UIApplication.DidReceiveMemoryWarningNotification 属性
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
DidReceiveMemoryWarning 的通知常量
[Foundation.Advice("Use UIApplication.Notifications.ObserveDidReceiveMemoryWarning helper method instead.")]
[Foundation.Field("UIApplicationDidReceiveMemoryWarningNotification", "UIKit")]
public static Foundation.NSString DidReceiveMemoryWarningNotification { get; }
member this.DidReceiveMemoryWarningNotification : Foundation.NSString
属性值
NSString 常量应用作 NSNotificationCenter 的令牌。
- 属性
注解
此常量可用于注册 NSNotificationCenter 此通知的侦听器。 这是 NSString 而不是字符串,因为这些值可以用作某些本机库中的标记,而不是纯粹用于其实际字符串内容。 回调的“notification”参数包含特定于通知类型的额外信息。
如果要订阅此通知,可以使用方便UIApplication.Notifications。M:UIKit.UIKit.UIApplication.Notifications.ObserveDidReceiveMemoryWarning* 方法,该方法提供对通知参数的强类型访问。
以下示例演示如何使用强类型 Notifications 类,以从通知中的可用属性中排除猜测:
//
// Lambda style
//
// listening
notification = UIApplication.Notifications.ObserveDidReceiveMemoryWarning ((sender, args) => {
/* Access strongly typed args */
Console.WriteLine ("Notification: {0}", args.Notification);
});
// To stop listening:
notification.Dispose ();
//
// Method style
//
NSObject notification;
void Callback (object sender, Foundation.NSNotificationEventArgs args)
{
// Access strongly typed args
Console.WriteLine ("Notification: {0}", args.Notification);
}
void Setup ()
{
notification = UIApplication.Notifications.ObserveDidReceiveMemoryWarning (Callback);
}
void Teardown ()
{
notification.Dispose ();
}
以下示例演示如何将通知与 DefaultCenter API 配合使用:
// Lambda style
NSNotificationCenter.DefaultCenter.AddObserver (
UIApplication.DidReceiveMemoryWarningNotification, (notification) => {Console.WriteLine ("Received the notification UIApplication", notification); }
// Method style
void Callback (NSNotification notification)
{
Console.WriteLine ("Received a notification UIApplication", notification);
}
void Setup ()
{
NSNotificationCenter.DefaultCenter.AddObserver (UIApplication.DidReceiveMemoryWarningNotification, Callback);
}