android.os.FileUriExposedException Error - XAMARIN - xamarin

Question

I'm trying to do the file picker thing, and it works with lower SDK versions but in this case (android 7.1) it requires the FileProvider.
The thing is that I have seen a lot of answers on the internet and I think that's all OK with my code. What do you think? Why can't I find the reference to the FileProvider in my class?
Hope someone has the idea why this is not working for me, here is the code:
AndroidManifest.xml:
<?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.companyname.AppQ4evo" android:installLocation="preferExternal">
<uses-sdk android:minSdkVersion="16" android:targetSdkVersion="27" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS" />
<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CONTROL_LOCATION_UPDATES" />
<uses-permission android:name="android.permission.LOCATION_HARDWARE" />
<uses-permission android:name="android.permission.INSTALL_LOCATION_PROVIDER" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application android:label="AppQ4evo.Android" android:icon="#drawable/srw_circular">
<provider
android:name="android.support.v4.content.FileProvider"
android:authorities="${applicationId}.com.companyname.AppQ4evo.fileprovider"
android:grantUriPermissions="true"
android:exported="false">
<meta-data
android:name="android.support.FILE_PROVIDER_PATHS"
android:resource="#xml/filepaths" />
</provider>
</application>
</manifest>
Resources/xml/filepaths.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>
EDIT1(The Error):

Answer 1

So this was not easy to find out, but it look's like I need to add-in this extention:
https://marketplace.visualstudio.com/items?itemName=EgorBogatov.XamarinGradleBindings#qna
By add-in this you can now add references to the android directly like, and-in references from java(In my case FileProvider).
The tutorial for this is right in this link at github:
https://github.com/EgorBo/Xamarin.GradleBindings
Hope it helps people with this problem.