BaseViewModel.cs

.cs

using System;
using System.Threading.Tasks;

namespace Acelerometro.ViewModel
{
    public class BaseViewModel : ObservableObject
    {
        bool isBusy;

        public bool IsBusy
        {
            get => isBusy;
            set => SetProperty(ref isBusy, value, onChanged: () => OnPropertyChanged(nameof(IsNotBusy)));
        }

        public bool IsNotBusy => !IsBusy;

        public virtual void OnAppearing()
        {
        }

        public virtual void OnDisappearing()
        {
        }

        internal event Func<string, Task> DoDisplayAlert;

        public Task DisplayAlertAsync(string message)
        {
            return DoDisplayAlert?.Invoke(message) ?? Task.CompletedTask;
        }
    }
}