using Xamarin.Forms;

namespace RelativeLayoutExample
{
    public class MyContentPage : ContentPage
    {
        public MyContentPage()
        {
            RelativeLayout relativeLayout = new RelativeLayout();

            Label upperLeft = new Label
            {
                Text = "Upper Left",
                FontSize = 20
            };

            relativeLayout.Children.Add(
                upperLeft,
                Constraint.Constant(0),
                Constraint.Constant(0));

            Label constantLabel = new Label
            {
                Text = "Constants are Absolute",
                FontSize = 20
            };

            relativeLayout.Children.Add(
                constantLabel,
                Constraint.Constant(100),
                Constraint.Constant(100),
                Constraint.Constant(50),
                Constraint.Constant(200));

            Label halfwayDown = new Label
            {
                Text = "Halfway down and across",
                FontSize = 15
            };

            relativeLayout.Children.Add(
                halfwayDown,
                Constraint.RelativeToParent(
                    (Parent) =>
                    {
                        return Parent.Width / 2;
                    }),
                Constraint.RelativeToParent(
                    (Parent) =>
                    {
                        return Parent.Height / 2;
                    })
                );

            BoxView boxView = new BoxView
            {
                Color = Color.Accent,
                WidthRequest = 150,
                HeightRequest = 150,
                HorizontalOptions = LayoutOptions.Center,
                VerticalOptions = LayoutOptions.CenterAndExpand
            };

            relativeLayout.Children.Add(
                boxView,
                Constraint.Constant(0),             // X
                Constraint.RelativeToParent(        // Y
                    (Parent) =>
                    {
                        return Parent.Height / 2;
                    }
                ),
                Constraint.RelativeToParent(        // width
                    (Parent) =>
                    {
                        return Parent.Width / 2;
                    }),
                Constraint.RelativeToParent(        // height
                    (Parent) =>
                    {
                        return Parent.Height / 2;
                    })
                );

            Content = relativeLayout;
        }
    }
}