iOS 9.0 - 获取键盘将显示/隐藏来自其他应用程序的通知

Question

我的 View Controller 注册到键盘通知(keyboardWillShow、keyboardWillHide)。

我启动我的应用程序。它显示注册到键盘通知的 View Controller 。键盘不可见。

我切换到短信应用程序并开始编写文本。在我写作时，我的应用会收到通知。通知在屏幕顶部显示为横幅。

当我点击横幅时，我的应用程序会打开并立即收到键盘通知。

据我所知，这个键盘通知与短信的键盘有关。

如何确定键盘事件是否来 self 的应用？

Answer 1

您可以在 viewWillDisappear 中删除对观察者的监听(键盘通知)，并可以在 viewWillAppear 中再次开始监听观察者，这可能会解决问题

- (void)registerForKeyboardNotifications
{
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWasShown:)
                                                 name:UIKeyboardWillShowNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillBeHidden:)
                                                 name:UIKeyboardWillHideNotification object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(applicationWillEnterBackground:)
                                                 name:UIApplicationWillResignActiveNotification
                                               object:nil];
}

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [self registerForKeyboardNotifications];
}

- (void)deregisterForKeyboardNotifications {
    NSNotificationCenter *center = [NSNotificationCenter defaultCenter];
   [center removeObserver:self name:UIKeyboardWillShowNotification object:nil];
   [center removeObserver:self name:UIKeyboardWillHideNotification object:nil];
   [center removeObserver:self name:UIApplicationWillResignActiveNotification object:nil];
}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    [self deregisterForKeyboardNotifications];
}