Question

我的代码出错了.. 它应该做什么：当用户点击按钮时，图像变为已选中，再次点击，更改为未选中。

我得到错误：AnyObject没有成员名称'setImage ...

 @IBAction func tick(sender: AnyObject) {
    if let image = UIImage(named:"Unchecked") {
        sender.setImage(UIImage(named:"Checked.png"), forControlState: .Normal)
    }
    if let image = UIImage(named:"Checked") {
        sender.setImage( UIImage(named:"Unchecked.png"), forControlState: .Normal)
    }
}

Answer 1

您必须明确告诉compiler sender是UIButton而不是AnyObject类型。

    @IBAction func tick(sender: AnyObject) {
     if let button = sender as! UIbutton {
        if let image = UIImage(named:"Unchecked") {
            button.setImage(UIImage(named:"Checked.png"), forControlState: .Normal)
        }
        if let image = UIImage(named:"Checked") {
            button.setImage( UIImage(named:"Unchecked.png"), forControlState: .Normal)
        }
      } 
    }

Answer 2

您只需将（sender：AnyObject）更改为（sender：UIButton）如下

@IBAction func tick(sender: UIButton) {
    if let image = UIImage(named:"Unchecked") {
        sender.setImage(UIImage(named:"Checked.png"), forControlState: .Normal)
    }
    if let image = UIImage(named:"Checked") {
        sender.setImage( UIImage(named:"Unchecked.png"), forControlState: .Normal)
    }
}

Answer 3

你可以这样做：

var checked = false

@IBAction func tick(sender: UIButton) {

    if checked {
        sender.setImage( UIImage(named:"Unchecked.png"), forState: .Normal)
        checked = false
    } else {
        sender.setImage(UIImage(named:"Checked.png"), forState: .Normal)
        checked = true
    }
}

通过点击改变UIButton的图像 - Swift

3 个答案: