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
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
}
}
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
}
}
#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
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。
如果以编程方式创建标签，则可以使用sizeThatFits方法计算填充。如果使用多行，文本将以最大宽度值换行。
let text = UILabel()
let padding = 10
text.layer.cornerRadius = 5
text.layer.masksToBounds = true
text.text = "Hello"
text.font = UIFont(name: text.font.fontName, size: 18)
text.textAlignment = NSTextAlignment.center
text.numberOfLines = 1
let maxSize = CGSize(width: 100, height: 100)
var size = text.sizeThatFits(maxSize)
size.width = size.width + padding * 2
size.height = size.height + padding * 2
text.frame = CGRect(origin: CGPoint(x: 0, y: 0), size: size)
Swift 4版的blyabtroi解决方案
let leadingMargin: CGFloat = 10
let trailingMargin: CGFloat = 10
let style = NSMutableParagraphStyle()
style.alignment = .justified
style.firstLineHeadIndent = leadingMargin
style.headIndent = leadingMargin
style.tailIndent = trailingMargin
label.attributedText = NSAttributedString(string: "Label with margins",
attributes: [NSAttributedStringKey.paragraphStyle: style])
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