public static async Task DisplayAlert(string title, string message, string cancel)
{
var tcs = new TaskCompletionSource <bool>();
Device.BeginInvokeOnMainThread(async() =>
{
var sourceView = CurrentView == null ? m_homeView : CurrentView;
await CurrentView.DisplayAlert(title, message, cancel);
tcs.SetResult(true);
});
await tcs.Task;
}