Iphone 如何为iOS应用程序的UILabel设置左上对齐？

我已经在我的nib文件中添加了一个标签，然后需要对该标签进行左上对齐。因为我在运行时提供文本，所以不确定有多少行。 所以，如果文本只包含一行，则显示为垂直居中对齐。该对齐方式与它前面的相应标签不匹配

例如：

这看起来很奇怪：(

---

有什么方法可以将标签文本正确设置为左上对齐吗？

我将链接到这个内容广泛且评分较高的问题/答案，而不是重新解释：

---

简而言之，答案是否定的，苹果并没有让这变得容易，但可以通过改变帧大小来实现。

这相当容易。使用

verticalAlignment

属性创建一个

UILabel

子容器，并覆盖

textRectForBounds:limitedToNumberOfLines

以返回顶部、中部或底部垂直的正确边界al校准。以下是代码：

SOLabel.h

#import <UIKit/UIKit.h>

typedef enum
{
    VerticalAlignmentTop = 0, // default
    VerticalAlignmentMiddle,
    VerticalAlignmentBottom,
} VerticalAlignment;

@interface SOLabel : UILabel

   @property (nonatomic, readwrite) VerticalAlignment verticalAlignment;

@end

在代码中

label.text = @"some text";
[label sizeToFit];

---

请注意，如果在使用不同数据回收的表格单元格或其他视图中使用该框架，则需要将原始框架存储在某个位置，并在调用sizeToFit之前将其重置。

我也遇到了此问题，但我发现设置UILabel属性和方法的顺序很重要

如果在

label.font=[UIFont fontWithName:@“Helvetica”size:14]；

之前调用

[label size-to-fit]

，则文本不会与顶部对齐，但如果将它们互换，则会对齐

我还注意到，首先设置文本也会产生影响

---

希望这有帮助。

SoLabel works解决方案，谢谢

下面我添加了monotouch版本：

    public class UICustomLabel : UILabel
{
    private UITextVerticalAlignment _textVerticalAlignment;

    public UICustomLabel()
    {
        TextVerticalAlignment = UITextVerticalAlignment.Top;
    }

    public UITextVerticalAlignment TextVerticalAlignment
    {
        get
        {
            return _textVerticalAlignment;
        }
        set
        {
            _textVerticalAlignment = value;
            SetNeedsDisplay();
        }
    }

    public override void DrawText(RectangleF rect)
    {
        var bound = TextRectForBounds(rect, Lines);
        base.DrawText(bound);
    }

    public override RectangleF TextRectForBounds(RectangleF bounds, int numberOfLines)
    {
        var rect = base.TextRectForBounds(bounds, numberOfLines);
        RectangleF resultRect;
        switch (TextVerticalAlignment)
        {
            case UITextVerticalAlignment.Top:
                resultRect = new RectangleF(bounds.X, bounds.Y, rect.Size.Width, rect.Size.Height);
                break;
            case UITextVerticalAlignment.Middle:
                resultRect = new RectangleF(bounds.X,
                                            bounds.Y + (bounds.Size.Height - rect.Size.Height)/2,
                                            rect.Size.Width, rect.Size.Height);
                break;
            case UITextVerticalAlignment.Bottom:
                resultRect = new RectangleF(bounds.X,
                                            bounds.Y + (bounds.Size.Height - rect.Size.Height),
                                            rect.Size.Width, rect.Size.Height);
                break;

            default:
                resultRect = bounds;
                break;
        }

        return resultRect;
    }
}

public enum UITextVerticalAlignment
{
    Top = 0, // default
    Middle,
    Bottom
}

