Question

我尝试了sizeWithFont:constrainedToSize:lineBreakMode和sizeToFit，两者都没有返回正确的结果。

属性contentSize应该返回正确的高度，但是在文本视图呈现到屏幕之前它不起作用，我需要在文本视图可见之前计算高度（它确定UITableViewCell的高度。

有没有人找到正确计算UITextView高度的任何其他方法，自定义文本视图等？

修改我应该根据文本视图的内容澄清我想要理想的高度。

Answer 1

IOS 7不再支持属性contentSize。尝试使用此

CGFloat textViewContentHeight = textView.contentSize.height;
textViewContentHeight = ceilf([textView sizeThatFits:textView.frame.size].height + 9);

这解决了我的问题。

Answer 2

以下代码对我有用：

+ (CGFloat)heightOfComment:(NSString *)comment {
    UILabel *label = PrototypeCell.commentLabel;

    // NOTE: The height of the comment should always be at least the height of
    //       one line of text.
    if (comment.length == 0)
        comment = @" ";

    return [comment sizeWithFont:label.font
               constrainedToSize:label.frame.size
                   lineBreakMode:label.lineBreakMode].height;    
}

使其成功的关键是if (comment.length == 0) comment = @" ";。

Answer 3

当涉及sizeToFit：和layouSubview的技术不起作用时，我用这个：

- (CGFloat)measureHeightOfUITextView:(UITextView *)textView
{
    if ([textView respondsToSelector:@selector(snapshotViewAfterScreenUpdates:)])
    {
        // This is the code for iOS 7. contentSize no longer returns the correct value, so
        // we have to calculate it.
        //
        // This is partly borrowed from HPGrowingTextView, but I've replaced the
        // magic fudge factors with the calculated values (having worked out where
        // they came from)

        CGRect frame = textView.bounds;

        // Take account of the padding added around the text.

        UIEdgeInsets textContainerInsets = textView.textContainerInset;
        UIEdgeInsets contentInsets = textView.contentInset;

        CGFloat leftRightPadding = textContainerInsets.left + textContainerInsets.right + textView.textContainer.lineFragmentPadding * 2 + contentInsets.left + contentInsets.right;
        CGFloat topBottomPadding = textContainerInsets.top + textContainerInsets.bottom + contentInsets.top + contentInsets.bottom;

        frame.size.width -= leftRightPadding;
        frame.size.height -= topBottomPadding;

        NSString *textToMeasure = textView.text;
        if ([textToMeasure hasSuffix:@"\n"])
        {
            textToMeasure = [NSString stringWithFormat:@"%@-", textView.text];
        }

        // NSString class method: boundingRectWithSize:options:attributes:context is
        // available only on ios7.0 sdk.

        NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
        [paragraphStyle setLineBreakMode:NSLineBreakByWordWrapping];

        NSDictionary *attributes = @{ NSFontAttributeName: textView.font, NSParagraphStyleAttributeName : paragraphStyle };

        CGRect size = [textToMeasure boundingRectWithSize:CGSizeMake(CGRectGetWidth(frame), MAXFLOAT)
                                                  options:NSStringDrawingUsesLineFragmentOrigin
                                               attributes:attributes
                                                  context:nil];

        CGFloat measuredHeight = ceilf(CGRectGetHeight(size) + topBottomPadding);
        return measuredHeight;
    }
    else
    {
        return textView.contentSize.height;
    }
}

Answer 4

在UITextview布局之前，高度不可用。在iOS 6上，addSubview（例如UIScrollView）给出了布局值（即frame.size.height）。在iOS 7上，这并不总是发生 - 对于sizeToFit，情况也是如此。

我找到了一些解决方案，我更喜欢执行sizeToFit的解决方案，然后在读取（现在已更改）高度之前使用layoutIfNeeded：

...
[scrollView1 addSubview: myTextView];

    [myTextView sizeToFit]; //added
    [myTextView layoutIfNeeded]; //added

CGRect frame = myTextView.frame;
...

这是来自接受的答案here，请参阅说明。我在这里尝试解释的情况是，这对于添加到UITableViewCells而不是UIScrollViews的UITextviews应该是无效的（出于某种原因）。

反正有可靠地计算UITextView的高度吗？

4 个答案: