UITextView 内容大小在 iOS7 中不同 [英] UITextView content size different in iOS7

问题描述

我正在使用一个 UITextView，它可以通过点击更多"按钮进行扩展.问题如下:

I am using an UITextView that will be expandable by taping a "more" button. The problem is the following:

在 iOS6 上我使用这个，

On iOS6 I use this,

self.DescriptionTextView.text =  @"loong string";

if(self.DescriptionTextView.contentSize.height>self.DescriptionTextView.frame.size.height) { 
    //set up the more button
}

问题是在 iOS7 上 contentSize.height 返回的值与它在 iOS6 上返回的值不同(远小于).为什么是这样?如何解决?

The problem is that on iOS7 the contentSize.height returns a different value (far smaller) than the value it returns on iOS6. Why is this? How to fix it?

推荐答案

内容大小属性不再像在 iOS 6 上那样工作.根据许多因素，按照其他人的建议使用 sizeToFit 可能会也可能不会起作用.

The content size property no longer works as it did on iOS 6. Using sizeToFit as others suggest may or may not work depending on a number of factors.

它对我不起作用，所以我用它来代替:

It didn't work for me, so I use this instead:

- (CGFloat)measureHeightOfUITextView:(UITextView *)textView
{
    if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_6_1)
    {
        // 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:@"
"])
        {
            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;
    }
}

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