Xamarin change page from a renderer Button

Question

I have a renderer button in iOS and what I am trying to do is to trigger another page into the stack when it gets a swipe gesture.

if I implement that on my MainPage, for the Clicked it is quiete straight forward. as I can use "this"

    public class MainPage : ContentPage
    {
        public MainPage ()
        {
            // Button bottom 1
            var button = new Button { 
                Text = "button",
                HeightRequest = 60,
                HorizontalOptions = LayoutOptions.FillAndExpand,
                VerticalOptions = LayoutOptions.CenterAndExpand,

            };
            button.Clicked += async (sender, e) => {
                await this.Navigation.PushModalAsync(new nextPage());
            };
       }
}

but How could I do this in a rendered button in iOS.

my renderer button is like this:

public class MYButtonRenderer : ButtonRenderer
    {
        UISwipeGestureRecognizer swipeGestureRecognizerUp;

        protected override void OnElementChanged (ElementChangedEventArgs<Button> e)
        {
            base.OnElementChanged (e);

            swipeGestureRecognizerUp = new UISwipeGestureRecognizer (() => onSwipeUp());
            swipeGestureRecognizerUp.Direction = UISwipeGestureRecognizerDirection.Up;

            if (e.NewElement == null) 
            {

                if (swipeGestureRecognizerUp != null) 
                {
                    this.RemoveGestureRecognizer (swipeGestureRecognizerUp);
                }
            }

            if (e.OldElement == null) 
            {
                this.AddGestureRecognizer (swipeGestureRecognizerUp);
            }
        }

        private void onSwipeUp()
        {
           //here it's where I would like to change the page to a new one.
        }
    }

is this possible?? Thank you for your time.

Answer 1

A nice way to do this would be to combine your custom renderer with a custom button view. Your custom view could have a swipe event to which you can subscribe. Of course, you could create a custom delegate if necessary as well, to pass custom event data, but I've kept this example simple.

public class CustomButton : Button
{
    public event EventHandler OnSwipeUp;

    public void FireSwipeUp()
    {
        var swipeUp = OnSwipeUp;
        if (swipeUp != null)
            swipeUp(this, EventArgs.Empty);
    }
}

From your custom renderer, you can fire the custom event by calling the FireSwipeUp method.

private void onSwipeUp()
{
    ((CustomButton)Element).FireSwipeUp();
}

Now you can subscribe to your custom OnSwipeUp event from within your MainPage class, just as you do with Clicked.

// Button bottom 1
var button = new CustomButton { 
    Text = "button",
    HeightRequest = 60,
    HorizontalOptions = LayoutOptions.FillAndExpand,
    VerticalOptions = LayoutOptions.CenterAndExpand,
};

button.Clicked += async (sender, e) => {
     await this.Navigation.PushModalAsync(new nextPage());
};

button.OnSwipeUp += async (sender, e) => {
     await this.Navigation.PushModalAsync(new nextPage());
};