我刚接触Swift 2.0,想学习它,对动画很感兴趣,并尝试编写了一些代码以逐个字符显示屏幕上的消息。
我写了这个代码,它能工作,但我不禁想知道是否可以使用CALayers或alpha值进行操作?或者使用一些动画工具,更加符合Swift的特点。这个程序感觉有些笨重,类似于1977年的风格。
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
let supertext = "A long time ago, in a galaxy far, far away ..."
let round = supertext.characters.count
for i in 0...round {
let delay = Double(i)/10
let subtext = supertext[supertext.startIndex..<supertext.startIndex.advancedBy(i)]
NSTimer.scheduledTimerWithTimeInterval(delay, target: self, selector: "ghostText:", userInfo: ["theText" :subtext], repeats: false)
}
}
var view3:UITextView = UITextView()
func ghostText(timer:NSTimer) {
view3.removeFromSuperview()
let userInfo = timer.userInfo as! Dictionary<String, AnyObject>
let tempText:NSString = (userInfo["theText"] as! NSString)
print(tempText)
let font = UIFont(name: "Georgia", size: 18.0) ?? UIFont.systemFontOfSize(18.0)
let textFont = [NSFontAttributeName:font]
let subChararacter = NSAttributedString(string: String(tempText), attributes: textFont)
view3.frame = CGRect(x: 100, y: 120, width: CGRectGetWidth(self.view.frame), height: CGRectGetWidth(self.view.frame)-20)
view3.attributedText = subChararacter
self.view.addSubview(view3)
}