OBJ-C-返回错误的键盘高度？

Question

我正在尝试获取iOS键盘的高度，以便在为键盘设置动画时可以向上移动视图。 但是，我不断获得返回的值258（这是不正确的，因为它将我的视图推得太高了？）为什么会发生这种情况？ 代码如下：

ViewController.m

-(void)viewDidLoad {

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardWillChange:) name:UIKeyboardWillChangeFrameNotification object:nil];

}
    - (void)keyboardWillChange:(NSNotification *)notification {

        NSDictionary* keyboardInfo = [notification userInfo];

        NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameEndUserInfoKey];

        CGRect keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
      self.keyboardHeight = keyboardFrameBeginRect.size.height;


    }

    - (void) animateTextView:(BOOL) up
    {

        const int movementDistance = self.keyboardHeight;

        const float movementDuration = 0.3f;
        int movement= movement = (up ? -movementDistance : movementDistance);


        [UIView beginAnimations: @"anim" context: nil];
        [UIView setAnimationBeginsFromCurrentState: YES];
        [UIView setAnimationDuration: movementDuration];

        self.upView.frame = CGRectOffset(self.upView.frame, 0, movement);
        [UIView setAnimationDidStopSelector:@selector(afterAnimationStops)];
        [UIView commitAnimations];

    }

Answer 1

要获得键盘的高度，应使用UIKeyboardWillShowNotification或UIKeyboardDidShowNotification代替UIKeyboardWillChangeFrameNotification.

-(void)viewDidLoad {

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

}

如果使用UITabBarController ，则必须计算不带标签栏高度的框架。 您可以使用以下代码获取标签栏的高度。

self.tabBarController.tabBar.frame.height

Answer 2

您应该注册UIKeyboardWillShowNotification以便观察键盘高度。

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

2）您也可以尝试以下代码：

(void)keyboardWillChange:(NSNotification *)notification 
{
    NSDictionary* keyboardInfo = [notification userInfo];
    NSValue* keyboardFrameBegin = [keyboardInfo valueForKey:UIKeyboardFrameBeginUserInfoKey];
    CGRect keyboardFrameBeginRect = [keyboardFrameBegin CGRectValue];
}