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
#import "E_LabelWithPadding.h"
#define padding UIEdgeInsetsMake(2, 0, 2, 0)
#define padding1 UIEdgeInsetsMake(0, 0, 0, 0)
@implementation E_LabelWithPadding
- (void)drawTextInRect:(CGRect)rect {
if (![self.text isEqualToString:@""]) {
[super drawTextInRect:UIEdgeInsetsInsetRect(rect, padding)];
}else {
[super drawTextInRect:UIEdgeInsetsInsetRect(rect, padding1)];
}
}
- (CGSize) intrinsicContentSize {
if (![self.text isEqualToString:@""]) {
CGSize superContentSize = [super intrinsicContentSize];
CGFloat width = superContentSize.width + padding.left + padding.right;
CGFloat height = superContentSize.height + padding.top + padding.bottom;
return CGSizeMake(width, height);
}else {
CGSize superContentSize = [super intrinsicContentSize];
CGFloat width = superContentSize.width + padding1.left + padding1.right;
CGFloat height = superContentSize.height + padding1.top + padding1.bottom;
return CGSizeMake(width, height);
}
}
- (CGSize) sizeThatFits:(CGSize)size {
if (![self.text isEqualToString:@""]) {
CGSize superSizeThatFits = [super sizeThatFits:size];
CGFloat width = superSizeThatFits.width + padding.left + padding.right;
CGFloat height = superSizeThatFits.height + padding.top + padding.bottom;
return CGSizeMake(width, height);
}else {
CGSize superSizeThatFits = [super sizeThatFits:size];
CGFloat width = superSizeThatFits.width + padding1.left + padding1.right;
CGFloat height = superSizeThatFits.height + padding1.top + padding1.bottom;
return CGSizeMake(width, height);
}
}
@end
其他回答
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
}
}
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
}
}
}
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。
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);
}
blyabtroi的asnwer在Swift中转换(不需要子类化)
let style: NSMutableParagraphStyle = NSParagraphStyle.defaultParagraphStyle().mutableCopy() as! NSMutableParagraphStyle
style.alignment = .Justified
style.firstLineHeadIndent = 10.0
style.headIndent = 10.0
style.tailIndent = -10.0
let attrText: NSAttributedString = NSAttributedString(string: title, attributes: [NSParagraphStyleAttributeName:style])
let label: UILabel = UILabel(frame: someFrame)
label.numberOfLines = 0
label.attributedText = attrText
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