ios - 隐藏/显示方法时的UIKeyboard？

Question

当键盘动画到一半以完全显示/隐藏时，是否有任何代码/方法可以捕获？在调用 keyboardDidShow 通知之前，当键盘半可见时，我需要执行一些操作。非常感谢任何帮助。提前致谢。

Answer 1

没有内置的方法。但是，正如@Aaron Brager 指出的那样，您可以从通知UIKeyboardAnimationDurationUserInfoKey的用户信息中获取键盘演示动画的持续时间。UIKeyboardWillShowNotification然后您所要做的就是将该值除以 2，并将您的操作延迟执行该数量。这是一个例子：

- (void)keyBoardWillShow:(NSNotification *)notification
{
    NSTimeInterval duration = [self keyboardAnimationDurationForNotification:notification];

    double delayInSeconds = duration / 2.0;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
    dispatch_after(popTime, dispatch_get_main_queue(), ^(void){

    });
}

- (NSTimeInterval)keyboardAnimationDurationForNotification:(NSNotification*)notification
{
    NSDictionary *info = [notification userInfo];
    NSValue *value = [info objectForKey:UIKeyboardAnimationDurationUserInfoKey];
    NSTimeInterval duration = 0;
    [value getValue:&duration];
    return duration;
}

- (void)viewWillAppear:(BOOL)animated
{

    [super viewWillAppear:animated];

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

- (void)viewDidDisappear:(BOOL)animated
{
    [super viewDidDisappear:animated];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:UIKeyboardWillShowNotification object:nil];
}