viewModels()爆红，修复，添加双向绑定，

添加依赖

implementation 'androidx.lifecycle:lifecycle-viewmodel-ktx:2.3.1'
implementation 'androidx.lifecycle:lifecycle-livedata-ktx:2.3.1'

implementation "androidx.activity:activity-ktx:1.2.0"
implementation "androidx.fragment:fragment-ktx:1.3.0"

其他依赖,google官方文档下载

dependencies {
    def lifecycle_version = "2.3.1"
    def arch_version = "2.1.0"

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

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

    // Jetpack Compose Integration for ViewModel
    implementation "androidx.lifecycle:lifecycle-viewmodel-compose:1.0.0-alpha04"

    // Annotation processor
    kapt "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-ktx:$lifecycle_version"

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

添加双向绑定

buildFeatures {
    viewBinding true
}