ios - Xcode - Swift - 文本的 UILabel 高度扩展

Question

我想让 UILabel 的高度根据其文本扩展。

这是 View Controller 的样子，选中了标签:

这是代码(我尝试了很多不同的类似的东西，但这是我现在拥有的):

import UIKit

class ViewControllerTEST: UIViewController {

@IBOutlet weak var label: UILabel!

override func viewDidLoad() {
    super.viewDidLoad()


    label.frame = CGRectMake(0, 0, CGRectGetWidth(label.bounds), 0)
    label.numberOfLines = 0
    label.lineBreakMode = .ByWordWrapping
    label.text = "This is a really\nlong string"
    label.setNeedsLayout()
    label.sizeToFit()
    label.frame = CGRectMake(0, 0, CGRectGetWidth(label.bounds), CGRectGetHeight(label.bounds))



}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}


/*
// MARK: - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
}
*/

}

而且，正如您在这里看到的，它没有按预期工作:

Answer 1

不要使用框架，使用自动布局。向标签添加顶部、前导和尾随约束(我建议在 Storyboard 中这样做)。只要您的 lines 等于 0(您这样做)，高度就会自动调整。如果你想在代码中添加约束，你的 viewDidLoad 看起来像这样:

override func viewDidLoad() {
    super.viewDidLoad()
    label.text = "This is a really\nlong string"
    label.setTranslatesAutoresizingMaskIntoConstraints(false)
    view.addSubview(label)
    let views = ["label": label]
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-[label]-|", options: nil, metrics: nil, views: views))
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-[label]", options: nil, metrics: nil, views: views))
}