Question

我的故事板上有一个用于显示用户登录表单的视图，因此它看起来像这样：主视图 - ＆gt;滚动视图 - ＆gt;内容视图 - ＆gt;两个文本字段和顶部的登录按钮和一个注册按钮位于视图的底部。我使用自动布局，底部按钮有底部空间约束。当我点击文本字段并出现键盘时，我想滚动视图以将大小更改为可见的rect，但内容大小应保持向下滚动到注册按钮，但当滚动视图的大小更改时按钮会向上移动。我怎么能做我想做的事？

键盘出现时我使用此代码：

- (void)keyboardWillShow:(NSNotification *)aNotification
{
    NSDictionary *info = [aNotification userInfo];
    NSValue *kbFrame = [info objectForKey:UIKeyboardFrameEndUserInfoKey];
    NSTimeInterval animationDuration = [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue];
    CGRect keyboardFrame = [kbFrame CGRectValue];

    CGSize s = self.scrollView.contentSize;
    CGFloat height = keyboardFrame.size.height;
    self.scrollViewBottomLayoutConstraint.constant = height;

    [UIView animateWithDuration:animationDuration animations:^{
        [self.view layoutIfNeeded];
        [self.scrollView setContentSize:s];
    }];
}

Answer 1

尝试单独保留内容大小，而是调整滚动视图的contentInset属性。然后你不必乱用约束。

- (void)keyboardUp:(NSNotification *)notification
{
    NSDictionary *info = [notification userInfo];
    CGRect keyboardRect = [[info objectForKey:UIKeyboardFrameEndUserInfoKey] CGRectValue];
    keyboardRect = [self.view convertRect:keyboardRect fromView:nil];

    UIEdgeInsets contentInset = self.scrollView.contentInset;
    contentInset.bottom = keyboardRect.size.height;
    self.scrollView.contentInset = contentInset;
}

Answer 2

我找到的最好方法是覆盖NSLayoutConstraint，如下所示：

@implementation NHKeyboardLayoutConstraint

- (void) dealloc {
    [[NSNotificationCenter defaultCenter] removeObserver:self];
}

- (void) awakeFromNib {
    [super awakeFromNib];
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(keyboardWillChangeFrame:)
                                                 name:UIKeyboardWillChangeFrameNotification
                                               object:nil];
}

- (void)keyboardWillChangeFrame:(NSNotification *)notification {

    CGRect endKBRect = [notification.userInfo[UIKeyboardFrameEndUserInfoKey] CGRectValue];

    CGFloat animationDuration = [notification.userInfo[UIKeyboardAnimationDurationUserInfoKey] floatValue];
    CGRect frame = [UIApplication sharedApplication].keyWindow.bounds;

    self.constant = frame.size.height - endKBRect.origin.y;


    [UIView animateWithDuration:animationDuration animations:^{
        [[UIApplication sharedApplication].keyWindow layoutIfNeeded];
    }];
}


@end

然后在你的xib中将违规约束的类类型更改为此类。

带有滚动视图和键盘的iOS AutoLayout

2 个答案: