如果可以避免,我不想使用子视图。我想要一个带有背景图像,文本和图像的UIButton。现在,当我这样做的时候,图像在文本的左边。背景图像、文本和图像都有不同的高亮状态。
当前回答
如果这需要在UIBarButtonItem中完成,则应该使用额外的视图包装 这是可行的
let view = UIView()
let button = UIButton()
button.setTitle("Skip", for: .normal)
button.setImage(#imageLiteral(resourceName:"forward_button"), for: .normal)
button.semanticContentAttribute = .forceRightToLeft
button.sizeToFit()
view.addSubview(button)
view.frame = button.bounds
navigationItem.rightBarButtonItem = UIBarButtonItem(customView: view)
这行不通
let button = UIButton()
button.setTitle("Skip", for: .normal)
button.setImage(#imageLiteral(resourceName:"forward_button"), for: .normal)
button.semanticContentAttribute = .forceRightToLeft
button.sizeToFit()
navigationItem.rightBarButtonItem = UIBarButtonItem(customView: button)
其他回答
把@Piotr的答案变成了一个Swift扩展。请确保在调用此函数之前设置好图像和标题,以便按钮大小适当。
extension UIButton {
/// Makes the ``imageView`` appear just to the right of the ``titleLabel``.
func alignImageRight() {
if let titleLabel = self.titleLabel, imageView = self.imageView {
// Force the label and image to resize.
titleLabel.sizeToFit()
imageView.sizeToFit()
imageView.contentMode = .ScaleAspectFit
// Set the insets so that the title appears to the left and the image appears to the right.
// Make the image appear slightly off the top/bottom edges of the button.
self.titleEdgeInsets = UIEdgeInsets(top: 0, left: -1 * imageView.frame.size.width,
bottom: 0, right: imageView.frame.size.width)
self.imageEdgeInsets = UIEdgeInsets(top: 4, left: titleLabel.frame.size.width,
bottom: 4, right: -1 * titleLabel.frame.size.width)
}
}
}
扩展的方法
使用扩展设置图像右侧自定义偏移
extension UIButton {
func addRightImage(image: UIImage, offset: CGFloat) {
self.setImage(image, for: .normal)
self.imageView?.translatesAutoresizingMaskIntoConstraints = false
self.imageView?.centerYAnchor.constraint(equalTo: self.centerYAnchor, constant: 0.0).isActive = true
self.imageView?.trailingAnchor.constraint(equalTo: self.trailingAnchor, constant: -offset).isActive = true
}
}
约束条件呢?与semanticContentAttribute不同,它们不会改变语义。也许是这样的:
button.rightAnchorconstraint(equalTo: button.rightAnchor).isActive = true
或者在Objective-C中:
[button.imageView.rightAnchor constraintEqualToAnchor:button.rightAnchor].isActive = YES;
警告:未经测试,iOS 9+
Xcode 11.4 Swift 5.2
对于任何试图镜像后退按钮样式的人,像这样的雪佛龙:
import UIKit
class NextBarButton: UIBarButtonItem {
convenience init(target: Any, selector: Selector) {
// Create UIButton
let button = UIButton(frame: .zero)
// Set Title
button.setTitle("Next", for: .normal)
button.setTitleColor(.systemBlue, for: .normal)
button.titleLabel?.font = UIFont.systemFont(ofSize: 17)
// Configure Symbol
let config = UIImage.SymbolConfiguration(pointSize: 19.0, weight: .semibold, scale: .large)
let image = UIImage(systemName: "chevron.right", withConfiguration: config)
button.setImage(image, for: .normal)
// Add Target
button.addTarget(target, action: selector, for: .touchUpInside)
// Put the Image on the right hand side of the button
// Credit to liau-jian-jie for this part
button.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)
button.titleLabel?.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)
button.imageView?.transform = CGAffineTransform(scaleX: -1.0, y: 1.0)
// Customise spacing to match system Back button
button.imageEdgeInsets = UIEdgeInsets(top: 0.0, left: -18.0, bottom: 0.0, right: 0.0)
button.titleEdgeInsets = UIEdgeInsets(top: 0.0, left: -12.0, bottom: 0.0, right: 0.0)
self.init(customView: button)
}
}
实现:
override func viewDidLoad() {
super.viewDidLoad()
let nextButton = NextBarButton(target: self, selector: #selector(nextTapped))
navigationItem.rightBarButtonItem = nextButton
}
@objc func nextTapped() {
// your code
}
我决定不使用标准的按钮图像视图,因为所提出的移动它的解决方案感觉很俗气。这让我获得了想要的美感,并且通过改变约束来重新定位按钮是很直观的:
extension UIButton {
func addRightIcon(image: UIImage) {
let imageView = UIImageView(image: image)
imageView.translatesAutoresizingMaskIntoConstraints = false
addSubview(imageView)
let length = CGFloat(15)
titleEdgeInsets.right += length
NSLayoutConstraint.activate([
imageView.leadingAnchor.constraint(equalTo: self.titleLabel!.trailingAnchor, constant: 10),
imageView.centerYAnchor.constraint(equalTo: self.titleLabel!.centerYAnchor, constant: 0),
imageView.widthAnchor.constraint(equalToConstant: length),
imageView.heightAnchor.constraint(equalToConstant: length)
])
}
}
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