問題描述
對于我使用 UIScrollView 的第一個挑戰，我修改了 ViewController.swift(已更正)
導入 UIKit類視圖控制器:UIViewController，UIScrollViewDelegate {讓 scrollView = UIScrollView(frame: CGRect(x: 0, y: 0, width: 320, height: 480))var 視圖 = [UIView]()變量標簽 = [UILabel]()變種顏色:[UIColor] = [UIColor.red，UIColor.magenta，UIColor.blue，UIColor.cyan，UIColor.green，UIColor.yellow]var 框架:CGRect = CGRect.zerovar pageControl: UIPageControl = UIPageControl(frame: CGRect(x: 50, y: 500, width: 200, height: 50))覆蓋 func viewDidLoad() {super.viewDidLoad()初始化視圖和標簽()配置頁面控制()scrollView.delegate = 自我self.view.addSubview(scrollView)對于 0..擴展
擴展 UILabel{var defaultFont: UIFont?{得到 { 返回 self.font }設置 { self.font = newValue }}}每幀標簽的中心點必須偏移內容視圖的原點(正如 Baglan 指出的).我已經相應地修改了以下代碼行.
標簽[Int(index)].center = CGPoint(x: (view.frame.midX + frame.origin.x), y: view.frame.midY)For my first challenge using UIScrollView I modified this example to make UIScrollView display not just another background colour but another UIView and UILabel on each page. But I could have just as easily chosen to display objects like UITableView, UIButton or UIImage.
Potentially, UIScrollView could be much more than a giant content view where users scroll from one part to the next, e.g., some pages might have a UIButton that takes a user to a specific page, the same way we use books.
Code Improvements
My question has evolved since I first posted it. Initially the labels piled up on page 1 (as shown below) but this has now been corrected. I also included this extension to make the font larger.
Further improvement ?
As the code evolved I became more aware of other issues e.g. iPhone 5 images (below) appear differently on iPhone 7 where the UILabel is centred but not the UIView. So my next challenge is possibly to learn how to combine UIScrollView with Autolayout. I invite anyone to spot other things that might be wrong.
ViewController.swift (corrected)
import UIKit
class ViewController: UIViewController,UIScrollViewDelegate {
let scrollView = UIScrollView(frame: CGRect(x: 0, y: 0, width: 320, height: 480))
var views = [UIView]()
var lables = [UILabel]()
var colors:[UIColor] = [UIColor.red, UIColor.magenta, UIColor.blue, UIColor.cyan, UIColor.green, UIColor.yellow]
var frame: CGRect = CGRect.zero
var pageControl: UIPageControl = UIPageControl(frame: CGRect(x: 50, y: 500, width: 200, height: 50))
override func viewDidLoad() {
super.viewDidLoad()
initialiseViewsAndLables()
configurePageControl()
scrollView.delegate = self
self.view.addSubview(scrollView)
for index in 0..<colors.count {
frame.origin.x = self.scrollView.frame.size.width * CGFloat(index)
frame.size = self.scrollView.frame.size
self.scrollView.isPagingEnabled = true
views[index].frame = frame
views[index].backgroundColor = colors[Int(index)]
views[index].layer.cornerRadius = 20
views[index].layer.masksToBounds = true
lables[index].frame = frame
lables[index].center = CGPoint(x: (view.frame.midX + frame.origin.x), y: view.frame.midY)
lables[index].text = String(index + 1)
lables[index].defaultFont = UIFont(name: "HelveticaNeue", size: CGFloat(200))
lables[index].textAlignment = .center
lables[index].textColor = .black
let subView1 = views[index]
let subView2 = lables[index]
self.scrollView .addSubview(subView1)
self.scrollView .addSubview(subView2)
}
print(views, lables)
self.scrollView.contentSize = CGSize(width: self.scrollView.frame.size.width * CGFloat(colors.count), height: self.scrollView.frame.size.height)
pageControl.addTarget(self, action: Selector(("changePage:")), for: UIControlEvents.valueChanged)
}
func initialiseViewsAndLables() {
// Size of views[] and lables[] is linked to available colors
for index in 0..<colors.count {
views.insert(UIView(), at:index)
lables.insert(UILabel(), at: index)
}
}
func configurePageControl() {
// Total number of available pages is based on available colors
self.pageControl.numberOfPages = colors.count
self.pageControl.currentPage = 0
self.pageControl.backgroundColor = getColour()
self.pageControl.pageIndicatorTintColor = UIColor.black
self.pageControl.currentPageIndicatorTintColor = UIColor.green
self.view.addSubview(pageControl)
}
func getColour() -> UIColor {
let index = colors[pageControl.currentPage]
return (index)
}
func changePage(sender: AnyObject) -> () {
scrollView.setContentOffset(CGPoint(x: CGFloat(pageControl.currentPage) * scrollView.frame.size.width, y: 0), animated: true)
}
func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
let pageNumber = round(scrollView.contentOffset.x / scrollView.frame.size.width)
pageControl.currentPage = Int(pageNumber)
pageControl.backgroundColor = getColour()
}
}
Extension
extension UILabel{
var defaultFont: UIFont? {
get { return self.font }
set { self.font = newValue }
}
}
The centre point of the lable on each frame must be offset by the origin of the content view (as Baglan pointed out). I've modified the following line of code accordingly.
lables[Int(index)].center = CGPoint(x: (view.frame.midX + frame.origin.x), y: view.frame.midY)
這篇關于我最初的 UIScrollView 問題現在似乎與自動布局有關的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！