如何使用UIButton作为切换按钮？

Question

我正在尝试为表格中的每个单元格创建一个切换按钮.按下时,它将改变图像,再次按下时,它将再次改变图像 - 切换.

在UIButton课堂上,我没有看到一个selected州.

我正在寻找一种方法来创建一个使用UIButton的切换按钮,以便我可以在每次单击时更改状态.

这就是我现在正在rubymotion使用的方式rmq

@fav_button.on(:touch) do |sender|
  puts "pressed fav button for id: " + data[:id] + " and name: " + data[:name]
  #how do I change the state here?
end

Answer 1

您可以轻松创建切换按钮,只需为各个状态设置相应的图像,之后,您可以使用selected属性在这些图像之间切换.

我制作了一个纯粹的Objective-c代码来展示你如何做到这一点,但你也可以在Storyboards ou Xibs中设置图像,请查看:

// First, set the images for normal state and selected state
[button setImage:normalImage forState:UIControlStateNormal];
[button setImage:selectedImage forState:UIControlStateSelected];

// Don't forget to add an action handler to toggle the selected property
[button addTarget:self action:@selector(buttonTouch:withEvent:) forControlEvents:UIControlEventTouchUpInside];

// Now, in your button action handler, you can do something like this:
- (void)buttonTouch:(UIButton *)aButton withEvent:(UIEvent *)event
{
  aButton.selected = !aButton.selected;
}

我希望这可以帮到你.

Answer 2

Swift 4.0 解决方案（使用故事板）

首先，确保在属性检查器中将UIButton类型设置为Custom。

// Reference to UIButton in Storyboard
@IBOutlet weak var toggleButton: UIButton!

override func viewDidLoad() {
    super.viewDidLoad()

    // assumes you have two images in the bundle/project 
    // called normal.png and selected.png.
    let normalImage = UIImage(named: "normal.png")
    let selectedImage = UIImage(named: "selected.png")

    toggleButton.setImage(normalImage, for: .normal)
    toggleButton.setImage(selectedImage, for: .selected)
}

下面的屏幕截图演示toggleButton了 Storyboard 和Touch Up InsideEvent 中的引用，即：用户点击按钮，在didPressButton下面触发。

@IBAction func didPressButton(_ sender: Any) {
    
    // if the button was selected, then deselect it.
    // otherwise if it was not selected, then select it.
    toggleButton.isSelected = !toggleButton.isSelected

    if toggleButton.isSelected {
        print("I am selected.")

    } else {
        print("I am not selected.")
    }
}