Xamarin Forms: DisplayAlert background tap firing the cancel event - xamarin.forms

Question

I am using a DisplayAlert like below in my project.
var answer = await DisplayAlert("Alert", "You are invited to join a group, would you like to accept it or not?", "Accept", "Reject");
if (answer)
{
//accept invitation
}
else
{
//reject invitation
}
Accept and Reject options are working fine. My problem is Reject option is executing when tapping on the background or device back arrow. Is it has a simple solution other than implementing Rg.Plugins.Popup?

Answer 1

I had a similar request once, and I quickly "solved it" with a workaround like this (using DisplayActionSheet):
bool isActionSelected = false;
while(!isActionSelected)
{
string action = await DisplayActionSheet ("You are invited to join a group, would you like to accept it or not?", null, null, "Accept", "Reject");
if (action == "Accept")
{
isActionSelected = true;
//do stuff
}
else if (action == "Reject")
{
isActionSelected = true;
//do stuff
}
else
{
isActionSelected = false;
}
}
This is not suggested, unless you are in a hurry.
So, I would suggest you creating a custom popupView, something like this
<ContentView x:Name="popupView" BackgroundColor="#C0808080" Padding="10, 0" IsVisible="false" AbsoluteLayout.LayoutBounds="0, 0, 1, 1" AbsoluteLayout.LayoutFlags="All">
<StackLayout VerticalOptions="Center" HorizontalOptions="Center">
<StackLayout Orientation="Vertical" HeightRequest="150" WidthRequest="200" BackgroundColor="White">
<Label x:Name="myLabel" TextColor="Black" Text="You are invited to join a group, would you like to accept it or not?" />
<Button Text="Accept" TextTransform="None" Clicked="AcceptClicked" />
<Button Text="Reject" TextTransform="None" Clicked="RejectClicked" />
</StackLayout>
</StackLayout>
</ContentView>
then in .cs
popupView.IsVisible = true;
when you want this to appear.

Answer 2

The only solution - Use DependencyService to implement the alert on each platform .
Interface in Forms
public interface IShowAlertService
{
Task<bool> ShowAlert(string title, string message, string ok, string cancel);
}
Android Implementation
[assembly: Dependency(typeof(ShowAlertService))]
namespace XamarinTableView.Droid
{
class ShowAlertService : IShowAlertService
{
TaskCompletionSource<bool> taskCompletionSource;
public Task<bool> ShowAlert(string title, string message, string ok, string cancel)
{
taskCompletionSource = new TaskCompletionSource<bool>();
Android.App.AlertDialog.Builder dialog = new AlertDialog.Builder(MainActivity.Instance);
AlertDialog alert = dialog.Create();
alert.SetTitle("Title");
alert.SetMessage("Complex Alert");
alert.SetButton("OK", (c, ev) =>
{
// Ok button click task
Console.WriteLine("Okay was clicked");
taskCompletionSource.SetResult(true);
});
alert.SetButton2("CANCEL", (c, ev) => {
Console.WriteLine("Cancel was clicked");
taskCompletionSource.SetResult(false);
});
alert.Show();
return taskCompletionSource.Task;
}
}
}
iOS Implementation
[assembly: Dependency(typeof(ShowAlertService))]
namespace XamarinTableView.iOS
{
class ShowAlertService : IShowAlertService
{
TaskCompletionSource<bool> taskCompletionSource;
public Task<bool> ShowAlert(string title, string message, string ok, string cancel)
{
taskCompletionSource = new TaskCompletionSource<bool>();
var okCancelAlertController = UIAlertController.Create(title, message, UIAlertControllerStyle.Alert);
//Add Actions
okCancelAlertController.AddAction(UIAlertAction.Create(ok, UIAlertActionStyle.Default, alert => {
Console.WriteLine("Okay was clicked");
taskCompletionSource.SetResult(true);
}));
okCancelAlertController.AddAction(UIAlertAction.Create(cancel, UIAlertActionStyle.Cancel, alert => {
Console.WriteLine("Cancel was clicked");
taskCompletionSource.SetResult(false);
}));
UIWindow window = UIApplication.SharedApplication.KeyWindow;
var viewController = window.RootViewController;
//Present Alert
viewController.PresentViewController(okCancelAlertController, true, null);
return taskCompletionSource.Task;
}
}
Consume in Forms
bool isOk = await DependencyService.Get<IShowAlertService>().ShowAlert("Alert", "You have been alerted", "OK", "Cancel");
if (isOk)
{
}
else
{
}
In this way clicking outside the alert will not trigger cancel event .
Refer to DisplayAlert Xamarim forms.