ios - 优雅地获取当前键盘框架？

Question

是否有一种优雅的方式来获取当前可见的任何 inputView 的框架（大小）？优雅，我的意思是不辞职，然后重新激活第一响应者，因为这会丢弃任何 kbd 状态数据，例如 Shift 键状态。

我目前做的是这样的：

- (CGSize)inputViewSize
{
    __block CGSize result = CGSizeZero;
    UIResponder *firstResponder = [self getFirstResponder];
    id observer = [NSNotificationCenter.defaultCenter addObserverForName:UIKeyboardDidShowNotification object:nil queue:nil usingBlock:^(NSNotification *note)
    {
        result = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue].size;
    }];
    [firstResponder resignFirstResponder];
    [firstResponder becomeFirstResponder];
    [NSNotificationCenter.defaultCenter removeObserver:observer];
    return result;
}

编辑：我应该做的是：

@implementation UIApplication (KeyboardFrame)

static CGRect _keyboardFrame = (CGRect){ (CGPoint){ 0.0f, 0.0f }, (CGSize) { 0.0f, 0.0f } };
+ (CGSize)keyboardSize { return _keyboardFrame.size; }

+ (void)load
{
    [NSNotificationCenter.defaultCenter addObserverForName:UIKeyboardDidShowNotification object:nil queue:nil usingBlock:^(NSNotification *note)
    {
        _keyboardFrame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    }];
    [NSNotificationCenter.defaultCenter addObserverForName:UIKeyboardDidChangeFrameNotification object:nil queue:nil usingBlock:^(NSNotification *note)
    {
        _keyboardFrame = [note.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];
    }];
    [NSNotificationCenter.defaultCenter addObserverForName:UIKeyboardDidHideNotification object:nil queue:nil usingBlock:^(NSNotification *note)
    {
        _keyboardFrame = CGRectZero;
    }];
}

@end

Answer 1

您需要观察键盘通知。如果对键盘框架更改感兴趣，您可以利用以下两个通知：

UIKeyboardWillChangeFrameNotification 
UIKeyboardDidChangeFrameNotification