[Bug] [iOS] Button stays in Pressed state if the touch-up event occurs outside

[hichamboushaba]

Description

If you tap a button, then drag your finger outside it, then the button will stay in the "Pressed" state.

Steps to Reproduce

1. Tap a button
2. Drag your finger outside the button
3. Lift up your finger

Expected Behavior

The button will go to the state "Normal"

Actual Behavior

The button will stay in the state "Pressed"

Basic Information

• Version with issue: 4.7.0.1080

The cause is clear from the ButtonRenderer, we only listen to the TouchUpInside event, so SendReleased is not called when TouchUpOutside occurs.
As a workaround I'm using this Renderer in my project:

    public class ButtonRenderer : Xamarin.Forms.Platform.iOS.ButtonRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Button> e)
        {
            base.OnElementChanged(e);
            if (e.NewElement != null)
            {
                Control.TouchUpOutside += OnTouchUpOutside;
            }
        }

        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
            if (!disposing) return;

            if (Control != null)
            {
                Control.TouchUpOutside -= OnTouchUpOutside;
            }
        }

        private void OnTouchUpOutside(object sender, EventArgs e)
        {
            Element?.SendReleased();
        }

[ChristopherStephan]

According to the release notes this issue is fixed in 4.8.0.1269 (https://docs.microsoft.com/en-us/xamarin/xamarin-forms/release-notes/4.8/4.8.0-pre3#issues-fixed) - which is a wrong information: the issue is still reproducible in this version. By updating Xamarin.Forms to 4.8.0.1687 we could confirm that this bug is fixed.