android应用副标题,Xamarin.Forms自定义Android NavigationPageRenderer标题和副标题

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 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);

}

}

}

}

编辑：谢谢@jimmgarr.稍微改变代码以保持AppCompbat和“正常模式”之间的交替.该代码可用于here