---

SOLabel对我有用

Swift 3和5： 此版本已从原始版本更新，以支持RTL语言：

public class VerticalAlignLabel: UILabel {
    enum VerticalAlignment {
        case top
        case middle
        case bottom
    }

    var verticalAlignment : VerticalAlignment = .top {
        didSet {
            setNeedsDisplay()
        }
    }

    override public func textRect(forBounds bounds: CGRect, limitedToNumberOfLines: Int) -> CGRect {
        let rect = super.textRect(forBounds: bounds, limitedToNumberOfLines: limitedToNumberOfLines)

        if UIView.userInterfaceLayoutDirection(for: .unspecified) == .rightToLeft {
            switch verticalAlignment {
            case .top:
                return CGRect(x: self.bounds.size.width - rect.size.width, y: bounds.origin.y, width: rect.size.width, height: rect.size.height)
            case .middle:
                return CGRect(x: self.bounds.size.width - rect.size.width, y: bounds.origin.y + (bounds.size.height - rect.size.height) / 2, width: rect.size.width, height: rect.size.height)
            case .bottom:
                return CGRect(x: self.bounds.size.width - rect.size.width, y: bounds.origin.y + (bounds.size.height - rect.size.height), width: rect.size.width, height: rect.size.height)
            }
        } else {
            switch verticalAlignment {
            case .top:
                return CGRect(x: bounds.origin.x, y: bounds.origin.y, width: rect.size.width, height: rect.size.height)
            case .middle:
                return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height) / 2, width: rect.size.width, height: rect.size.height)
            case .bottom:
                return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height), width: rect.size.width, height: rect.size.height)
            }
        }
    }

    override public func drawText(in rect: CGRect) {
        let r = self.textRect(forBounds: rect, limitedToNumberOfLines: self.numberOfLines)
        super.drawText(in: r)
    }
}

Swift 1：

---

使用interface builder时，请设置标签的约束条件（确保同时设置高度和宽度）。然后在“大小检查器”中检查标签的高度。您希望标签的读数为>=而不是=。然后在该视图控制器的实现中，将行数设置为0（也可以在IB中完成）然后设置标签[label sizeToFit]；随着文本长度的增加，标签的高度会增加，并将文本保持在左上角。

我找到了解决相同问题的另一种方法。我使用了

UITextView

而不是

UILabel

并切换了

editable（）

函数设置为

false

对于iOS 7，这就是我为自己制作和工作的

@implementation UILabel (VerticalAlign)
- (void)alignTop
{
    CGSize boundingRectSize = CGSizeMake(self.frame.size.width, CGFLOAT_MAX);
    NSDictionary *attributes = @{NSFontAttributeName : self.font};
    CGRect labelSize = [self.text boundingRectWithSize:boundingRectSize options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                              attributes:attributes
                                                 context:nil];
    int numberOfLines= ceil(labelSize.size.height / self.font.lineHeight);

    CGRect newFrame = self.frame;
    newFrame.size.height = numberOfLines * self.font.lineHeight;
    self.frame = newFrame;
}

- (void)alignBottom
{
    CGSize boundingRectSize = CGSizeMake(self.frame.size.width, CGFLOAT_MAX);
    NSDictionary *attributes = @{NSFontAttributeName : self.font};
    CGRect labelSize = [self.text boundingRectWithSize:boundingRectSize options:NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading
                                            attributes:attributes
                                               context:nil];
    int numberOfLines= ceil(labelSize.size.height / self.font.lineHeight);

    int numberOfNewLined = (self.frame.size.height/self.font.lineHeight) - numberOfLines;

    NSMutableString *newLines = [NSMutableString string];
    for(int i=0; i< numberOfNewLined; i++){
        [newLines appendString:@"\n"];
    }
    [newLines appendString:self.text];
    self.text = [newLines mutableCopy];
}

