XML中NavHostFragment无法访问的运行时报错问题排查

我在尝试接入新的Navigation库时，严格按照官方指南操作，结果运行App时遇到了以下报错：

Caused by: android.view.InflateException: Binary XML file line #11: Binary XML file line #11: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #11: Error inflating class fragment
Caused by: android.app.Fragment$InstantiationException: Unable to instantiate fragment androidx.navigation.fragment.NavHostFragment: make sure class name exists, is public, and has an empty constructor that is public

这个报错指向我的activity_home.xml文件，文件内容如下：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".ui.home.HomeActivity">

    <fragment
        android:id="@+id/fragment_navigation_host"
        android:name="androidx.navigation.fragment.NavHostFragment"
        app:defaultNavHost="true"
        app:navGraph="@navigation/navigation_home" />

</FrameLayout>

排查过程中，我发现NavHostFragment源码依赖的是android.support.v4.app.Fragment，但我的整个项目都在使用androidx.fragment.app.Fragment，这让我怀疑是兼容性问题。我的依赖配置如下：

// AndroidX
implementation "androidx.appcompat:appcompat:$appCompatVersion"
implementation "androidx.constraintlayout:constraintlayout:$constraintLayoutVersion"
implementation "androidx.lifecycle:lifecycle-extensions:$lifecycleVersion"
implementation "androidx.recyclerview:recyclerview:$recyclerViewVersion"
implementation "androidx.room:room-runtime:$roomVersion"
implementation "androidx.room:room-rxjava2:$roomVersion"
kapt "androidx.room:room-compiler:$roomVersion"

// Navigation
implementation "android.arch.navigation:navigation-fragment-ktx:$navigationVersion"
implementation "android.arch.navigation:navigation-ui-ktx:$navigationVersion"

可以看到，除了Navigation库，其他依赖都是AndroidX版本——我之前以为Navigation库还没完成AndroidX迁移，后来找到了androidx.navigation的依赖，但Gradle一直无法下载对应的包。另外，我的gradle.properties已经启用了Jetifier工具：

android.enableJetifier=true
android.useAndroidX=true

问题解决更新 #

这个兼容性问题已经在Android Studio 3.2 Canary 17版本中得到修复。解决步骤如下：

1. 升级Android Studio到3.2 Canary 17或更高版本
2. 将Navigation库的依赖替换为AndroidX版本：

   implementation "androidx.navigation:navigation-fragment-ktx:$navigationVersion"
   implementation "androidx.navigation:navigation-ui-ktx:$navigationVersion"
   

3. 清除Android Studio缓存并重启IDE，这样可以消除残留的代码警告

内容的提问来源于stack exchange，提问作者Nominalista