ios - 如何将背景图像添加到 UIBarButtonItem

Question

我有以下代码，当点击 textField 时，它会在键盘顶部添加一个 UIToolbar。

如何向其中一个按钮添加背景图片？

我试过...

toolBar.items![1].setBackButtonBackgroundImage(clearButton, forState:.Normal, barMetrics:.Default) 

但它没有用，我收到错误...

Use of unresolved identifier 'imageName'

代码:

func addButtonsToKeyboard(){
    let toolBar = UIToolbar(frame: CGRectMake(0, 0, self.view.frame.size.width, 50))
    toolBar.barStyle = UIBarStyle.Default
    toolBar.tintColor = UIColor.blueColor()
    toolBar.barTintColor = UIColor.grayColor()
    toolBar.items = [
        UIBarButtonItem(title: "Button1", style: UIBarButtonItemStyle.Plain, target: self, action: #selector(someFunction)),
        UIBarButtonItem(title: "Button2", style: UIBarButtonItemStyle.Plain, target: self, action: #selector(someFunction)),
        UIBarButtonItem(title: "Button3", style: UIBarButtonItemStyle.Plain, target: self, action: #selector(someFunction))]

    toolBar.sizeToFit()

    toolBar.items![1].setBackButtonBackgroundImage(myImage, forState:.Normal, barMetrics:.Default)

    myTextField.inputAccessoryView = toolBar
}

顺便说一句 - 图片 myImage 位于 Assets.xcassets 中。

Answer 1

也许您可以尝试创建一个 UIImage 变量，然后将其传递进来以使其更加明确:

var myImage = UIImage(named: "myImage")
toolBar.items![1].setBackButtonBackgroundImage(myImage, forState:.Normal, barMetrics:.Default)