Xamarin表单的本地推送通知

Question

我想使用Xamarin表单的DependencyService实现本地推送通知。 这里的接口：

public interface INotification 
    { 
     void SetNotification(DateTime notificationDate, TimeSpan notificationTime); 
    } 

，这里是Andriod的实施：

[assembly:Dependency(typeof(NotificationService))] 
namespace TestMVVM.Droid 
{ 
    public class NotificationService : INotification 
    { 
     public void SetNotification(DateTime notificationDate, TimeSpan notificationTime) 
     { 
      Notification.Builder builder = new Notification.Builder(this) 
       .SetContentTitle("Test Notification") 
       .SetContentText("Notification from Xamarin Forms"); 
     } 
    } 
} 

它是示值误差在Notification.Builder builder = new Notification.Builder(this)为：

无法从 'TestMVVM.Droid.NotificationService' 转换到 'Andriod.Content.Context'

我明白这个问题。 Context允许访问特定于应用程序的资源和类，以及对应用程序级操作（如启动活动，广播和接收意图等）的上调（请参阅：https://developer.xamarin.com/api/type/Android.Content.Context/#Remarks）。由于它是一个抽象类，我不能创建对象并将其传递给构造函数Builder。 如何将上下文传递给Builder构造函数？

编辑：感谢您的帮助。它正在工作，但通知不显示只有声音正在工作。这里的代码：

Notification.Builder builder = new Notification.Builder(Xamarin.Forms.Forms.Context) 
       .SetContentTitle("Test Notification") 
       .SetContentText("Notification from Xamarin Forms") 
       .SetDefaults(NotificationDefaults.Sound) 
       .SetWhen(Java.Lang.JavaSystem.CurrentTimeMillis()); 

      Notification notification = builder.Build(); 
      NotificationManager notificationManager = 
             Forms.Context.GetSystemService(Context.NotificationService) as NotificationManager; 
      const int notificationId = 0; 
      notificationManager.Notify(notificationId, notification); 

Answer 1

使用Xamarin.Forms.Forms.Context

[assembly:Dependency(typeof(NotificationService))] 
namespace TestMVVM.Droid 
{ 
    public class NotificationService : INotification 
    { 
     public void SetNotification(DateTime notificationDate, TimeSpan notificationTime) 
     { 
      Notification.Builder builder = new Notification.Builder (Xamarin.Forms.Forms.Context) 
       .SetContentTitle ("Test Notification") 
       .SetSmallIcon(Android.Resource.Drawable.AlertDarkFrame) 
       .SetWhen (Java.Lang.JavaSystem.CurrentTimeMillis()) 
       .SetDefaults (NotificationDefaults.Sound) 
       .SetContentText ("Notification from Xamarin Forms"); 
     } 
    } 
}