KeyboardInsetsService.cs

using System;
using Microsoft.Maui.ApplicationModel;
using NeuroAccessMaui;
using NeuroAccessMaui.Services;
 
namespace NeuroAccessMaui.Services.UI
{
    public sealed class KeyboardInsetsService : IKeyboardInsetsService, IDisposable
    {
        private readonly IPlatformSpecific platformSpecific;
        private double keyboardHeight;
        private bool isKeyboardVisible;
        private bool isDisposed;
 
        public KeyboardInsetsService(IPlatformSpecific platformSpecific)
        {
            this.platformSpecific = platformSpecific ?? throw new ArgumentNullException(nameof(platformSpecific));
            this.platformSpecific.KeyboardSizeChanged += this.OnKeyboardSizeChanged;
            this.platformSpecific.KeyboardHidden += this.OnKeyboardHidden;
        }
 
        public event EventHandler<KeyboardInsetChangedEventArgs>? KeyboardInsetChanged;
 
        public double KeyboardHeight => this.keyboardHeight;
 
        public bool IsKeyboardVisible => this.isKeyboardVisible;
 
        public void Dispose()
        {
            if (this.isDisposed)
                return;
 
            this.platformSpecific.KeyboardSizeChanged -= this.OnKeyboardSizeChanged;
            this.platformSpecific.KeyboardHidden -= this.OnKeyboardHidden;
            this.isDisposed = true;
        }
 
        private void OnKeyboardSizeChanged(object? sender, KeyboardSizeMessage message)
        {
            double newHeight = Math.Max(0, message.KeyboardSize);
            bool newVisibility = newHeight > 0.5;
 
            if (Math.Abs(newHeight - this.keyboardHeight) < 0.5 && newVisibility == this.isKeyboardVisible)
                return;
 
            this.keyboardHeight = newHeight;
            this.isKeyboardVisible = newVisibility;
            this.RaiseChanged();
        }
 
        private void OnKeyboardHidden(object? sender, KeyboardSizeMessage message)
        {
            if (this.keyboardHeight <= 0 && !this.isKeyboardVisible)
                return;
 
            this.keyboardHeight = 0;
            this.isKeyboardVisible = false;
            this.RaiseChanged();
        }
 
        private void RaiseChanged()
        {
            void Raise()
            {
                this.KeyboardInsetChanged?.Invoke(this, new KeyboardInsetChangedEventArgs(this.keyboardHeight, this.isKeyboardVisible));
            }
 
            if (MainThread.IsMainThread)
                Raise();
            else
                MainThread.BeginInvokeOnMainThread(Raise);
        }
    }
}