我是编程新手 - 但在过去两个月里,我在学习适用于 iOS 的 Swift 方面取得了长足进步。我正在制作一个简单的打字游戏 - 我构建我的项目的方式是我有一个隐藏的 UITextView 来检测玩家按下的字符,然后我将该字符串与可见的 UITextView 的字符串匹配。
我现在要做的是添加某种动画 - 我希望单个字母淡入/淡出
我创建了一个属性字符串,将其添加到 UITextView,但我只是想不出一种方法来为字符串中的特定范围设置动画。我试过使用类似这样的东西:
UIView.animateWithDuration(1, delay: 0.5, options: .CurveEaseOut, animations: {
self.stringForPlayer.addAttribute(
NSForegroundColorAttributeName,
value: UIColor.greenColor(),
range: NSRange(location: self.rangeOfText, length: 1))
self.textViewForPlayer.attributedText = self.textForPlayer
}, completion: { finished in
println("FINISHED")}
)
运气不好。我想也许 UIView 动画只在 View 对象本身上,不能用于属性字符串。有什么想法甚至解决方法可以实现这一目标吗?感谢任何帮助,非常感谢!
最佳答案
您可以使用 transition(with:...)
做动画。在这种情况下,将单词 ipsum
淡化为绿色。例如。在 Swift 3 及更高版本中:
let range = (textView.text as NSString).range(of: "ipsum")
if range.location == NSNotFound { return }
let string = textView.attributedText.mutableCopy() as! NSMutableAttributedString
string.addAttribute(.foregroundColor, value: UIColor.green, range: range)
UIView.transition(with: textView, duration: 1.0, options: .transitionCrossDissolve, animations: {
self.textView.attributedText = string
})
最初,您还询问了在动画期间让文本变大和变小的问题,这比较复杂。但是你可以搜索文字,找到selectionRects
,拍摄这些 View 的快照,并为它们制作动画 transform
.例如:
func growAndShrink(_ searchText: String) {
let beginning = textView.beginningOfDocument
guard
let string = textView.text,
let range = string.range(of: searchText),
let start = textView.position(from: beginning, offset: string.distance(from: string.startIndex, to: range.lowerBound)),
let end = textView.position(from: beginning, offset: string.distance(from: string.startIndex, to: range.upperBound)),
let textRange = textView.textRange(from: start, to: end)
else {
return
}
textView.selectionRects(for: textRange)
.forEach { selectionRect in
guard let snapshotView = textView.resizableSnapshotView(from: selectionRect.rect, afterScreenUpdates: false, withCapInsets: .zero) else { return }
snapshotView.frame = view.convert(selectionRect.rect, from: textView)
view.addSubview(snapshotView)
UIView.animate(withDuration: 1, delay: 0, options: .autoreverse, animations: {
snapshotView.transform = CGAffineTransform(scaleX: 1.5, y: 1.5)
}, completion: { _ in
snapshotView.removeFromSuperview()
})
}
}
和
growAndShrink("consectetaur cillium”)
将导致:
如果您只是为文本的颜色设置动画,您可能希望在将其淡化为所需的颜色(使其“流行”一点)之前将其淡化为clear
,您可以使用完成
block :
func animateColor(of searchText: String) {
let range = (textView.text as NSString).range(of: searchText)
if range.location == NSNotFound { return }
let string = textView.attributedText.mutableCopy() as! NSMutableAttributedString
string.addAttribute(.foregroundColor, value: UIColor.clear, range: range)
UIView.transition(with: textView, duration: 0.25, options: .transitionCrossDissolve, animations: {
self.textView.attributedText = string
}, completion: { _ in
string.addAttribute(.foregroundColor, value: UIColor.red, range: range)
UIView.transition(with: self.textView, duration: 0.25, options: .transitionCrossDissolve, animations: {
self.textView.attributedText = string
})
})
}
导致:
有关以前版本的 Swift,请参阅 prior revision of this answer .
关于ios - 在 Swift 中动画字符串淡入/淡出,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/28245285/