点击时如何反复更改按钮？

Question

使用 Swift，我该如何制作：

带有文字 "start" 的按钮，点击后会变为 "pause"，反之亦然？不只是一次，而是可以无限次做？（例如在秒表应用中）
点击时在 2 个图像之间切换的自定义图像按钮，也可以无限完成（点击和更改）？

Answer 1

在按钮的@IBAction 中（假设您使用的是故事板），您可以将按钮的标题或图像更改为您想要的。您还可以检查标题或图像，并根据您所拥有的执行操作。

@IBAction func pressbutton(sender: UIButton) {
    switch sender.titleLabel?.text {
        case "Play":
        play()
        case "Pause":
        pause()
    default:
        other()
    }
    sender.titleLabel?.text = "Whatever you want"
}

或者图像（假设你有一个 images 数组存储图像，你应该这样做）：

@IBAction func pressbutton(sender: UIButton) {
    switch sender.imageView!.image! {
        case images[0]:
            play()
        case images[1]:
            pause()
    default:
        other()
    }
    sender.imageView?.image = UIImage(...)
}

Answer 2

在故事板中，将 Default 状态标题设置为 "Start"，将 Selected 状态标题设置为 "Pause"

或者，如果您在代码中这样做：

startPauseButton.setTitle("Start", forState: .Normal)
startPauseButton.setTitle("Pause", forState: .Selected)

在您的 IBAction func 中，在 true 和 false

之间切换 button.selected 属性

@IBAction func toggleStopwatch(button:UIButton) {
    if button.selected {
        // Pause the stopwatch
    } else {
        // Start the stopwatch
    }
    button.selected = !button.selected
}

您还可以为不同的状态设置不同的图像：默认、突出显示、已选择 , 已禁用

Answer 3

试试这个....

@IBAction func btnStopWatch(sender: UIButton) {
        if btnStopWatch.selected == true  {
            btnStopWatch.setTitle("stop", forState: UIControlState.Normal)
            btnStopWatch.setImage(stopImage, forState: UIControlState.Normal)
            btnStopWatch.selected = false
        } else {
            btnStopWatch.setTitle("start", forState: UIControlState.Normal)
            btnStopWatch.setImage(startImage, forState: UIControlState.Normal)
            btnStopWatch.selected = true
        }
    }

Answer 4

步骤 1： 创建布尔变量

var isPlaying:Bool = false

第 2 步： 使用此 IBAction 方法连接您的按钮：

@IBAction func btnStartStop(sender: UIButton) {
    if isPlaying{

        isPlaying = false
        sender.setTitle("Pause", forState: UIControlState.Normal)
        sender.setImage(pauseImage, forState: .Normal)
        //Pause Stopwatch
    }
    else{

        isPlaying = true
        sender.setTitle("Play", forState: UIControlState.Normal)
        sender.setImage(playImage, forState: .Normal)
      //Play Stopwatch
    }
  }

Answer 5

#1。切换 `UIButton` 标题

对于Swift3，UIButton有一个方法叫做setTitle(_:for:)。 setTitle(_:for:) 有以下声明：

func setTitle(_ title: String?, for state: UIControlState)

Sets the title to use for the specified state.

以下 Playground 代码展示了如何使用 setTitle(_:for:) 来根据按钮的状态切换按钮的标题：

import PlaygroundSupport
import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = UIColor.white

        let button = UIButton(type: UIButtonType.system)
        button.addTarget(self, action: #selector(toggle(sender:)), for: UIControlEvents.touchUpInside)

        // Set button's states
        button.setTitle("Start", for: UIControlState.normal)
        button.setTitle("Pause", for: UIControlState.selected)

        // set layout
        view.addSubview(button)
        button.translatesAutoresizingMaskIntoConstraints = false
        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint])
    }

    /// trigger action when button is tapped
    func toggle(sender: UIButton) {
        sender.isSelected = !sender.isSelected
        print("Button state: \(sender.isSelected)")
    }

}

let vc = ViewController()
PlaygroundPage.current.liveView = vc

使用 View > Assistant Editor > Show Assistant Editor[=] 在 Playground Assistant Editor 中预览视图控制器

#2。切换 `UIButton` 图片

UIButton 有一个名为 setImage(_:for:) 的方法。 setImage(_:for:) 有以下声明：

func setImage(_ image: UIImage?, for state: UIControlState)

Sets the image to use for the specified state.

以下 Playground 代码展示了如何使用 setImage(_:for:) 来根据按钮的状态切换按钮的标题：

import PlaygroundSupport
import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        view.backgroundColor = UIColor.white

        let button = UIButton()
        button.addTarget(self, action: #selector(toggle(sender:)), for: UIControlEvents.touchUpInside)

        // Set button's states
        button.setImage(UIImage(named: "on.png"), for: UIControlState.normal)
        button.setImage(UIImage(named: "off.png"), for: UIControlState.selected)

        // set layout
        view.addSubview(button)
        button.translatesAutoresizingMaskIntoConstraints = false
        let horizontalConstraint = button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        let verticalConstraint = button.centerYAnchor.constraint(equalTo: view.centerYAnchor)
        let heightConstraint = button.heightAnchor.constraint(equalToConstant: 100)
        let widthConstraint = button.widthAnchor.constraint(equalToConstant: 100)
        NSLayoutConstraint.activate([horizontalConstraint, verticalConstraint, heightConstraint, widthConstraint])
    }

    /// trigger action when button is tapped
    func toggle(sender: UIButton) {
        sender.isSelected = !sender.isSelected
        print("Button state: \(sender.isSelected)")
    }

}

let vc = ViewController()
PlaygroundPage.current.liveView = vc

使用 View > Assistant Editor > Show Assistant Editor[=] 在 Playground Assistant Editor 中预览视图控制器

点击时如何反复更改按钮？

How to change button repeatedly when tapped?

xcode

button

ios

swift

#1。切换 `UIButton` 标题

#2。切换 `UIButton` 图片

点击时如何反复更改按钮？

How to change button repeatedly when tapped?

xcode

button

ios

swift

#1。切换 UIButton 标题

#2。切换 UIButton 图片

#1。切换 `UIButton` 标题

#2。切换 `UIButton` 图片