如何检测键盘何时显示和隐藏

如何检测应用程序中何时显示和隐藏键盘？

在类的 ViewDidLoad 方法中设置监听有关键盘的消息：

// Listen for keyboard appearances and disappearances
[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(keyboardDidShow:)
                                             name:UIKeyboardDidShowNotification
                                           object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardDidHide:)
                                             name:UIKeyboardDidHideNotification
                                           object:nil];

然后在您指定的方法中（在本例中keyboardDidShow and keyboardDidHide）你可以做一些事情：

- (void)keyboardDidShow: (NSNotification *) notif{
    // Do something here
}

- (void)keyboardDidHide: (NSNotification *) notif{
    // Do something here
}