For those working with Kotlin, try changing annotationProcessor
to kapt
in the apps build.gradle
for example:
// Extensions = ViewModel + LiveData
implementation "android.arch.lifecycle:extensions:1.1.0"
kapt "android.arch.lifecycle:compiler:1.1.0"
// Room
implementation "android.arch.persistence.room:runtime:1.0.0"
kapt "android.arch.persistence.room:compiler:1.0.0"
also remember to add this plugin
apply plugin: 'kotlin-kapt'
to the top of the app level build.gradle file and do a clean and rebuild (according to https://codelabs.developers.google.com/codelabs/android-room-with-a-view/#6)
In Android Studio, if you get errors when you paste code or during the build process, select Build >Clean Project. Then select Build > Rebuild Project, and then build again.
UPDATE
If you have migrated to androidx
def room_version = "2.3.0" // check latest version from docs
implementation "androidx.room:room-runtime:$room_version"
kapt "androidx.room:room-compiler:$room_version"
UPDATE 2 (since July 2021)
def room_version = "2.3.0" // check latest version from docs
implementation "androidx.room:room-ktx:$room_version"
kapt "androidx.room:room-compiler:$room_version"