Didn't find class “androidx.core.content.FileProvider”

问题

I migrated my app to AndroidX and it's crashing on launch on API level 21. My application throws this exception:

10-08 09:42:50.930 11346-11346/com.example.test E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.test, PID: 11346
java.lang.RuntimeException: Unable to get provider androidx.core.content.FileProvider: java.lang.ClassNotFoundException: Didn't find class "androidx.core.content.FileProvider" on path: DexPathList[[zip file "/data/app/com.example.test-1.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.test-1, /vendor/lib, /system/lib]]
    at android.app.ActivityThread.installProvider(ActivityThread.java:5121)
    at android.app.ActivityThread.installContentProviders(ActivityThread.java:4713)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4596)
    at android.app.ActivityThread.access$1600(ActivityThread.java:169)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:146)
    at android.app.ActivityThread.main(ActivityThread.java:5487)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099)
    at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "androidx.core.content.FileProvider" on path: DexPathList[[zip file "/data/app/com.example.test.apk"],nativeLibraryDirectories=[/data/app-lib/com.example.test-1, /vendor/lib, /system/lib]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:67)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:497)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:457)
    at android.app.ActivityThread.installProvider(ActivityThread.java:5106)
    at android.app.ActivityThread.installContentProviders(ActivityThread.java:4713) 
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4596) 
    at android.app.ActivityThread.access$1600(ActivityThread.java:169) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1340) 
    at android.os.Handler.dispatchMessage(Handler.java:102) 
    at android.os.Looper.loop(Looper.java:146) 
    at android.app.ActivityThread.main(ActivityThread.java:5487) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:515) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1283) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1099) 
    at dalvik.system.NativeStart.main(Native Method)

And here is the provider definition in my AndroidManifest.xml file:

<provider
    android:name="androidx.core.content.FileProvider"
    android:authorities="${applicationId}.fileProvider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/provider_paths" />
</provider>

On the latest API level it works fine. Any suggestions would be useful, thanks in advance.

回答1:

It seems that this error came from incomplete configuration of MultiDex in your app. Here you may find the similar issue and here is an article answering it.

I suggest you to check the following (extending App class helped me):

Your Application class (App.class, for instance, if you use it) should extend from MultiDexApplication class:

public class BaseApplication extends MultiDexApplication {}

or if you don't use Application class check your manifest:

<?xml version="1.0" encoding="utf-8"?>
    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
        package="com.example.android.multidex.myapplication">
        <application
            ...
            android:name="android.support.multidex.MultiDexApplication">
            ...
        </application>
    </manifest>

回答2:

The problem is your React Native android project is not in AndroidX while react-native-image-picker is in an AndroidX environment; therefore, it is missing packages from the androidx package library.

Simple fix is adding the following lines to your ./android/gradle.properties file:

android.useAndroidX=true
android.enableJetifier=true

If you have any existing RN libraries that uses old android packages, your project won't build since they will be missing once you updated your project.

A clever tool found here deals with RN libraries that uses old android packages and brings them up to date.

npm i --save-dev jetifier
npx jetify
react-native run-android

All checked out and it's working on my end. Hope this helps anyone and please do share if it does.

Source https://github.com/react-native-community/react-native-image-picker/issues/1088#issuecomment-509755692

回答3:

add below ndk lib support to your project if you have used the external library -

ndk
     {
        abiFilters "armeabi-v7a", "x86", "x86_64", "arm64-v8a"
     }

inside the default config of your app level build.gradle file

defaultConfig 
    {
        applicationId "org.comcast.net"
        minSdkVersion 21
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
        ndk
                {
                    abiFilters "armeabi-v7a", "x86", "x86_64", "arm64-v8a"
                }
    }

it has solved my problem, hopefully it will solve at your end also.

回答4:

The documentation is outdated; use androidx.multidex for androidx:

implementation "androidx.multidex:multidex:2.0.1"

AndroidManifest.xml:

<application
    android:name="androidx.multidex.MultiDexApplication">
</application>

Use the Jetifier when it still uses any com.android.support libraries:

android.enableJetifier=true

来源：https://stackoverflow.com/questions/52696574/didnt-find-class-androidx-core-content-fileprovider