You will get ‘Unresolved reference…” error when you don’t call invalidateAll method on a binding object.

Make sure you use it like this:

Create a binding field:

 private lateinit var binding: ActivityMainBinding
 

Assign binding object in onCreate:

binding = DataBindingUtil.setContentView(this, R.layout.activity_main)

Call invalidateAll() on a binding object:

binding.invalidateAll()

I am learning to use data binding in Android Kotlin development and I have linked my data class with my binding object with no compilation errors. However, in order to refresh my binding object to reflect changes to the data object I need to call invalidateAll(). I am getting ‘Unresolved reference: invalidateAll’ and I can’t figure out why.

Here is my build.gradle(:app):

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'
apply plugin: 'kotlin-kapt'

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.0"

    defaultConfig {
        applicationId "com.example.aboutme"
        minSdkVersion 19
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }

    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
    dataBinding {
        enabled = true
    }
}

dependencies {
    implementation fileTree(dir: "libs", include: ["*.jar"])
    implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
    implementation 'androidx.core:core-ktx:1.3.0'
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test.ext:junit:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    kapt "com.android.databinding:compiler:3.0.0-beta1"
}

I have also imported DataBindingUtil and ViewDataBinding (which registers as unused even though invalidateAll should be a method of ViewDataBinding?)

import androidx.databinding.ViewDataBinding