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[英]How to set an action for barbutton item programatically objective-c
[英]Programattically set barbutton “ System Item”
我想在导航 controller 的 rightbarbuttonitem 上设置共享按钮。 我不想添加自定义图像,我想使用 Xcode 提供的共享按钮图像。这就是我在 storyboard 中的做法。 我设置Style ,并将System_Item设置为Action 。
现在的问题是,如果我以编程方式创建 barbuttonitem,如何以编程方式设置System_Item ?
let shareButton = UIBarButtonItem(title: "",
style: .plain,
target: self,
action: #selector(shareAction(sender:)))
shareButton.tintColor = AppColor.barButtonColor
navigationItem.rightBarButtonItem = shareButton
您可以创建一个扩展来执行此操作->
public extension UIViewController {
func setRightBarButtonItem(tintColor: UIColor = AppColor.barButtonColor) {
let button = UIButton(type: .system)
button.tintColor = tintColor
button.setImage(UIImage(.action), for: .normal) // <-- Set system icon to button
button.translatesAutoresizingMaskIntoConstraints = false
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(tap))
button.addGestureRecognizer(tapGesture)
navigationItem.rightBarButtonItem = UIBarButtonItem(customView: button)
}
@objc func tap() {
// Do stuff
}
}
然后在你的 ViewController
override func viewDidLoad() {
super.viewDidLoad()
setRightBarButtonItem()
// OR
setRightBarButtonItem(tintColor: .blue)
}
UIImage 扩展使用没有版本控制的系统图标
extension UIImage {
public convenience init?(_ systemItem: UIBarButtonItem.SystemItem) {
guard let sysImage = UIImage.imageFrom(systemItem: systemItem)?.cgImage else {
return nil
}
self.init(cgImage: sysImage)
}
private class func imageFrom(systemItem: UIBarButtonItem.SystemItem) -> UIImage? {
let sysBarButtonItem = UIBarButtonItem(barButtonSystemItem: systemItem, target: nil, action: nil)
let toolBar = UIToolbar()
toolBar.setItems([sysBarButtonItem], animated: false)
toolBar.snapshotView(afterScreenUpdates: true)
if let buttonView = sysBarButtonItem.value(forKey: "view") as? UIView{
for subView in buttonView.subviews where subView is UIButton {
let button = subView as! UIButton
let image = button.imageView!.image!
return image
}
}
return nil
}
}
您需要使用 UIBarButtonSystemItemAction 选项直接获取共享操作
let share = UIBarButtonItem(barButtonSystemItem: .action, target: self, action: #selector(shareAction(sender:)))
shareButton.tintColor = AppColor.barButtonColor
navigationItem.rightBarButtonItem = share
并像处理动作一样
@objc func shareAction(sender: UIBarButtonItem) {
}
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