无法在 ViewModelProviders 中解析 android.support.v4.app.FragmentActivity 的方法

Question

我正在尝试在我的应用程序中实现架构组件，但是当我要将 lifecycleowner 添加到我的片段内的视图模型时，getActivity() 其显示消息

Cannot resolve method of android.support.v4.app.FragmentActivity

这是我的代码：

 viewModel = ViewModelProviders.of(getActivity()).get(MyViewModel.class);
        viewModel.setToken(token);
        viewModel.getRecent().observe(getActivity(), new Observer<List<Recent>>() {
            @Override
            public void onChanged(List<Recent> recent) {
                adapter.setData(recent);
            }
        });

我的片段来源于android.support.v4.app.Fragment

并且 MyActivity 是扩展 AppCompatActivity

这是我的 Gradle 文件：

    def paging_version = "2.1.0"
    def lifecycle_version = "2.0.0"
    def room_version = "2.1.0-alpha04"

    implementation "androidx.room:room-runtime:$room_version"
    annotationProcessor "androidx.room:room-compiler:$room_version"
    implementation "androidx.paging:paging-runtime:$paging_version"
    implementation "androidx.lifecycle:lifecycle-extensions:$lifecycle_version"
    implementation "androidx.lifecycle:lifecycle-common-java8:$lifecycle_version"

如何解决这个问题？提前致谢。

Answer 1

问题

在androidx.lifecycle.ViewModelProviders.of(FragmentActivity)中，他们接受androidx.fragment.app.FragmentActivity，而不是android.support.v4.app.FragmentActivity。

解决方案

使用从 Android Studio 3.2 引入的 Migrate to AndroidX 将整个项目迁移到 AndroidX。您可以在 this page
更改依赖项版本以支持库版本。可以找到依赖版本 this page

dependencies {
    def lifecycle_version = "1.1.1"

    // ViewModel and LiveData
    implementation "android.arch.lifecycle:extensions:$lifecycle_version"
    // alternatively - just ViewModel
    implementation "android.arch.lifecycle:viewmodel:$lifecycle_version" // For Kotlin use viewmodel-ktx
    // alternatively - just LiveData
    implementation "android.arch.lifecycle:livedata:$lifecycle_version"
    // alternatively - Lifecycles only (no ViewModel or LiveData).
    //     Support library depends on this lightweight import
    implementation "android.arch.lifecycle:runtime:$lifecycle_version"

    annotationProcessor "android.arch.lifecycle:compiler:$lifecycle_version" // For Kotlin use kapt instead of annotationProcessor
    // alternately - if using Java8, use the following instead of compiler
    implementation "android.arch.lifecycle:common-java8:$lifecycle_version"

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

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

无法在 ViewModelProviders 中解析 android.support.v4.app.FragmentActivity 的方法

Cannot resolve method of android.support.v4.app.FragmentActivity in ViewModelProviders

java

android

mvvm

android-architecture-components