AVAudioSession.Notifications.ObserveRouteChange 方法

定义

命名空间:

AVFoundation

程序集:

Xamarin.iOS.dll

重载

ObserveRouteChange(EventHandler<AVAudioSessionRouteChangeEventArgs>)	常量的强类型通知 RouteChangeNotification 。
ObserveRouteChange(NSObject, EventHandler<AVAudioSessionRouteChangeEventArgs>)	常量的强类型通知 RouteChangeNotification 。

ObserveRouteChange(EventHandler<AVAudioSessionRouteChangeEventArgs>)

常量的强类型通知 RouteChangeNotification 。

public static Foundation.NSObject ObserveRouteChange (EventHandler<AVFoundation.AVAudioSessionRouteChangeEventArgs> handler);

static member ObserveRouteChange : EventHandler<AVFoundation.AVAudioSessionRouteChangeEventArgs> -> Foundation.NSObject

参数

handler

EventHandler<AVAudioSessionRouteChangeEventArgs>

发布通知时调用的方法。

返回

NSObject

令牌对象，可用于停止接收通知，方法是释放通知或将其传递给 RemoveObservers(IEnumerable<NSObject>)

注解

以下示例演示开发人员如何在代码中使用此方法：

//
// Lambda style
//

// listening
notification = AVAudioSession.Notifications.ObserveRouteChange ((sender, args) => {
    /* Access strongly typed args */
    Console.WriteLine ("Notification: {0}", args.Notification);

    Console.WriteLine ("Reason", args.Reason);
    Console.WriteLine ("PreviousRoute", args.PreviousRoute);
});

// To stop listening:
notification.Dispose ();

//
//Method style
//
NSObject notification;
void Callback (object sender, AVFoundation.AVAudioSessionRouteChangeEventArgs args)
{
    // Access strongly typed args
    Console.WriteLine ("Notification: {0}", args.Notification);

    Console.WriteLine ("Reason", args.Reason);
    Console.WriteLine ("PreviousRoute", args.PreviousRoute);
}

void Setup ()
{
    notification = AVAudioSession.Notifications.ObserveRouteChange (Callback);
}

void Teardown ()
{
    notification.Dispose ();
}

ObserveRouteChange(NSObject, EventHandler<AVAudioSessionRouteChangeEventArgs>)

常量的强类型通知 RouteChangeNotification 。

public static Foundation.NSObject ObserveRouteChange (Foundation.NSObject objectToObserve, EventHandler<AVFoundation.AVAudioSessionRouteChangeEventArgs> handler);

static member ObserveRouteChange : Foundation.NSObject * EventHandler<AVFoundation.AVAudioSessionRouteChangeEventArgs> -> Foundation.NSObject

参数

objectToObserve

NSObject

要观察的特定对象。

handler

EventHandler<AVAudioSessionRouteChangeEventArgs>

当通知发生时响应通知的处理程序。

返回

NSObject

令牌对象，可用于停止接收通知，方法是释放通知或将其传递给 RemoveObservers(IEnumerable<NSObject>)

注解

此方法可用于订阅 RouteChangeNotification 通知。

// Listen to all notifications posted for any object
var token = AVAudioSession.Notifications.ObserveRouteChange ((notification) => {
	Console.WriteLine ("Observed RouteChangeNotification!");
};

// Listen to all notifications posted for a single object
var token = AVAudioSession.Notifications.ObserveRouteChange (objectToObserve, (notification) => {
	Console.WriteLine ($"Observed RouteChangeNotification for {nameof (objectToObserve)}!");
};

// Stop listening for notifications
token.Dispose ();