拉伸UIBarButtonItem以适应customView

Question

我为UILabel添加了customView作为UIBarButtonItem。但是，我需要按钮宽度是动态的，以适应更长的标签。目前它只是截断它们。这是我的代码：

let participantCountLabel = UILabel()
participantCountLabel.text = "\(participantCount) participants"
self.toolbarLeftButton.customView = participantCountLabel

我认为可能是因为灵活空间。这需要调整大小吗？

截图：

这是故事板：

Answer 1

也许你可以这样做：

let participantCountLabel = UILabel()
participantCountLabel.text = "\(participantCount) participants"
self.toolbarLeftButton.customView = participantCountLabel
self.toolbarLeftButton.customView.sizeToFit()

Answer 2

尝试这种方式查找文本的宽度和高度，然后设置标签大小

    var participantCountLabel: UILabel=UILabel(frame: CGRectMake(100, 100, 10, 40));
    participantCountLabel.text = "\(participantCount) participants"


    var strText:NSString=participantCountLabel.text!

    let styleLineBreakWordWrap :  NSMutableParagraphStyle=NSMutableParagraphStyle()
    styleLineBreakWordWrap.lineBreakMode=NSLineBreakMode.ByWordWrapping
    styleLineBreakWordWrap.alignment=NSTextAlignment.Left


    var attributes:NSDictionary=[NSFontAttributeName : participantCountLabel.font,
        NSParagraphStyleAttributeName:styleLineBreakWordWrap]

    strText.sizeWithAttributes(attributes);

    var maximumLabelSize : CGSize=CGSizeMake(1000, 100)

    var textRect: CGRect=strText.boundingRectWithSize(maximumLabelSize, options: NSStringDrawingOptions.UsesLineFragmentOrigin, attributes: attributes, context: nil)

    participantCountLabel.frame.size=textRect.size;

    self.toolbarLeftButton.customView = participantCountLabel