Xamarin表單的本地推送通知

Question

我想使用Xamarin表單的DependencyService實現本地推送通知。 這裏的接口：

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

，這裏是Andriod的實施：

[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"); 
     } 
    } 
} 

它是示值誤差在Notification.Builder builder = new Notification.Builder(this)爲：

無法從 'TestMVVM.Droid.NotificationService' 轉換到 'Andriod.Content.Context'

我明白這個問題。 Context允許訪問特定於應用程序的資源和類，以及對應用程序級操作（如啓動活動，廣播和接收意圖等）的上調（請參閱：https://developer.xamarin.com/api/type/Android.Content.Context/#Remarks）。由於它是一個抽象類，我不能創建對象並將其傳遞給構造函數Builder。 如何將上下文傳遞給Builder構造函數？

編輯：感謝您的幫助。它正在工作，但通知不顯示只有聲音正在工作。這裏的代碼：

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"); 
     } 
    } 
}