Xamarin forms navigation back button

问题

I am a newbie in xamarin forms app development, currently, I am facing an issue in overriding the toolbar back button onclick. In ios, I am able to achieve but in android its not working can anyone help me out on how to achieve this in my project.

回答1:

By default it works on iOS and on Android physical back button only. If you want to also support the navigation bar button, you need to use custom platform logic. Take a look on this blog post: Let’s Override Navigation Bar back button click in Xamarin For. He creates a common content page with custom action for back button:

 public class CoolContentPage : ContentPage
    {
        /// <summary>
        /// Gets or Sets the Back button click overriden custom action
        /// </summary>
        public Action CustomBackButtonAction { get; set; }

        public static readonly BindableProperty EnableBackButtonOverrideProperty =
               BindableProperty.Create(
               nameof(EnableBackButtonOverride),
               typeof(bool),
               typeof(CoolContentPage),
               false);

        /// <summary>
        /// Gets or Sets Custom Back button overriding state
        /// </summary>
        public bool EnableBackButtonOverride
        {
            get
            {
                return (bool)GetValue(EnableBackButtonOverrideProperty);
            }
            set
            {
                SetValue(EnableBackButtonOverrideProperty, value);
            }
        }
    }

And then he calls CustomBackAction inside OnOptionsItemSelected method in Anroid code.

来源：https://stackoverflow.com/questions/49810589/xamarin-forms-navigation-back-button