android lifecycle implementation code example

Example 1: android viewmodel dependency

dependencies {
    def lifecycle_version = "2.2.0"
    def arch_version = "2.1.0"

    // ViewModel
    implementation "androidx.lifecycle:lifecycle-viewmodel:$lifecycle_version"
    // LiveData
    implementation "androidx.lifecycle:lifecycle-livedata:$lifecycle_version"
    // Lifecycles only (without ViewModel or LiveData)
    implementation "androidx.lifecycle:lifecycle-runtime:$lifecycle_version"

    // Saved state module for ViewModel
    implementation "androidx.lifecycle:lifecycle-viewmodel-savedstate:$lifecycle_version"

    // Annotation processor
    annotationProcessor "androidx.lifecycle:lifecycle-compiler:$lifecycle_version"
    // alternately - if using Java8, use the following instead of lifecycle-compiler
    implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"

    // optional - helpers for implementing LifecycleOwner in a Service
    implementation "androidx.lifecycle:lifecycle-service:$lifecycle_version"

    // optional - ProcessLifecycleOwner provides a lifecycle for the whole application process
    implementation "androidx.lifecycle:lifecycle-process:$lifecycle_version"

    // optional - ReactiveStreams support for LiveData
    implementation "androidx.lifecycle:lifecycle-reactivestreams:$lifecycle_version"

    // optional - Test helpers for LiveData
    testImplementation "androidx.arch.core:core-testing:$arch_version"
}

Example 2: lifecycle android

onCreate	called when activity is first created.
onStart	called when activity is becoming visible to the user.
onResume	called when activity will start interacting with the user.
onPause	called when activity is not visible to the user.
onStop	called when activity is no longer visible to the user.
onRestart	called after your activity is stopped, prior to start.
onDestroy	called before the activity is destroyed.