ios - TextView文本未正确显示

Question

我使用自动布局。我有一个包含其他 View 的 TextView。当键盘出现时，部分 TextView 隐藏在键盘后面。因此，我通过降低其底部约束(及其父 View 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，TextView 的文本只有一半是可见的。但是当我点击它时，它会显示整个文本。

正常情况下的样子:

键盘出现时的样子:

键盘消失后的样子:

现在，如果我点击 TextView，它看起来与第一张图片相同。即完整的文本是可见的:

代码: self.messageView 是 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];
}

注意:只有当 TextView 的 contentOffset 是 (0 ,0).即用户没有滚动它或滚动回顶部。如果用户滚动它并且 contentOffset 不是 (0,0) 那么它工作正常。

Answer 1

我只是取消选中 Storyboard中 TextView 的滚动启用属性，它不再出现该问题。