在我的应用程序中,我按下按钮,它会使用iOS默认按钮动画更改背景颜色等号码。按钮的默认行为就像数字只能在区间[x,x + 1]或[x-1,x]中,其中x是初始值。但是如果快速按下按钮,则相同的数字会迅速增加或迅速减小。
func likeButtonAction(sender:UIButton!) {
var oldValue = sender.titleLabel?.text?.toInt()
println("oldvalue \(oldValue)")
if sender.selected {
//upvote
sender.setTitle(String(oldValue! + 1), forState: UIControlState.Normal|UIControlState.Selected)
println("inc \(oldValue! + 1)")
} else {
//downvote
sender.setTitle(String(oldValue! - 1), forState: UIControlState.Normal|UIControlState.Selected)
println("dec \(oldValue! - 1)")
}
}
EDIT1: 当快速按下输出时:
oldvalue Optional(3)
inc 4
oldvalue Optional(4)
dec 3
oldvalue Optional(3)
inc 4
oldvalue Optional(4)
dec 3
oldvalue Optional(4)
inc 5
oldvalue Optional(5)
dec 4
oldvalue Optional(5)
inc 6
oldvalue Optional(6)
dec 5
oldvalue Optional(6)
inc 7
oldvalue Optional(7)
dec 6
oldvalue Optional(7)
inc 8
oldvalue Optional(8)
dec 7
oldvalue Optional(8)
inc 9
oldvalue Optional(9)
dec 8
oldvalue Optional(8)
inc 9
EDIT2: 解: 这工作正常,但我不知道为什么。解释将不胜感激
func likeButtonAction(sender:UIButton!)
if sender.selected {
//upvote
sender.setTitle(String((sender.titleLabel?.text?.toInt())! + 1), forState: UIControlState.Normal|UIControlState.Selected)
} else {
//downvote
sender.setTitle(String((sender.titleLabel?.text?.toInt())! - 1), forState: UIControlState.Normal|UIControlState.Selected)
}
}
答案 0 :(得分:1)
自
以来这不起作用 if sender.backgroundImageForState(UIControlState.Normal) == UIImage(named: "like.png")
总是假的..
UIImage(名称:" like.png")
将创建新的UIImage实例。
您可以指定"标记"任何视图(在这种情况下是一个UIButton)来处理这种情况。
答案 1 :(得分:1)
我的建议是将.Normal和.Selected的按钮状态分别设置为“like.png”和“likes.png”。然后你的代码就像:
一样简单func likeButtonAction(sender:UIButton!) {
if sender.selected {
//upvote
sender.setTitle(String(oldValue! + 1), forState: UIControlState.Normal)
sender.setTitleColor(MyStyle.ThemeSecondColor, forState: UIControlState.Normal)
} else {
//downvote
sender.setTitle(String(oldValue! - 1), forState: UIControlState.Normal)
sender.setTitleColor(MyStyle.ThemeColor, forState: UIControlState.Normal)
}
//Quickly flip the button state to the opposite of what it was
sender.selected = !sender.selected
}
编辑:
嗯,您可以实现一个变量来保存“count”并先设置它,然后用该设置按钮的值,而不是将值拉入和拉出按钮标题:
var likeCount:Int = [SET THIS FROM YOUR STORAGE] || 0
func likeButtonAction(sender:UIButton!) {
if sender.selected {
//upvote
likeCount++
println("inc \(likeCount!)")
} else {
//downvote, but do not allow negative values
if likeCount == 0{
likeCount = 0
} else {
likeCount--
}
println("dec \(likeCount!)")
}
sender.setTitle(String(likeCount!), forState: UIControlState.Normal)
sender.selected = !sender.selected
}
这将使值的跟踪保持独立,并使UI不会阻碍该过程。