我想设置一个UILabel的左插图/边距,但找不到这样做的方法。标签有一个背景集,所以仅仅改变它的原点是行不通的。这将是理想的插入文本10px左右在左手边。
当前回答
对于多行文本,可以使用NSAttributedString设置左右边距。
NSMutableParagraphStyle *style = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
style.alignment = NSTextAlignmentJustified;
style.firstLineHeadIndent = 10.0f;
style.headIndent = 10.0f;
style.tailIndent = -10.0f;
NSAttributedString *attrText = [[NSAttributedString alloc] initWithString:title attributes:@{ NSParagraphStyleAttributeName : style}];
UILabel * label = [[UILabel alloc] initWithFrame:someFrame];
label.numberOfLines = 0;
label.attributedText = attrText;
以下是Swift 5采用的上述示例:
extension UILabel {
func setMargins(margin: CGFloat = 10) {
if let textString = self.text {
var paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.firstLineHeadIndent = margin
paragraphStyle.headIndent = margin
paragraphStyle.tailIndent = -margin
let attributedString = NSMutableAttributedString(string: textString)
attributedString.addAttribute(.paragraphStyle, value: paragraphStyle, range: NSRange(location: 0, length: attributedString.length))
attributedText = attributedString
}
}
}
其他回答
如果你在ios6 +中使用自动布局,你可以通过在UILabel的子类中调整intrinsicContentSize来实现。
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
self.textAlignment = NSTextAlignmentRight;
}
return self;
}
- (CGSize)intrinsicContentSize
{
CGSize size = [super intrinsicContentSize];
return CGSizeMake(size.width + 10.0, size.height);
}
为UILabel添加填充的最佳方法是子类化UILabel并添加一个edgeInsets属性。然后设置所需的插图,标签将相应地绘制。
OSLabel.h
#import <UIKit/UIKit.h>
@interface OSLabel : UILabel
@property (nonatomic, assign) UIEdgeInsets edgeInsets;
@end
OSLabel.m
#import "OSLabel.h"
@implementation OSLabel
- (id)initWithFrame:(CGRect)frame{
self = [super initWithFrame:frame];
if (self) {
self.edgeInsets = UIEdgeInsetsMake(0, 0, 0, 0);
}
return self;
}
- (void)drawTextInRect:(CGRect)rect {
[super drawTextInRect:UIEdgeInsetsInsetRect(rect, self.edgeInsets)];
}
- (CGSize)intrinsicContentSize
{
CGSize size = [super intrinsicContentSize];
size.width += self.edgeInsets.left + self.edgeInsets.right;
size.height += self.edgeInsets.top + self.edgeInsets.bottom;
return size;
}
@end
对于这样一个简单的情况,子类化有点麻烦。另一种方法是将没有背景设置的UILabel添加到有背景设置的UIView中。将标签的x设置为10,并使外部视图的大小比标签宽20个像素。
在Swift 3中,你可以通过创建UILabel的子类来达到你想要的效果。在这个子类中,你必须添加一个UIEdgeInsets属性,并覆盖drawText(In:)方法,intrinsicContentSize属性(用于自动布局代码)和/或sizeThatFits(_:)方法(用于Springs和Struts代码)。
import UIKit
class PaddingLabel: UILabel {
let padding: UIEdgeInsets
// Create a new PaddingLabel instance programamtically with the desired insets
required init(padding: UIEdgeInsets = UIEdgeInsets(top: 0, left: 10, bottom: 0, right: 10)) {
self.padding = padding
super.init(frame: CGRect.zero)
}
// Create a new PaddingLabel instance programamtically with default insets
override init(frame: CGRect) {
padding = UIEdgeInsets.zero // set desired insets value according to your needs
super.init(frame: frame)
}
// Create a new PaddingLabel instance from Storyboard with default insets
required init?(coder aDecoder: NSCoder) {
padding = UIEdgeInsets.zero // set desired insets value according to your needs
super.init(coder: aDecoder)
}
override func drawText(in rect: CGRect) {
super.drawText(in: UIEdgeInsetsInsetRect(rect, padding))
}
// Override `intrinsicContentSize` property for Auto layout code
override var intrinsicContentSize: CGSize {
let superContentSize = super.intrinsicContentSize
let width = superContentSize.width + padding.left + padding.right
let height = superContentSize.height + padding.top + padding.bottom
return CGSize(width: width, height: height)
}
// Override `sizeThatFits(_:)` method for Springs & Struts code
override func sizeThatFits(_ size: CGSize) -> CGSize {
let superSizeThatFits = super.sizeThatFits(size)
let width = superSizeThatFits.width + padding.left + padding.right
let heigth = superSizeThatFits.height + padding.top + padding.bottom
return CGSize(width: width, height: heigth)
}
}
下面的例子展示了如何在UIViewController中使用PaddingLabel实例:
import UIKit
class ViewController: UIViewController {
@IBOutlet weak var storyboardAutoLayoutLabel: PaddingLabel!
let autoLayoutLabel = PaddingLabel(padding: UIEdgeInsets(top: 20, left: 40, bottom: 20, right: 40))
let springsAndStructsLabel = PaddingLabel(frame: CGRect.zero)
var textToDisplay = "Lorem ipsum dolor sit er elit lamet."
override func viewDidLoad() {
super.viewDidLoad()
// Set autoLayoutLabel
autoLayoutLabel.text = textToDisplay
autoLayoutLabel.backgroundColor = .red
autoLayoutLabel.translatesAutoresizingMaskIntoConstraints = false
view.addSubview(autoLayoutLabel)
autoLayoutLabel.leadingAnchor.constraint(equalTo: view.leadingAnchor, constant: 30).isActive = true
autoLayoutLabel.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
// Set springsAndStructsLabel
springsAndStructsLabel.text = textToDisplay
springsAndStructsLabel.backgroundColor = .green
view.addSubview(springsAndStructsLabel)
springsAndStructsLabel.frame.origin = CGPoint(x: 30, y: 90)
springsAndStructsLabel.sizeToFit()
// Set storyboardAutoLayoutLabel
storyboardAutoLayoutLabel.text = textToDisplay
storyboardAutoLayoutLabel.backgroundColor = .blue
}
// Link this IBAction to a UIButton or a UIBarButtonItem in Storyboard
@IBAction func updateLabelText(_ sender: Any) {
textToDisplay = textToDisplay == "Lorem ipsum dolor sit er elit lamet." ? "Lorem ipsum." : "Lorem ipsum dolor sit er elit lamet."
// autoLayoutLabel
autoLayoutLabel.text = textToDisplay
// springsAndStructsLabel
springsAndStructsLabel.text = textToDisplay
springsAndStructsLabel.sizeToFit()
// storyboardAutoLayoutLabel
storyboardAutoLayoutLabel.text = textToDisplay
}
}
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
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