由于找不到 FileProvider 类，因此在模拟器上重新安装后应用程序崩溃 [英] App crashes after reinstall on emulator since FileProvider Class was not found

问题描述

当我在模拟器上运行应用程序时，它总是在第一次尝试时运行.但是当应用程序已经安装在模拟器上时，它通常会在应用程序启动期间导致崩溃.此行为在 Android Studio 2.0 中开始出现.它不会发生在设备上，因此它不是那么重要但只是烦人，因为我总是需要在安装新版本之前从模拟器中删除应用程序.

When I run the app on the emulator it always works on the first try. But when the app is already installed on the emulator it often results in a crash during the start of the app. This behavior started to occur with Android Studio 2.0. It does not occur on devices, therefore it is not so important but only annoying since I always need to delete the app from the emulator before installing a new version.

由于我完全不知道是什么原因导致了这个问题，并且在研究过程中也找不到类似的问题，希望有人能帮助我.

Since I have absolutely no idea what causes this issue and can't find similar issues during research, I hope that somebody can help me.

错误信息:

08-25 09:55:35.023 4214-4214/? E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.mls.Search.Abbott, PID: 4214
    java.lang.RuntimeException: Unable to get provider android.support.v4.content.FileProvider: java.lang.ClassNotFoundException: Didn't find class "android.support.v4.content.FileProvider" on path: DexPathList[[zip file "/data/app/com.mls.Search.Abbott-2/base.apk"],nativeLibraryDirectories=[/data/app/com.mls.Search.Abbott-2/lib/x86, /data/app/com.mls.Search.Abbott-2/base.apk!/lib/x86, /vendor/lib, /system/lib]]
        at android.app.ActivityThread.installProvider(ActivityThread.java:5156)
        at android.app.ActivityThread.installContentProviders(ActivityThread.java:4748)
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4688)
        at android.app.ActivityThread.-wrap1(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1405)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:5417)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
    Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v4.content.FileProvider" on path: DexPathList[[zip file "/data/app/com.mls.Search.Abbott-2/base.apk"],nativeLibraryDirectories=[/data/app/com.mls.Search.Abbott-2/lib/x86, /data/app/com.mls.Search.Abbott-2/base.apk!/lib/x86, /vendor/lib, /system/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
        at android.app.ActivityThread.installProvider(ActivityThread.java:5141)
        at android.app.ActivityThread.installContentProviders(ActivityThread.java:4748) 
        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4688) 
        at android.app.ActivityThread.-wrap1(ActivityThread.java) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1405) 
        at android.os.Handler.dispatchMessage(Handler.java:102) 
        at android.os.Looper.loop(Looper.java:148) 
        at android.app.ActivityThread.main(ActivityThread.java:5417) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
    Suppressed: java.lang.ClassNotFoundException: Didn't find class "android.support.v4.content.FileProvider" on path: DexPathList[[dex file "/data/data/com.mls.Search.Abbott/files/instant-run/dex/slice-slice_3-classes.dex"],nativeLibraryDirectories=[/data/app/com.mls.Search.Abbott-2/lib/x86, /data/app/com.mls.Search.Abbott-2/base.apk!/lib/x86, /vendor/lib, /system/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at com.android.tools.fd.runtime.IncrementalClassLoader$DelegateClassLoader.findClass(IncrementalClassLoader.java:90)
        at com.android.tools.fd.runtime.IncrementalClassLoader.findClass(IncrementalClassLoader.java:62)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
              ... 12 more
            Suppressed: java.lang.ClassNotFoundException: android.support.v4.content.FileProvider
        at java.lang.Class.classForName(Native Method)
        at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
        at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
                ... 13 more
    Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available

清单中的文件提供程序:

File Provider in Manifest:

<provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="${applicationId}.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true">
    <meta-data
        android:name="android.support.FILE_PROVIDER_PATHS"
        android:resource="@xml/filepaths" />
</provider>

推荐答案

如果你正在使用 androidx 库，在 AndroidManifest.xml代码>，更改此:

If you are using androidx libraries, in AndroidManifest.xml, change this:

android:name="android.support.v4.content.FileProvider"

为此:

android:name="androidx.core.content.FileProvider"

这篇关于由于找不到 FileProvider 类，因此在模拟器上重新安装后应用程序崩溃的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！