boundingRectWithSize不复制UITextView

Question

我在项目中的要求是UITextView应该根据内容的内容减小字体大小UITextView.所以我想用估计文本的大小boundingRectWithSize.

问题是我得到的字体有点太大,文本的某些部分会被剪裁.

我的职责:

 -(BOOL)updateTextViewFontSizeForText:(NSString*)text{

    float fontSize = self.maximumFontSizeInPoints;

    self.font = [self.font fontWithSize:fontSize];

    CGSize tallerSize ;
    CGSize stringSize ;


    do
    {
        if (fontSize <= self.minimumFontSizeInPoints) // it just won't fit
            return NO;

        fontSize -= 1.0;
        self.font = [self.font fontWithSize:fontSize];

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

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



        tallerSize = CGSizeMake(self.frame.size.width,self.frame.size.height-16);// the 16 is given because uitextview adds some offset
        stringSize = [text boundingRectWithSize:CGSizeMake(self.contentSize.width,CGFLOAT_MAX) options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attributes context:nil].size;
    }while(stringSize.height >= tallerSize.height);


    if ([self.onTextChangDelegate respondsToSelector:@selector(onTextChangDelegate)]) {

        [self.onTextChangDelegate onTextChanged:text];
    }

    return YES;
}

Answer 1

我试图做同样的事情时遇到了同样的问题.

问题是UITextViewruning的换行与boundingRectWithSize相比如何.您可以在此处阅读更多详细信息:https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/TextLayout/Concepts/CalcTextLayout.html

但你实际上可以计算出确切的大小!基本上有两个属性UITextView,您需要考虑这些属性才能获得正确的大小估计值.第一个是textContainer.lineFragmentPadding,第二个是textContainerInset.

首先,textContainer.lineFragmentPadding您可能已经注意到您的大小调整通常总是关闭10px,这是因为系统默认值为5px.当您计算估计的大小时,您需要从您检查的大小中减去此值,并在获得最终值时将其重新添加.

第二,textContainerInset.这是UIEdgeInset您需要添加回最终计算值以匹配系统的情况.

这是基于我如何解决问题的代码:

- (CGSize)sizeThatFits:(CGSize)size
    CGFloat lineFragmentPaddings = self.textContainer.lineFragmentPadding * 2;
    CGFloat horzPadding = self.textContainerInset.left + self.textContainerInset.right + lineFragmentPaddings;
    CGFloat vertPadding = self.textContainerInset.top + self.textContainerInset.bottom;

    size.width -= horzPadding;
    CGRect boundingRect = [attributedText boundingRectWithSize:size options:NSStringDrawingUsesLineFragmentOrigin context:nil];
    size = boundingRect.size;
    // I found through debugging that adding 0.25 rounded
    // matches sizeThatFits: identically. Not sure why…
    size.width += horzPadding + 0.25;
    size.height += vertPadding + 0.25;
    size = CGSizeRound(size);

    return size;
}

请注意,CGSizeRound仅仅是一个自定义函数,我写的是圆整width并height的CGSize到最近0.5.

为了便于比较,如果您创建第二个UITextView,并确保textContainer.lineFragmentPadding和textContainerInset是相同的,你应该看到的值几乎相同的最近0.5.

关于计算正确的pointSize的问题,这是一些伪代码:

CGFloat pointSize = 64;
CGFloat minPointSize = 32;
CGFloat decrementor = 4;
CGFloat padding = self.textContainerInset.left + self.textContainerInset.right + lineFragmentPaddings;
CGFloat actualWidth = self.maxTextViewSize.width - padding * 2;
CGRect boundingRect = CGRectZero;
BOOL isValidPointSize = NO;
do {
    if (pointSize < minPointSize) {
        pointSize = minPointSize;
        boundingRect.size.height = self.maxTextViewSize.height;
        isValidPointSize = YES;
    } else {
        NSDictionary *defaultAttributes = [self.customTextStorage defaultAttributesForPointSize:pointSize];
        NSAttributedString *attrString = [[NSAttributedString alloc] initWithString:string attributes:defaultAttributes];

        boundingRect = [attrString boundingRectWithSize:CGSizeMake(actualWidth, 1024) options:NSStringDrawingUsesLineFragmentOrigin context:nil];
        // is the height to big?
        if (boundingRect.size.height > self.maxTextViewSize.height) {
            // reduce the point size for next iteration of loop
            pointSize -= decrementor;
        }
        // passes height test
        else {
            isValidPointSize = YES;
        }
    }
} while (!isValidPointSize);

return pointSize;

同样,以上是基于我的实现的伪代码(并不意味着只是替换你所拥有的).希望这可以帮助!

Answer 2

尝试这样

UITextView *textViewObj;//initialise textview.  

textViewObj.autoresizesSubviews = NO;
textViewObj.autoresizingMask = UIViewAutoresizingNone;