目前正在开发一个我想使用AppCompat的项目,并且在大多数页面上都要求设置标题和副标题.
它根本不能使用AppCompat – 既不设置属性也不使用自定义视图.
不使用AppCompat时,两者都按预期工作.完整的源代码可用here所以如果你好奇的话就运行应用程序:)
- using System.ComponentModel;
- using Android.App;
- using Android.Widget;
- using App1.Droid.Renderers;
- using Xamarin.Forms;
- using Xamarin.Forms.Platform.Android;
- #if __APPCOMPAT__
- using NavigationRenderer = Xamarin.Forms.Platform.Android.AppCompat.NavigationPageRenderer;
- #else
- using NavigationRenderer = Xamarin.Forms.Platform.Android.NavigationRenderer;
- #endif
- [assembly: ExportRenderer(typeof(NavigationPage),typeof(NavigationPageRenderer))]
- namespace App1.Droid.Renderers
- {
- public class NavigationPageRenderer : NavigationRenderer
- {
- protected override void OnElementChanged(ElementChangedEventArgs<NavigationPage> e)
- {
- base.OnElementChanged(e);
- SetCustomView(e.NewElement.CurrentPage.GetType().Name);
- }
- private void SetCustomView(string view)
- {
- var activity = (Activity)Context;
- #if __APPCOMPAT__
- var actionBar = ((FormsAppCompatActivity)Context).SupportActionBar;
- #else
- var actionBar = activity.ActionBar;
- #endif
- actionBar.Title = view;
- actionBar.Subtitle = " -> " + view;
- var abv = new LinearLayout(activity)
- {
- Orientation = Orientation.Vertical
- };
- var main = new TextView(activity)
- {
- Text = view,};
- main.SetTextColor(Color.Aqua.ToAndroid());
- main.SetPadding(4,4,2,6);
- abv.AddView(main);
- abv.AddView(new TextView(activity)
- {
- Text = " -> " + view
- });
- actionBar.SetDisplayShowCustomEnabled(true);
- actionBar.CustomView = abv;
- }
- protected override void OnElementPropertyChanged(object sender,PropertyChangedEventArgs e)
- {
- base.OnElementPropertyChanged(sender,e);
- if (e.PropertyName.Equals("CurrentPage"))
- {
- SetCustomView(((NavigationPage)sender).CurrentPage.GetType().Name);
- }
- }
- }
- }
解决方法
所以它看起来像NavigationPage
uses its own Toolbar instance.这就是为什么在SupportActionBar上设置属性没有做任何事情.
我能够通过覆盖OnViewAdded()来获得它的工作,以便在添加时获得对新工具栏的引用：
- public override void OnViewAdded(Android.Views.View child)
- {
- base.OnViewAdded(child);
- if (child.GetType() == typeof(Support.Toolbar))
- toolbar = (Support.Toolbar)child;
- }
然后使用SetCustomView()内部的引用来设置Subtitle,因为Title已经自动设置.
