使用 uitextview 在 ios 版本 6 和 7 中显示 html 文本

Question

我正在使用 web 服务在我的 ios 应用程序中显示内容。

在网络上，数据使用富编辑文本框存储。

所以作为响应，我正在显示 HTML 文本。

现在我使用 UITextView 在我的应用程序中显示 html 文本。

[_txt_desc setValue:@"html text here" forKey:@"contentToHTMLString"];
    [_txt_desc setFont:[UIFont fontWithName:custom_font_name size:is_ipad?18:14]];
    _txt_desc.editable = NO;
    _txt_desc.scrollEnabled = NO;

现在我需要计算 uitextview 的大小，以便我可以重新定位 UItextview 下方的视图。

为了计算 uitextview 的高度，我使用了下面描述的函数。

+ (CGFloat)measureHeightOfUITextView:(UITextView *)textView withHtmlString:(NSString *)htmlString
{
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)
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    [paragraphStyle setLineBreakMode:NSLineBreakByWordWrapping];
    CGFloat measuredHeight=0;
    if ([htmlString length]>0) {
        textView.translatesAutoresizingMaskIntoConstraints = NO;
//            NSAttributedString *attributedString = [[NSAttributedString alloc] initWithData:   [htmlString dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType ,NSParagraphStyleAttributeName : paragraphStyle,NSFontAttributeName:textView.font} documentAttributes:nil error:nil];
        NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithData:[htmlString dataUsingEncoding:NSUnicodeStringEncoding] options:@{ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType ,NSFontAttributeName:[UIFont fontWithName:custom_font_name size:is_ipad?16:14]} documentAttributes:nil error:nil];

        textView.attributedText = attributedString;

        // Take account of the padding added around the text.
    }
    CGRect frame = textView.bounds;
    NSLog(@"content size %@",NSStringFromCGSize(textView.frame.size));
    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.


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

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

    measuredHeight = ceilf(CGRectGetHeight(size) + topBottomPadding);


    return measuredHeight;
}
else
{
    CGSize constraintSize = CGSizeMake(textView.frame.size.width, MAXFLOAT);
    CGSize labelSize = [textView.text sizeWithFont:textView.font constrainedToSize:constraintSize lineBreakMode:NSLineBreakByWordWrapping];
    int occurance = 0;
    occurance=(int)[[htmlString componentsSeparatedByString:@"<p>"] count];
    float height=0;
    if(occurance>1){
        height =occurance*(is_ipad?20:10);
    }
    occurance = (int)[[htmlString componentsSeparatedByString:@"<br/>"] count];
    if(occurance>1){
        height +=occurance*(is_ipad?20:10);
    }
    occurance = (int)[[htmlString componentsSeparatedByString:@"<br>"] count];
    if(occurance>1){
        height +=occurance*(is_ipad?20:10);
    }
    occurance = (int)[[htmlString componentsSeparatedByString:@"<h2>"] count];
    if(occurance>1){
        height +=occurance*(is_ipad?30:20);
    }
    occurance = (int)[[htmlString componentsSeparatedByString:@"<h3>"] count];
    if(occurance>1){
        height +=occurance*(is_ipad?30:20);
    }

    return labelSize.height+(is_ipad?30:20)+textView.font.pointSize+height;
}
}

现在它正在正确返回高度。

但现在的问题是，当它在低于 ios 7.0 的版本中显示文本时，它的文本大小是根据以编程方式给出的，而在 ios 7 中它不显示给定字体大小的文本。

那么在ios 7中字体大小显示的解决方案是什么。

提前致谢 博斯卡尼亚

Answer 1

很简单。我希望这能帮助那些正在努力解决 Uitextview 动态高度问题的人。

[_txt_desc setValue:@"html text here" forKey:@"contentToHTMLString"];
[_txt_desc sizeThatFits:CGSizeMake(_txt_desc.frame.size.width,FLT_MAX)].height;

谢谢 bskania。