如何在Xamarin形式的对象图像上方设置标签对象

Question

I tried several solutions, but still remains below, the tests that I have done are: first solution

<RelativeLayout x:Name="locationLayout" Grid.Row="0" Grid.Column="0" VerticalOptions="End" HorizontalOptions="End">
   <Image x:Name="locationIcon"/>
   <Label Text="Posizione" x:Name="posizioneLabel" TextColor="#fff" HorizontalTextAlignment="Center" FontSize="Medium"></Label>
</RelativeLayout>

I would like that the label was above image, I have to make a hover effect.

you can find a solution that dynamically over the image remains the label object in the bottom?

Answer 1

You could try putting the objects in the same Grid

<Grid>
   <Image x:Name="locationIcon"/>
   <Label Text="Posizione" x:Name="posizioneLabel" TextColor="#fff" HorizontalTextAlignment="Center" FontSize="Medium"></Label>
</Grid>

This will render the Image at the back and the text ontop centered horizontally at the top

Answer 2

Answer

The best way to accomplish this is to create the view in the C# code-behind, because, in the code-behind, we can take advantage of using Func s to dynamically resize our UI and align the UI relative to other elements.

This Stack Overflow post has more information about how to center UI Elements in Xamarin.Forms:

Xamarin.Forms: How to center views using Relative Layout? `Width` and `Height` return -1

Sample Code

using System;

using Xamarin.Forms;

namespace SampleApp
{
    public class App : Application
    {
        public App()
        {
            var floatingLabel = new Label
            {
                Text = "This Label Is Centered"
            };

            var circleImage = new Image
            {
                Source = "circle"
            };

            var relativeLayout = new RelativeLayout();

            Func<RelativeLayout, double> getfloatingLabelHeight = (p) => floatingLabel.Measure(p.Width, p.Height).Request.Height;
            Func<RelativeLayout, double> getfloatingLabelWidth = (p) => floatingLabel.Measure(p.Width, p.Height).Request.Width;

            Func<RelativeLayout, double> getCircleImageHeight = (p) => circleImage.Measure(p.Width, p.Height).Request.Height;
            Func<RelativeLayout, double> getCircleImageWidth = (p) => circleImage.Measure(p.Width, p.Height).Request.Width;

            relativeLayout.Children.Add(circleImage,
                Constraint.RelativeToParent(parent => parent.Width / 2 - getCircleImageWidth(parent) / 2),
                Constraint.RelativeToParent(parent => parent.Height / 2 - getCircleImageHeight(parent) / 2)
            );
            relativeLayout.Children.Add(floatingLabel,
                Constraint.RelativeToView(circleImage, (parent, view) => view.X + getCircleImageWidth(parent) / 2 - getfloatingLabelWidth(parent) / 2),
                Constraint.RelativeToView(circleImage, (parent, view) => view.Y + getCircleImageHeight(parent) / 2 - getfloatingLabelHeight(parent) / 2)
            );

            MainPage = new ContentPage { Content = relativeLayout };
        }
    }
}