iOS 按钮标题颜色不会改变 [英] iOS button title color won't change

问题描述

我正在使用以下代码动态创建一个 UIButton，该代码根据指定的样式创建它.

I'm creating a UIButton dynamically with the following code which creates it as per specified style.

let frame = CGRect(x: 10, y: 6, width: 60, height: 30 )    
let button = UIButton(frame: frame)
button.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
button.backgroundColor = UIColor.whiteColor()
button.addTarget(self, action: "filterByCategory:", forControlEvents: UIControlEvents.TouchUpInside)
self.categoryScrollView.addSubview(button)

使用此按钮，我想在点击时切换样式.以下代码更改背景颜色但不更改标题颜色.知道为什么标题颜色不会改变吗?

With this button, I want to toggle the style when tapped. The following code changes the background color but not the title color. Any idea why title color won't change?

func filterByCategory(sender:UIButton) {

    if sender.backgroundColor != UIColor.blackColor() {
        sender.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Selected)
        sender.backgroundColor = UIColor.blackColor()
    } else {
        sender.setTitleColor(UIColor.blackColor(), forState: UIControlState.Normal)
        sender.backgroundColor = UIColor.whiteColor()
    }

}

推荐答案

因为你的按钮在你触摸之后会变回UIControlState.Normal，所以它变成了.Highlighted, 然后 .Normal

Because your button will turn back to UIControlState.Normal after you touch it, it become .Highlighted, then .Normal

你应该设置sender.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Selected)

到

sender.setTitleColor(UIColor.whiteColor(), forState: UIControlState.Normal)

或者，只需为所有状态设置它，因为您检查了颜色，例如

or, just set it for all the states since u did a check for color like

sender.setTitleColor(UIColor.whiteColor(), forState: [.Normal,.Selected,.Highlighted])

*Edit: 以上不起作用，可以使用 NSAttributedString 代替

* Above doesn't work, can use NSAttributedString instead

if self.loginButton.backgroundColor == UIColor.blackColor() {
            let tittle = NSAttributedString(string: "Login", attributes: [NSForegroundColorAttributeName: UIColor.blackColor()])
            loginButton.setAttributedTitle(tittle, forState: .Normal)
            loginButton.backgroundColor = UIColor.whiteColor()
        } else {
            let tittle = NSAttributedString(string: "Login", attributes: [NSForegroundColorAttributeName: UIColor.whiteColor()])
            loginButton.setAttributedTitle(tittle, forState: .Normal)
            loginButton.backgroundColor = UIColor.blackColor()
        }

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