FileProvider抛出异常的GetUriForFile | FileProvider抛出异常的GetUriForFile

本文介绍了FileProvider抛出异常的GetUriForFile的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我也跟着在的，但它不会工作。

I followed the example code on the android developer reference on FileProviders but it won't work.

我已经安装路径文件/出口/ 中的文件提供的定义在我的清单和引用的文件并在该路径存在。

I have setup the path files/exports/ in the file provider definition in my Manifest and the referenced files does exist at that path.

在我的清单：

<provider android:name="android.support.v4.content.FileProvider" android:authorities="com.company.app.fileprovider" android:exported="false" android:grantUriPermissions="true">
    <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths" />
</provider>

而在 XML / file_paths.xml

<?xml version="1.0" encoding="UTF-8" ?>
<paths xmlns:android="http://schemas.android.com/apk/res/android">
    <files-path name="exports" path="exports/"/>
</paths>

然后我试图让内容URI具有以下code：

Then I try to get the content-uri with the following code:

Java.IO.File exportFile =
    new Java.IO.File ("/data/data/com.company.app/files/exports/file.pdf");
Android.Net.Uri exportUri =
    Android.Support.V4.Content.FileProvider.GetUriForFile (this, "com.company.app.fileprovider", exportFile);

不过，我得到这个错误：

However I get this error:

Exception of type 'Java.Lang.NullPointerException' was thrown.
  at Android.Runtime.JNIEnv.CallStaticObjectMethod (IntPtr jclass, IntPtr jmethod, Android.Runtime.JValue[] parms) [0x00064] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.10.2-branch/4b53fbd0/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:1160
  at Android.Support.V4.Content.FileProvider.GetUriForFile (Android.Content.Context context, System.String authority, Java.IO.File file) [0x00000] in <filename unknown>:0
  at com.company.App.ImageAndSubtitle.cloudStorageDidDownloadFile (System.Object sender, com.company.App.CloudStorageEventArgs args) [0x001f7] in /app_path/Screens/ImageAndSubtitle.cs:187
  --- End of managed exception stack trace ---
java.lang.NullPointerException
    at android.support.v4.content.FileProvider.parsePathStrategy(FileProvider.java:243)
    at android.support.v4.content.FileProvider.getPathStrategy(FileProvider.java:217)
    at android.support.v4.content.FileProvider.getUriForFile(FileProvider.java:130)
    at mono.java.lang.RunnableImplementor.n_run(Native Method)
    at mono.java.lang.RunnableImplementor.run(RunnableImplementor.java:29)
    at android.os.Handler.handleCallback(Handler.java:615)
    at android.os.Handler.dispatchMessage(Handler.java:92)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:4838)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:875)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:642)
    at dalvik.system.NativeStart.main(Native Method)

更新

从Android源$ C $ C，我可以追捕下来就我现在知道，在 android.support.v4.content.FileProvider.parsePathStrategy此命令（FileProvider.java:243） 将失败并返回空：

From the Android source code I could hunt that down so far as I now know that this command in android.support.v4.content.FileProvider.parsePathStrategy(FileProvider.java:243) will fail and return null:

final ProviderInfo info = context.getPackageManager().resolveContentProvider(authority, PackageManager.GET_META_DATA);

但我不知道为什么...

But I have no idea why...

推荐答案

我终于找到了如何创建的

I finally found good example code on how to create ContentProviders and FileProviders on https://github.com/commonsguy/cw-omnibus/tree/master/ContentProvider

在我的code实际的错误是，在清单文件我有的应用程序之外提供商标记标记，但一定要进去。
清单必须是这样的：

The actual error in my code was that in the Manifest file I had the provider tag outside of the application tag, but it must be inside.The Manifest must look like this:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" android:versionCode="1" android:versionName="1.0" package="com.company.app">
<uses-sdk android:minSdkVersion="13" />

<permission
    android:name="com.company.app.fileprovider.READ"
    android:description="@string/perm_read"
    android:label="@string/perm_read_label"/>
<uses-permission android:name="com.company.app.fileprovider.READ"/>

<application android:label="MyApp">

    <provider
    android:name="android.support.v4.content.FileProvider"
    android:authorities="com.company.app.fileprovider"
    android:exported="false"
    android:grantUriPermissions="true"
    android:readPermission="com.company.app.fileprovider.READ">
                <meta-data
                android:name="android.support.FILE_PROVIDER_PATHS"
                android:resource="@xml/file_paths" />
    </provider>

</application>
<uses-permission android:name="android.permission.INTERNET" />

</manifest>

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