隐藏键盘时视图未正确布局

Question

我有TextView。当键盘出现时，TextView的一部分隐藏在键盘后面。因此，我通过减少其底部约束（其superview的底部）来降低其高度，以便用户可以滚动并查看整个文本。

但问题是当键盘消失时它没有将TextView的高度调整为原始高度。但是当我点击它时，它会显示与第一张图像相同的全文。

看起来如何：

键盘出现时的外观：

键盘消失时的外观：

现在，如果我点按TextView，它看起来与第一张图片相同。即调整大小以适当大小：

代码： self.messageView为TextView。

// Called when keyboard is going to be displayed
- (void)keyboardWillShow:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];

    // get animation info from userInfo
    NSTimeInterval animationDuration;
    CGRect keyboardFrame;
    [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] getValue:&keyboardFrame];

    // Save constant to set back later
    self.bottomConstant = self.noticeMessageBottom.constant;

    // Change bottom space constraint's constant
    self.noticeMessageBottom.constant = keyboardFrame.size.height + 8.0f;

    [UIView animateWithDuration:animationDuration delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{

        [self.messageView setNeedsLayout];
        [self.messageView layoutIfNeeded];

        [self.view setNeedsLayout];
        [self.view layoutIfNeeded];
    } completion:nil];

    [self.messageView flashScrollIndicators];
}

// Called when keyboard is going to be hidden
- (void)keyboardWillHide:(NSNotification*)aNotification
{
    NSDictionary* info = [aNotification userInfo];

    // get animation info from userInfo
    NSTimeInterval animationDuration;
    CGRect keyboardFrame;
    [[info objectForKey:UIKeyboardAnimationDurationUserInfoKey] getValue:&animationDuration];
    [[info objectForKey:UIKeyboardFrameBeginUserInfoKey] getValue:&keyboardFrame];

    // Reset contentOffset
    self.messageView.contentOffset = CGPointZero;

    // Change bottom space constraint's constant
    self.noticeMessageBottom.constant = self.bottomConstant;

    [UIView animateWithDuration:animationDuration delay:0.0 options:UIViewAnimationOptionCurveEaseOut animations:^{

        [self.messageView setNeedsLayout];
        [self.messageView layoutIfNeeded];

        [self.view setNeedsLayout];
        [self.view layoutIfNeeded];
    } completion:nil];
}

更新：我将背景颜色设置为TextView，并看到高度已正确更改，但部分文字不可见。当我点击它时它变得可见。

注意： 仅当TextView的{​​{1}}为contentOffset时才会发生这种情况。即用户尚未滚动它。如果用户滚动它并且(0,0)不是contentOffset，那么它可以正常工作。

Answer 1

我只是在故事板中取消选中TextView的滚动启用属性，而不再提供该问题。