和@IBDesignable，使其与接口生成器一起工作

斯威夫特4

//
//  PaddedLabel.swift
//  TrainCentric
//
//  Created by Arsonik
//  https://stackoverflow.com/a/33244365/337934
//

import UIKit

@IBDesignable
class PaddedLabel: UILabel {

    @IBInspectable var inset:CGSize = CGSize(width: 0, height: 0)

    var padding: UIEdgeInsets {
        var hasText:Bool = false
        if let t = self.text?.count, t > 0 {
            hasText = true
        }
        else if let t = attributedText?.length, t > 0 {
            hasText = true
        }

        return hasText ? UIEdgeInsets(top: inset.height, left: inset.width, bottom: inset.height, right: inset.width) : UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    }

    override func drawText(in rect: CGRect) {
        super.drawText(in: rect.inset(by: padding))
    }

    override var intrinsicContentSize: CGSize {
        let superContentSize = super.intrinsicContentSize
        let p = padding
        let width = superContentSize.width + p.left + p.right
        let heigth = superContentSize.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }

    override func sizeThatFits(_ size: CGSize) -> CGSize {
        let superSizeThatFits = super.sizeThatFits(size)
        let p = padding
        let width = superSizeThatFits.width + p.left + p.right
        let heigth = superSizeThatFits.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }
}

斯威夫特2

@IBDesignable
class PaddedLabel: UILabel {

    @IBInspectable var inset:CGSize = CGSize(width: 0, height: 0)

    var padding: UIEdgeInsets {
        var hasText:Bool = false
        if let t = text?.length where t > 0 {
            hasText = true
        }
        else if let t = attributedText?.length where t > 0 {
            hasText = true
        }

        return hasText ? UIEdgeInsets(top: inset.height, left: inset.width, bottom: inset.height, right: inset.width) : UIEdgeInsets(top: 0, left: 0, bottom: 0, right: 0)
    }

    override func drawTextInRect(rect: CGRect) {
        super.drawTextInRect(UIEdgeInsetsInsetRect(rect, padding))
    }

    override func intrinsicContentSize() -> CGSize {
        let superContentSize = super.intrinsicContentSize()
        let p = padding
        let width = superContentSize.width + p.left + p.right
        let heigth = superContentSize.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }

    override func sizeThatFits(size: CGSize) -> CGSize {
        let superSizeThatFits = super.sizeThatFits(size)
        let p = padding
        let width = superSizeThatFits.width + p.left + p.right
        let heigth = superSizeThatFits.height + p.top + p.bottom
        return CGSize(width: width, height: heigth)
    }
}

我通过子类化UILabel和重写drawTextInRect来解决这个问题:

- (void)drawTextInRect:(CGRect)rect {
    UIEdgeInsets insets = {0, 5, 0, 5};
    [super drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];
}

斯威夫特3.1:

override func drawText(in rect: CGRect) {
    let insets = UIEdgeInsets.init(top: 0, left: 5, bottom: 0, right: 5)
    super.drawText(in: UIEdgeInsetsInsetRect(rect, insets))
}

斯威夫特4.2.1:准备

override func drawText(in rect: CGRect) {
    let insets = UIEdgeInsets(top: 0, left: 5, bottom: 0, right: 5)
    super.drawText(in: rect.inset(by: insets))
}

你可能已经猜到了，这是对tc的改编。的答案。它有两个优点:

没有必要通过发送sizeToFit消息来触发它 它只保留标签框架——如果你的标签有背景，而你不想让它缩小，这很方便

没有子类和所有的爵士。我动态地做了这个:

[cell.textLabel setTranslatesAutoresizingMaskIntoConstraints:NO];
[cell.textLabel constraintTrailingEqualTo:cell.contentView constant:-100];

约束部分只是一个简单的代码糖纸(我们有相同的方法从上/下/左/右添加填充)..如果我在这里得到足够的爱，我将开放整个包装:

- (id)constraintTrailingEqualTo:(UIView *)toView constant:(CGFloat)constant
{
    NSLayoutConstraint *cn = [NSLayoutConstraint constraintWithItem:self
                                                          attribute:NSLayoutAttributeTrailing
                                                          relatedBy:NSLayoutRelationEqual
                                                             toItem:toView
                                                          attribute:NSLayoutAttributeTrailing
                                                         multiplier:1 constant:constant];

    [toView addConstraint:cn];
    return self;
}

(注意，我是在

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath: (NSIndexPath *)indexPath;

你可能需要调用[self setNeedsLayout];这取决于你的语境。

不要编码，Xcode !

比起使用UILabel来解决这个问题，我建议你去看看UIButton。它提供了开箱即用的功能，可以在大小检查器中设置内容插入(上、左、下、右)。设置所需的边距，然后在Xcode中禁用按钮，完成。

我认为UILabel类没有设置边距的方法。为什么不把标签的位置设置在需要的位置?

见下面的代码:

UILabel *label = [[UILabel alloc] init];
label.text = @"This is label";
label.frame = CGRectMake(0,0,100,100);

如果来自接口构建器，则按以下方式定位Label:

yourLabel.frame = CGRectMake(0,0,100,100);

如果你不想使用一个额外的父视图来设置背景，你可以子类化UILabel并重写textRectForBounds: limitedtonumberolines:。我会添加一个textEdgeInsets属性或类似的，然后做

- (CGRect)textRectForBounds:(CGRect)bounds limitedToNumberOfLines:(NSInteger)numberOfLines
{
  return [super textRectForBounds:UIEdgeInsetsInsetRect(bounds,textEdgeInsets) limitedToNumberOfLines:numberOfLines];
}

为了健壮性，你可能还想在setTextEdgeInsets:中调用[self setNeedsDisplay]，但我通常不这么做。