softlion/RxButton.cs

/*
A .NET MAUI button does not have text alignment options so this is a custom button that adds those features.

Open MAUI feature request: https://github.com/dotnet/maui/issues/10463
This implementation is adapted from: https://gist.github.com/softlion/6a11b0ec5acb384743500ffaf92d525e
Other relevant links:
https://github.com/marcoablanco/RxUI.MauiToolkit/blob/develop/RxUI.MauiToolkit/Controls/RxButton.cs
https://github.com/marcoablanco/RxUI.MauiToolkit/blob/develop/RxUI.MauiToolkit/Platforms/Android/Handlers/RxButtonHandler.cs
https://github.com/marcoablanco/RxUI.MauiToolkit/blob/develop/RxUI.MauiToolkit/Platforms/Windows/Handlers/RxButtonHandler.cs
https://github.com/marcoablanco/RxUI.MauiToolkit/blob/develop/RxUI.MauiToolkit/Platforms/iOS/Handlers/RxButtonHandler.cs
*/

using Microsoft.Maui.Handlers;

#if ANDROID
using Google.Android.Material.Button;
#elif IOS
using UIKit;
#elif WINDOWS
using Microsoft.UI.Xaml.Controls;
#endif

namespace Controls;

public static class TextAlignmentButtonExtensions
{
	public static MauiAppBuilder UseTextAlignmentButton(this MauiAppBuilder builder)
	{
		return builder.ConfigureMauiHandlers(
			handlers =>
			{
#if ANDROID
				handlers.AddHandler<TextAlignmentButton, TextAlignmentButtonHandler>();
#elif IOS
				handlers.AddHandler<TextAlignmentButton, TextAlignmentButtonHandler>();
#elif WINDOWS
				handlers.AddHandler<TextAlignmentButton, TextAlignmentButtonHandler>();
#endif
			});
	}
}


/// <summary>
/// Button with text alignment options.
/// </summary>
public class TextAlignmentButton : Microsoft.Maui.Controls.Button
{
    public static readonly BindableProperty HorizontalTextAlignmentProperty = BindableProperty.Create(nameof(HorizontalTextAlignment), typeof(TextAlignment), typeof(TextAlignmentButton));
    public static readonly BindableProperty VerticalTextAlignmentProperty = BindableProperty.Create(nameof(VerticalTextAlignment), typeof(TextAlignment), typeof(TextAlignmentButton));


    public TextAlignment HorizontalTextAlignment
    {
        get => (TextAlignment)GetValue(HorizontalTextAlignmentProperty);
        set => SetValue(HorizontalTextAlignmentProperty, value);
    }

    public TextAlignment VerticalTextAlignment
    {
        get => (TextAlignment)GetValue(VerticalTextAlignmentProperty);
        set => SetValue(VerticalTextAlignmentProperty, value);
    }
}

internal class TextAlignmentButtonHandler : ButtonHandler
{
	public override void UpdateValue(string property)
	{
		base.UpdateValue(property);
		if (property == TextAlignmentButton.HorizontalTextAlignmentProperty.PropertyName ||
            property == TextAlignmentButton.VerticalTextAlignmentProperty.PropertyName)
        {
            OnTextAlignmentPropertyChanged();
        }
	}


#if ANDROID
	protected override void ConnectHandler(MaterialButton platformView)
	{
		base.ConnectHandler(platformView);
		OnTextAlignmentPropertyChanged();
	}
#elif IOS
	protected override void ConnectHandler(UIButton platformView)
	{
		base.ConnectHandler(platformView);
		OnTextAlignmentPropertyChanged();
	}
#elif WINDOWS
    protected override void ConnectHandler(Microsoft.UI.Xaml.Controls.Button platformView)
    {
        base.ConnectHandler(platformView);
        OnTextAlignmentPropertyChanged();
    }
#endif

	private void OnTextAlignmentPropertyChanged()
	{
		if (VirtualView is TextAlignmentButton virtualButton)
		{
#if ANDROID
			var horizontalFlag = virtualButton.HorizontalTextAlignment switch
			{
				TextAlignment.Start => global::Android.Views.GravityFlags.Left,
				TextAlignment.Center => global::Android.Views.GravityFlags.CenterHorizontal,
				TextAlignment.End => global::Android.Views.GravityFlags.Right,
				_ => global::Android.Views.GravityFlags.Center
			};

			var verticalFlag = virtualButton.VerticalTextAlignment switch
			{
				TextAlignment.Start => global::Android.Views.GravityFlags.Top,
				TextAlignment.Center => global::Android.Views.GravityFlags.CenterVertical,
				TextAlignment.End => global::Android.Views.GravityFlags.Bottom,
				_ => global::Android.Views.GravityFlags.Center
			};

			PlatformView.Gravity = horizontalFlag | verticalFlag;
#elif IOS
			PlatformView.HorizontalAlignment = virtualButton.HorizontalTextAlignment switch
            {
                TextAlignment.Start => UIControlContentHorizontalAlignment.Left,
                TextAlignment.Center => UIControlContentHorizontalAlignment.Center,
                TextAlignment.End => UIControlContentHorizontalAlignment.Right,
                _ => UIControlContentHorizontalAlignment.Center,
            };
            
            PlatformView.VerticalAlignment = virtualButton.VerticalTextAlignment switch
            {
                TextAlignment.Start => UIControlContentVerticalAlignment.Top,
                TextAlignment.Center => UIControlContentVerticalAlignment.Center,
                TextAlignment.End => UIControlContentVerticalAlignment.Bottom,
                _ => UIControlContentVerticalAlignment.Center,
            };
#elif WINDOWS
			PlatformView.HorizontalContentAlignment = virtualButton.HorizontalTextAlignment switch
			{
				TextAlignment.Start => Microsoft.UI.Xaml.HorizontalAlignment.Left,
				TextAlignment.Center => Microsoft.UI.Xaml.HorizontalAlignment.Center,
				TextAlignment.End => Microsoft.UI.Xaml.HorizontalAlignment.Right,
				_ => Microsoft.UI.Xaml.HorizontalAlignment.Center,
			};

			PlatformView.VerticalContentAlignment = virtualButton.VerticalTextAlignment switch
			{
				TextAlignment.Start => Microsoft.UI.Xaml.VerticalAlignment.Top,
				TextAlignment.Center => Microsoft.UI.Xaml.VerticalAlignment.Center,
				TextAlignment.End => Microsoft.UI.Xaml.VerticalAlignment.Bottom,
				_ => Microsoft.UI.Xaml.VerticalAlignment.Center,
			};
#endif
		}
	}
}