title: FileProvider throws exception on GetUriForFile
body: <p>I followed the example code on the <a href="http://developer.android.com/reference/android/support/v4/content/FileProvider.html" rel="noreferrer">android developer reference on FileProviders</a> but it won't work.</p>
  
  <p>I have setup the path <code>files/exports/</code> in the file provider definition in my Manifest and the referenced files does exist at that path. </p>
  
  <p>In my Manifest:</p>
  
  <pre><code>&lt;provider android:name="android.support.v4.content.FileProvider" android:authorities="com.company.app.fileprovider" android:exported="false" android:grantUriPermissions="true"&gt;
      &lt;meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths" /&gt;
  &lt;/provider&gt;
  </code></pre>
  
  <p>And in <code>xml/file_paths.xml</code></p>
  
  <pre><code>&lt;?xml version="1.0" encoding="UTF-8" ?&gt;
  &lt;paths xmlns:android="http://schemas.android.com/apk/res/android"&gt;
      &lt;files-path name="exports" path="exports/"/&gt;
  &lt;/paths&gt;
  </code></pre>
  
  <p>Then I try to get the content-uri with the following code:</p>
  
  <pre><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);
  </code></pre>
  
  <p>However I get this error:</p>
  
  <pre><code>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 &lt;filename unknown&gt;: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)
  </code></pre>
  
  <p><strong>Update</strong></p>
  
  <p>From the Android source code I could hunt that down so far as I now know that this command in <code>android.support.v4.content.FileProvider.parsePathStrategy(FileProvider.java:243)</code> will fail and return <code>null</code>:</p>
  
  <pre><code>final ProviderInfo info = context.getPackageManager().resolveContentProvider(authority, PackageManager.GET_META_DATA);
  </code></pre>
  
  <p>But I have no idea why...</p>