UIKeyboard.WillShowNotification 属性

定义

命名空间:

UIKit

程序集:

Xamarin.iOS.dll

WillShow 的通知常量

[Foundation.Advice("Use UIKeyboard.Notifications.ObserveWillShow helper method instead.")]
[Foundation.Field("UIKeyboardWillShowNotification", "UIKit")]
[ObjCRuntime.Unavailable(ObjCRuntime.PlatformName.TvOS, ObjCRuntime.PlatformArchitecture.All, null)]
public static Foundation.NSString WillShowNotification { [ObjCRuntime.Unavailable(ObjCRuntime.PlatformName.TvOS, ObjCRuntime.PlatformArchitecture.All, null)] get; }

member this.WillShowNotification : Foundation.NSString

属性值

NSString

NSString 常量应用作 NSNotificationCenter 的令牌。

属性

AdviceAttribute FieldAttribute UnavailableAttribute

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，可以使用便捷 UIKeyboard.Notifications的 .ObserveWillShow 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 = UIKeyboard.Notifications.ObserveWillShow ((sender, args) => {
    /* Access strongly typed args */
    Console.WriteLine ("Notification: {0}", args.Notification);

    Console.WriteLine ("FrameBegin", args.FrameBegin);
    Console.WriteLine ("FrameEnd", args.FrameEnd);
    Console.WriteLine ("AnimationDuration", args.AnimationDuration);
    Console.WriteLine ("AnimationCurve", args.AnimationCurve);
});

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

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

    Console.WriteLine ("FrameBegin", args.FrameBegin);
    Console.WriteLine ("FrameEnd", args.FrameEnd);
    Console.WriteLine ("AnimationDuration", args.AnimationDuration);
    Console.WriteLine ("AnimationCurve", args.AnimationCurve);
}

void Setup ()
{
    notification = UIKeyboard.Notifications.ObserveWillShow (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 (
        UIKeyboard.WillShowNotification, (notification) => {Console.WriteLine ("Received the notification UIKeyboard", notification); }


// Method style
void Callback (NSNotification notification)
{
    Console.WriteLine ("Received a notification UIKeyboard", notification);
}

void Setup ()
{
    NSNotificationCenter.DefaultCenter.AddObserver (UIKeyboard.WillShowNotification, Callback);
}