java - 无法解析 ViewModelProviders 中 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，但是当我使用 getActivity() 将生命周期所有者添加到 fragment 内的 View 模型时，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 fragment 源自android.support.v4.app.Fragment

并且 MyActivity 扩展了 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，它们接受androidx.fragment.app.FragmentActivity，而不是android.support.v4.app .FragmentActivity.

解决方案

1. 使用 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中找到信息
2. 更改依赖项版本以支持库版本。可以找到依赖项版本 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"
}