AndroidManifest.xml

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

file_paths.xml

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