应用程序关闭时推送通知

Question

我想用Xamarin格式的C#创建一个基于文本的Android游戏。

在故事中，我想设置角色任务，这需要一些时间，例如“我去挖这个洞，完成后给你打电话。”

如何将通知设置为在设置的时间之后显示？例如，上述声明可能需要10分钟，然后用户收到继续游戏的通知？

我一周前才开始做C#，所以如果这是noobish，或者已经被问到了，我道歉。我到处都找过，但有几种类型的通知，当我试图理解它时，似乎我在读法语。

Answer 1

>

将此行添加到您的AndroidManifest。xml

<uses-permission android:name="android.permission.WAKE_LOCK" />

在Android项目中实现BroadcastRecector

[BroadcastReceiver]
public class NotificationBroadcastReceiver : BroadcastReceiver
{
  private ApprovalDataStore _approvalDataStore => DependencyService.Get<ApprovalDataStore>();

  public override async void OnReceive(Context context, Intent intent)
  {
     var pm = PowerManager.FromContext(context);
     var wakeLock = pm.NewWakeLock(WakeLockFlags.Partial, "GCM Broadcast Reciever Tag");
     wakeLock.Acquire();

     //Write your code here

     // When you are finished
     wakeLock.Release();
  }
}

Answer 2

首先，我将在PCL项目中创建两个接口：

public interface IAlarm {
    void SetAlarm();
}

public interface INotification {
    void Notify(LocalNotification notification);
}

然后，在Android项目中，创建以下实现：

报警助手

[assembly: Dependency(typeof(AlarmHelper))]
namespace Test.Droid
{
    class AlarmHelper: IAlarm
    {
        public void SetAlarm(int minutes)
        {
            var alarmTime = Calendar.Instance;
            alarmTime.Add(CalendarField.Minute, minutes);

            var intent = new Intent(Android.App.Application.Context, typeof(ScheduledAlarmHandler));
            var pendingIntent = PendingIntent.GetBroadcast(Android.App.Application.Context, 0, intent, PendingIntentFlags.CancelCurrent);
            var alarmManager = Android.App.Application.Context.GetSystemService(Context.AlarmService) as AlarmManager;

            alarmManager.Set(AlarmType.RtcWakeup, alarmTime.TimeInMillis, pendingIntent); 
        }
    }
}

通知助手

[assembly: Dependency(typeof(NotificationHelper))]
namespace Test.Droid
{
    class NotificationHelper : INotification
    {
        public void Notify (string title, string text)
        {            
            NotificationManager notificationManager = (NotificationManager) Android.App.Application.Context.GetSystemService(Context.NotificationService);

            Intent intent = new Intent(Android.App.Application.Context, typeof(MainActivity));
            PendingIntent pIntent = PendingIntent.GetActivity(Android.App.Application.Context, 0, intent, PendingIntentFlags.OneShot);

            Notification nativeNotification = new Notification();

            var builder = new NotificationCompat.Builder(Android.App.Application.Context)
            .SetContentTitle(title)
            .SetContentText(text)
            .SetSmallIcon(Resource.Drawable.ic_notif) // 24x24 dp
            .SetLargeIcon(BitmapFactory.DecodeResource(Android.App.Application.Context.Resources, Android.App.Application.Context.ApplicationInfo.Icon))
            .SetPriority((int)NotificationPriority.Default)
            .SetAutoCancel(true)
            .SetContentIntent(pIntent);

            notificationManager.Notify(0, builder.Build()); // Id 0 can be random
        }
    }
}

当等待时间结束时，将调用BroadCastRecector：

[BroadcastReceiver]
class ScheduledAlarmHandler : WakefulBroadcastReceiver
{
    public override void OnReceive(Context context, Intent intent)
    {
        // Implement quick checking logic here if notification is still required, plus its tittle and text
        // you have 10 seconds max in this method and cannot use 'await'

        var notificationHelper = new NotificationHelper();
        notificationHelper.Notify("Title","Text");
    }
}

在PCL项目游戏逻辑中，您可以按如下方式设置新警报：

alarmHelper = DependencyService.Get<IAlarm>();
alarmSetter.SetAlarm(10); // 10 minutes from now

我故意把闹钟分开