How to include view in NavigationBar of Xamarin Fo

问题:

I need your help !

I work on a mobile development project, cross-platform. I use Visual Studio with Xamarin Forms. I have a SearchBar (Xamarin.Forms class), but, my problem is to include this into the NavigationBar.

Currently, I have a MasterDetailPage and I init this.Detail with new NavigationPage(new customPage()). I have a SearchBar renderer, too. So, I need original NavigationBar (I want to keep the return button) but I would like to add my SearchBar inside.

I would be very grateful if you know of a way to do this especially to android. Thank you in advance !

回答1:

You need to create a custom NavigationRenderer and insert your own UISearchBar into the UIToolbar or SearchView into the ViewGroup:

Xamarin Forms : Renderer Base Classes and Native Controls

As an example of inserting a iOS UISearchBar into the nav bar via a custom NavigationRenderer:

Note: In order to keep things decoupled, using the MessagingCenter allows you to pump messages around without any hardcoding event dependancies within the custom renderer.

[assembly:ExportRenderer (typeof(NavigationPage), typeof(SeachBarNavigationRender))]
namespace Forms.Life.Cycle.iOS
{
    public class SeachBarNavigationRender : NavigationRenderer
    {
        public SeachBarNavigationRender () : base()
        {
        }

        public override void PushViewController (UIViewController viewController, bool animated)
        {
            base.PushViewController (viewController, animated);
            List<UIBarButtonItem> toolbarItem = new List<UIBarButtonItem> ();
            foreach (UIBarButtonItem barButtonItem in TopViewController.NavigationItem.RightBarButtonItems) {
                if ( barButtonItem.Title.Contains( "search")) {
                    UISearchBar search = new UISearchBar (new CGRect (0, 0, 200, 25));
                    search.BackgroundColor = UIColor.LightGray;
                    search.SearchBarStyle = UISearchBarStyle.Prominent;
                    search.TextChanged += (object sender, UISearchBarTextChangedEventArgs e) => {
                        D.WriteLine(e.SearchText);
                        MessagingCenter.Send<object, string> (this, "SearchText", e.SearchText);
                    };
                    barButtonItem.CustomView = search;
                }
                toolbarItem.Add (barButtonItem);
            }
            TopViewController.NavigationItem.RightBarButtonItems = toolbarItem.ToArray ();
        }
    }
}