@实现UILabel（垂直对齐）
-（空）对齐顶部
{
CGSize boundingRectSize=CGSizeMake（self.frame.size.width，CGFLOAT_MAX）；
NSDictionary*attributes=@{NSFontAttributeName:self.font}；
CGRect labelSize=[self.text boundingRectWithSize:boundingRectSize选项：NSStringDrawingUserLineFragmentOrigin | NSStringDrawingUserFontLeading
属性：属性
上下文：无]；
int numberOfLines=ceil（labelSize.size.height/self.font.lineHeight）；
CGRect newFrame=self.frame；
newFrame.size.height=numberOfLines*self.font.lineHeight；
self.frame=newFrame；
}
-（空）对齐底部
{
CGSize boundingRectSize=CGSizeMake（self.frame.size.width，CGFLOAT_MAX）；
NSDictionary*attributes=@{NSFontAttributeName:self.font}；
CGRect labelSize=[self.text boundingRectWithSize:boundingRectSize选项：NSStringDrawingUserLineFragmentOrigin | NSStringDrawingUserFontLeading
属性：属性
上下文：无]；
int numberOfLines=ceil（labelSize.size.height/self.font.lineHeight）；
int numberOfNewLined=（self.frame.size.height/self.font.lineHeight）-numberOfLines；
NSMutableString*换行符=[NSMutableString]；
for（int i=0；i

Swift 2.0:：使用UILabel扩展

在空Swift文件中设置常量枚举值

//  AppRef.swift

import UIKit
import Foundation

enum UILabelTextPositions : String {

 case VERTICAL_ALIGNMENT_TOP = "VerticalAlignmentTop"
 case VERTICAL_ALIGNMENT_MIDDLE = "VerticalAlignmentMiddle"
 case VERTICAL_ALIGNMENT_BOTTOM = "VerticalAlignmentBottom"

}

使用UILabel扩展：

创建一个空的Swift类并命名它

//  AppExtensions.swift

import Foundation
import UIKit

    extension UILabel{ 
     func makeLabelTextPosition (sampleLabel :UILabel?, positionIdentifier : String) -> UILabel
     {
      let rect = sampleLabel!.textRectForBounds(bounds, limitedToNumberOfLines: 0)

      switch positionIdentifier
      {
      case "VerticalAlignmentTop":
       sampleLabel!.frame = CGRectMake(bounds.origin.x+5, bounds.origin.y, rect.size.width, rect.size.height)
       break;

      case "VerticalAlignmentMiddle":
       sampleLabel!.frame = CGRectMake(bounds.origin.x+5,bounds.origin.y + (bounds.size.height - rect.size.height) / 2,
        rect.size.width, rect.size.height);
       break;

      case "VerticalAlignmentBottom":
       sampleLabel!.frame = CGRectMake(bounds.origin.x+5, bounds.origin.y + (bounds.size.height - rect.size.height),rect.size.width, rect.size.height);
       break;

      default:
       sampleLabel!.frame = bounds;
       break;
      }
      return sampleLabel!

     }
    }

用法：

myMessageLabel.makeLabelTextPosition(messageLabel, positionIdentifier: UILabelTextPositions.VERTICAL_ALIGNMENT_TOP.rawValue)

---

我在故事板中找到了使用自动布局的解决方案

1） 将行数设置为0，文本对齐设置为左侧

2） 设置高度约束

3） 高度约束应该是相对的-小于或等于

(四)

我得到的结果如下：

---

Swift 3版@totiG的答案

class UIVerticalAlignLabel: UILabel {
    enum VerticalAlignment : Int {
        case VerticalAlignmentTop = 0
        case VerticalAlignmentMiddle = 1
        case VerticalAlignmentBottom = 2
    }

    @IBInspectable var verticalAlignment : VerticalAlignment = .VerticalAlignmentTop {
        didSet {
            setNeedsDisplay()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines: Int) -> CGRect {
        let rect = super.textRect(forBounds: bounds, limitedToNumberOfLines: limitedToNumberOfLines)

        switch(verticalAlignment) {
        case .VerticalAlignmentTop:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y, width: rect.size.width, height: rect.size.height)
        case .VerticalAlignmentMiddle:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height) / 2, width: rect.size.width, height: rect.size.height)
        case .VerticalAlignmentBottom:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height), width: rect.size.width, height: rect.size.height)
        }
    }

    override func drawText(in rect: CGRect) {
        let r = self.textRect(forBounds: rect, limitedToNumberOfLines: self.numberOfLines)
        super.drawText(in: r)
    }
}

