C# Android: 如何在服务中获取广播接收器？

Question

我正在开发一个在xamarin.android中的无障碍服务。 一切都很好，但我想在服务上添加广播接收器。 我知道我必须从广播接收器派生我的无障碍服务，但这是不可能的，因为该服务已经从Android.AccessibilityService派生。 实际上，问题在于，当用户在主活动上进行某些配置更改时，我希望触发一个广播接收器，而我的无障碍服务应该监听此广播接收器。 所以，有什么建议吗？

- user4246624

---

创建一个新的BroadcastReceiver类，当您从活动中启动广播时，接收器将被触发，然后在其中启动您的辅助功能服务。 - MatPag

Answer 1

在你的 Service 中，定义一个内部类 BroadcastReceiver，在你的 Service 构造函数中创建并注册这个 BroadcastReceiver。

Service 嵌入 BroadcastReceiver 示例：

[Service(Label = "StackOverflowService")]
[IntentFilter(new String[] { "com.yourpackage.StackOverflowService" })]
public class StackOverflowService : Service
{
    public const string BROADCASTFILTER = "com.yourpackage.intent.action.IMAGEOPTIMIZER";
    IBinder binder;
    StackOverflowServiceBroadcastReceiver broadcastReceiver;

    public StackOverflowService()
    {
        broadcastReceiver = new StackOverflowServiceBroadcastReceiver(this);
        RegisterReceiver(broadcastReceiver, new IntentFilter(BROADCASTFILTER));
    }

    public override StartCommandResult OnStartCommand(Intent intent, StartCommandFlags flags, int startId)
    {
        return StartCommandResult.NotSticky;
    }

    public override IBinder OnBind(Intent intent)
    {
        binder = new StackOverflowServiceBinder(this);
        return binder;
    }

    [IntentFilter(new[] { BROADCASTFILTER })]
    class StackOverflowServiceBroadcastReceiver : BroadcastReceiver
    {
        StackOverflowService service;
        public StackOverflowServiceBroadcastReceiver(StackOverflowService service) : base()
        {
            this.service = service;
        }

        public override void OnReceive(Context context, Intent intent)
        {
            var stack = intent.GetStringExtra("Stack");
            Log.Debug("SO", $"{BROADCASTFILTER} Received : {stack}");
            // access your service via the "service" var...
        }
    }
}

public class StackOverflowServiceBinder : Binder
{
    readonly StackOverflowService service;

    public StackOverflowServiceBinder(StackOverflowService service)
    {
        this.service = service;
    }

    public StackOverflowService GetStackOverflowService()
    {
        return service;
    }
}

使用方法：

var intentForService = new Intent(StackOverflowService.BROADCASTFILTER)
    .PutExtra("Stack", "Overflow");
Application.Context.SendBroadcast(intentForService);

- SushiHangover