How to create IAttributeSet from XML string using XmlReader in .NET Android?

Question

I am trying to use an ExoPlayer constructor in Android .NET which requires an IAttributeSet to set some parameters as per this question.

I am trying to solve the creation of the IAttributeSet, but cannot seem to succeed.

In Visual Studio 2022, if one goes:

1. File > New > Android Application
2. Add the ExoPlayer NuGet Xam.Plugins.Android.ExoPlayer
3. Then in MainActivity.cs, one can try the following code:

protected override void OnCreate(Bundle? savedInstanceState) {
    base.OnCreate(savedInstanceState);
    
    string xmlString =
        "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" +
        "<Com.Google.Android.Exoplayer2.UI.PlayerView " +           
        "android:id=\"@+id/player_view\" " +
        "app:surface_type=\"texture_view\" " + //KEY NEEDED LINE FOR GOAL
        "android:layout_width=\"match_parent\" " +
        "android:layout_height=\"match_parent\"/>";
    
    XmlReader xmlReader = XmlReader.Create(new StringReader(xmlString));
    System.Diagnostics.Debug.WriteLine("XML READER " + xmlReader.AttributeCount);
            
    Android.Util.IAttributeSet attributes = Android.Util.Xml.AsAttributeSet(xmlReader);
    System.Diagnostics.Debug.WriteLine("ATTRIBUTES " + attributes.AttributeCount);
    
    Com.Google.Android.Exoplayer2.UI.StyledPlayerView styledPlayerView = new(this, attributes);            

No errors are given in Visual Studio on coding. However two problems are evident on running it:

1. xmlReader.AttributeCount & attributes.AttributeCount both return as 0 which I presume means they are not getting any XML set into them correctly.
2. The ExoPlayer constructor line returns the error **Java.Lang.ClassCastException:** 'android.util.XmlPullAttributes cannot be cast to android.content.res.XmlBlock$Parser'

Why is this code is failing on these two points? The only other place I see the error from (2) is here and I am not sure of how this works.

How can I create the IAttributeSet that is required for the ExoPlayer constructor?

Thanks for any help.

Answer 1

After further research there is no way to do this in .NET except:

1. Create XML file named "test.xml" in Resources\layout
2. Copy paste into it:

<?xml version="1.0" encoding="utf-8" ?> 
<com.google.android.exoplayer2.ui.StyledPlayerView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/test"
    app:surface_type="texture_view"
    android:layout_width= "match_parent"
    android:layout_height= "match_parent" />

3. Run code in MainActivity.cs:

XmlReader xmlResource = this.Resources.GetXml(Resource.Layout.test);
xmlResource.Read();
Android.Util.IAttributeSet attributes = Android.Util.Xml.AsAttributeSet(xmlResource);
Com.Google.Android.Exoplayer2.UI.StyledPlayerView styledPlayerView = new(this, attributes); 

This does work. But there is no way to programmatically create the xml. It must be pre-stored in Resources and loaded from there.