Btukfyl

I am able to set image in Non-Custom ImageView but unable to set Image in Custom ImageView, app loads successfully but unable to see the Image, below is the code.

public class MainActivity : AppCompatActivity

{





    public ImageTestView imageView;



    protected override void OnCreate(Bundle savedInstanceState)

    {

        base.OnCreate(savedInstanceState);



        SetContentView(Resource.Layout.activity_main);

        imageView = FindViewById<ImageTestView>(Resource.Id.imageView1);

        imageView.SetImageResource(Resource.Mipmap.line_indent);



    }

}



<RelativeLayout 

     xmlns:android="http://schemas.android.com/apk/res/android"

     xmlns:app="http://schemas.android.com/apk/res-auto"

     xmlns:tools="http://schemas.android.com/tools"

     android:layout_width="match_parent"

     android:layout_height="match_parent">

   <ImageViewTestProject.ImageTestView

         android:layout_width="match_parent"

         android:layout_height="match_parent"

         android:id="@+id/imageView1" />





</RelativeLayout>



public class ImageTestView : ImageView

{

    public ImageTestView(Context context,IAttributeSet attr) :

        base(context,attr)

    {



    }

}

Update

In the end, adding the image background through XML ended up solving the issue.

android:background="@mipmap/imagename"

Well I think the reason it's not working is that of the unavailable constructors and improper initialization

  public class ImageTestView : ImageView

  {

    Context mContext;

    public ImageTestView (Context context) : base(context)

    {

        init(context, null);

    }



    public ImageTestView (Context context, Android.Util.IAttributeSet attrs) : base(context, attrs)

    {

        init(context, attrs);

    }



    public ImageTestView (Context context, Android.Util.IAttributeSet attrs, int defStyleAttr) : base(context, attrs, defStyleAttr)

    {

        init(context, attrs);

    }



    public ImageTestView (Context context, Android.Util.IAttributeSet attrs, int defStyleAttr, int defStyleRes) : base(context, attrs, defStyleAttr, defStyleRes)

    {

        init(context, attrs);

    }



    private void init(Context ctx, Android.Util.IAttributeSet attrs)

    {

        mContext = ctx;

    }

  }

Then use this custom imageview in your app like:

<RelativeLayout 

 xmlns:android="http://schemas.android.com/apk/res/android"

 xmlns:app="http://schemas.android.com/apk/res-auto"

 xmlns:tools="http://schemas.android.com/tools"

 android:layout_width="match_parent"

 android:layout_height="match_parent">



 <ImageViewTestProject.ImageTestView

     android:layout_width="match_parent"

     android:layout_height="match_parent"

     android:id="@+id/imageView1" />

 </RelativeLayout>

And then you can set the image resource to it like this:

    var imageView = FindViewById<ImageTestView>(Resource.Id.imageView1);

    imageView?.SetImageResource(Resource.Mipmap.line_indent);

Revert in case this does not work or in case of queries

1.First thing you not doing anything in custom ImageTestView class.

2.And setting the image Resource is wrong.either you have to taking from Drawable folder it should be.

imageView.SetImageResource(Resource.Drawable.line_indent);

I don't know in Xamarin Android.But if you know Android please refer this Example.it's bit similar to xamarin Android

http://www.java2s.com/Code/Android/UI/extendsImageView.htm