Unresolved reference: Transformations-CodePudding

I'm trying to follow the android documentation to implement Transformations in my project but I run into this problem Unresolved reference: Transformations. I don't know why my project can't see the Transformations class.

I'm using Kotlin version 1.5.21' and here is my code

class MyViewModel(private val repository: PostalCodeRepository) : ViewModel() {
    private val addressInput = MutableLiveData<String>()
    val postalCode: LiveData<String> = Transformations.switchMap(addressInput) {
            address -> repository.getPostCode(address) }


    private fun setInput(address: String) {
        addressInput.value = address
    }
}

Any guidance is really appreciated.

CodePudding user response：

Make sure to import

import androidx.lifecycle.Transformations

If the import gives an Unresolved reference error, add the following dependency to your build.gradle file

dependencies {
    ...
    implementation "androidx.lifecycle:lifecycle-livedata-ktx:2.4.1"
}