如何检查MAUI中前台服务是否正在运行

Question

我想检查前台服务是否已经在 Android 的 MAUI 中运行，那么我不必执行任何操作，但如果没有运行，我会自动启动它。我尝试了 Intent.Action，但它总是显示错误，即使前台服务正在运行，因为它显示定期警报。

Answer 1

您可以使用 Android.OS.Binder 来实现此目的，这将使您能够与您的服务进行通信。下面，我创建了一个简化的示例，如何实现这一点：

实现 OnBind 和 OnUnbind 的自定义服务：

[Service]
public class MyService : Service
{
    private const string _channelId = "123";
    private const int _notifID = 333;
    public bool IsServiceRunning { get; set; }

    public override IBinder OnBind(Intent intent)
    {
        IBinder _binder = new ServiceBinder(this);
        StartService();
        return _binder;
    }

    public override bool OnUnbind(Intent intent)
    {
        IsServiceRunning = false;
        return base.OnUnbind(intent);
    }

    public override void OnDestroy()
    {
        base.OnDestroy();
    }

    public void StartService()
    {
        Notification notification = CreateNotification();
        StartForeground(_notifID, notification);
        IsServiceRunning = true;
    }

    public Notification CreateNotification()
    {
        Context context = Platform.AppContext;

        var intent = new Intent(context, typeof(MainActivity));
        intent.AddFlags(ActivityFlags.SingleTop);

        var pendingIntent = PendingIntent.GetActivity(context, 111, intent, PendingIntentFlags.Immutable);

        var notificationBuilder = new NotificationCompat.Builder(context, _channelId)
            .SetContentTitle("ForegroundService")
            .SetContentText("Message")
            .SetSmallIcon(Resource.Drawable.dotnet_bot)
            .SetOngoing(true)
            .SetContentIntent(pendingIntent);

        if (Build.VERSION.SdkInt >= BuildVersionCodes.O)
        {
            NotificationChannel notificationChannel = new NotificationChannel(_channelId, "Title", NotificationImportance.High);
            notificationChannel.SetShowBadge(true);

            var notificationManager = context.GetSystemService(Context.NotificationService) as NotificationManager;
            if (notificationManager != null)
            {
                notificationBuilder.SetChannelId(_channelId);
                notificationManager.CreateNotificationChannel(notificationChannel);
            }
        }

        return notificationBuilder.Build();
    }
}

服务连接：

public class MyServiceConnection : Java.Lang.Object, IServiceConnection
{
    public ServiceBinder Binder { get; set; }

    public void OnServiceConnected(ComponentName name, IBinder service)
    {
        Binder = (ServiceBinder)service;
    }

    public void OnServiceDisconnected(ComponentName name)
    {
    }

    public MyService GetService()
    {
        if (Binder == null)
            return null;

        return Binder.GetService();
    }
}

public class ServiceBinder : Binder
{
    private MyService _service;

    public ServiceBinder(MyService service)
    {
        _service = service;
    }

    public MyService GetService()
    {
        return _service;
    }
}

ForgroundService 用于启动服务并检查其是否正在运行：

public class ForegroundService
{
    private readonly MyServiceConnection _serviceConnection;

    public ForegroundService(MyServiceConnection serviceConnection)
    {
        _serviceConnection = serviceConnection;
    }

    public void StartForegroundService()
    {
        Context context = Platform.AppContext;
        Intent intent = new(context, typeof(MyService));
        context.BindService(intent, _serviceConnection, Bind.AutoCreate);
    }

    public bool IsForegroundServiceRunning()
    {
        if (_serviceConnection.GetService() == null || !_serviceConnection.GetService().IsServiceRunning)
            return false;

        return true;
    }
}

服务可以在代码中运行和检查：

MyServiceConnection msc = new MyServiceConnection();
ForegroundService fs = new ForegroundService(msc);
fs.IsForegroundServiceRunning();