---

最简单、最简单的方法是将标签嵌入StackView，并在序列图像板的属性检查器中将StackView的轴设置为水平，与顶部对齐。

如果您需要的是默认从左上角开始的不可编辑文本，您只需使用文本视图而不是标签，然后将其状态设置为不可编辑，像这样：

textview.isEditable = false

比搞乱标签容易多了

---

干杯

在totiG令人敬畏的答案的基础上，我创建了一个IBDesignable类，可以非常轻松地从故事板定制UILabel的垂直对齐方式。只需确保从情节提要标识检查器将UILabel的类设置为“VerticalAlignLabel”。如果垂直对齐没有生效，请转到编辑器->刷新所有视图，这应该会起作用

工作原理： 正确设置UILabel的类后，序列图像板应显示一个接受整数（对齐代码）的输入字段

更新：我添加了对居中标签~Sev的支持

---

输入0作为“顶部对齐”

输入1作为中间对齐

输入2作为“底部对齐”

@IBDesignable类垂直排列
   override func viewWillLayoutSubviews() {
        sampleLabel.sizeToFit()
    }

class UIVerticalAlignLabel: UILabel {
    enum VerticalAlignment : Int {
        case VerticalAlignmentTop = 0
        case VerticalAlignmentMiddle = 1
        case VerticalAlignmentBottom = 2
    }

    @IBInspectable var verticalAlignment : VerticalAlignment = .VerticalAlignmentTop {
        didSet {
            setNeedsDisplay()
        }
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
    }

    override func textRect(forBounds bounds: CGRect, limitedToNumberOfLines: Int) -> CGRect {
        let rect = super.textRect(forBounds: bounds, limitedToNumberOfLines: limitedToNumberOfLines)

        switch(verticalAlignment) {
        case .VerticalAlignmentTop:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y, width: rect.size.width, height: rect.size.height)
        case .VerticalAlignmentMiddle:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height) / 2, width: rect.size.width, height: rect.size.height)
        case .VerticalAlignmentBottom:
            return CGRect(x: bounds.origin.x, y: bounds.origin.y + (bounds.size.height - rect.size.height), width: rect.size.width, height: rect.size.height)
        }
    }

    override func drawText(in rect: CGRect) {
        let r = self.textRect(forBounds: rect, limitedToNumberOfLines: self.numberOfLines)
        super.drawText(in: r)
    }
}

textview.isEditable = false

override func layoutSubViews() {
    super.layoutSubViews()
    // Do other works if needed
    label.sizeToFit()
}

titleLabel.frame = CGRect(x: 20, y: 20, width: 374, height: 291.2)
titleLabel.backgroundColor = UIColor.clear //set a light color to see the frame
titleLabel.textAlignment = .left
titleLabel.lineBreakMode = .byTruncatingTail
titleLabel.numberOfLines = 4
titleLabel.font = UIFont(name: "HelveticaNeue-Bold", size: 35)
titleLabel.text = "Example"
titleLabel.sizeToFit()
self.view.addSubview(titleLabel)

final class TestVC: UIViewController {
    
    lazy var testTextLabel: UITextView = {
        $0.isScrollEnabled = false
        $0.isEditable = false
        
        $0.font = .systemFont(ofSize: 17, weight: .medium)
        $0.textColor = .black
        
        $0.layer.borderWidth = 1
        $0.layer.borderColor = UIColor.black.cgColor
        $0.layer.cornerRadius = 5
        
        return $0
    }(UITextView())
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        view.backgroundColor = .white
        testTextLabel.text = "Your text"
        
        view.addSubview(testTextLabel)
        testTextLabel.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            testTextLabel.topAnchor.constraint(equalTo: testTextLabel.superview!.safeAreaLayoutGuide.topAnchor, constant: 12),
            testTextLabel.leadingAnchor.constraint(equalTo: testTextLabel.superview!.leadingAnchor, constant:  12),
            testTextLabel.widthAnchor.constraint(equalToConstant: 250),
            testTextLabel.heightAnchor.constraint(greaterThanOrEqualToConstant: 70)
        ])
    }
}