Xamarin Android Custom View Not Loading

Question

i am new to Xamarin monoandroid and i am facing a problem in adding a custom view to my layout. i have no idea what i am doing wrong. little help will be great full and this is my custom view class

onDraw method is called but i don't get the output and no errors.

class PositionDrawer : View
    {
        private int count;
        private int position;
        private IPositionDrawer cinterface;
        private Activity cactivity;
        private int container;
        private int p;
        private ScoreFeed scoreFeed1;
        private ScoreFeed scoreFeed2;
        public PositionDrawer(Activity context, int count, int positionr, Activity cactivity) :
            base (context)
        {
            //Initialize ();
            this.cactivity = cactivity;
            this.cinterface = cinterface;
            this.count = count;
            this.position = positionr;
            //this.OnDraw();
            Initialize();
        }

        private void Initialize()
        {
            //this.Invalidate();
           // this.SetMeasuredDimension(100, 100);
            this.SetWillNotDraw(false);
            Console.WriteLine(this.WillNotDraw());
        }
        protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
        {
            base.OnMeasure(widthMeasureSpec, heightMeasureSpec);
        }
        public void SetDrawer(int count, int positionr, Activity cactivity)

        {

           this.cactivity = cactivity;
           this.cinterface = cinterface;
           this.count = count;
           this.position = positionr;

           //base(cactivity);   
        }

         protected override void OnDraw(Canvas canvas)
        {
            base.OnDraw(canvas);
            Paint blue = new Paint();
            blue.Color = Color.Red;

            float screenwidth = cactivity.WindowManager.DefaultDisplay.Width;
            canvas.DrawRect(screenwidth * position-1, 0, screenwidth * position, 20, blue);
            Console.WriteLine("SW1:" + screenwidth + "pos1:" + position);
           // LinearLayout can =cactivity.FindViewById<LinearLayout>(container);
            //cinterface.getview(this);
        }

    }

and i use following code to add view to the layout.

 View pd = new PositionDrawer(this, 3, position, this);
 container = FindViewById<LinearLayout>(Resource.Id.position);
 container.RemoveAllViews();
 container.AddView(pd);

thanks in advance.

Answer 1

You need to implement the correct ctors.

When you implement the View class then you have to at least have the ctor with the following signature:

public PositionDrawer(IntPtr javaReference, JniHandleOwnership transfer)
    : base(javaReference, transfer) { }

And if you are using the View in a AXML layout you also need the one with the following signature:

public PositionDrawer(Context context, IAttributeSet attrs, int defStyle)
    : base(context, attrs, defStyle)

Otherwise when you create Views from code, you need to give them some LayoutParameters otherwise they do not know their own size.