and reduces possibilities for programming errors. To get rid of the warning, fix the problem … Read more