轮播图
2016年11.24
//轮播图
import UIKit
class ViewController: UIViewController,UIScrollViewDelegate{
//定义一个全局变量
var scrollerView : UIScrollView! = nil
var pageC : UIPageControl! = nil
var timer : Timer! = nil
override func viewDidLoad() {
super.viewDidLoad()
let src = UIScrollView(frame: CGRect(x: 0, y: 100, width: self.view.frame.size.width, height: 300))
//全局
scrollerView = src
//设置代理
src.delegate = self
src .contentSize = CGSize(width: self.view.frame.size.width * 5, height: 300)
//整页翻动
src.isPagingEnabled = true
//触壁反弹
src.bounces = false
self.view.addSubview(src)
for index in 1...5 {
let name = "\(index).jpg"
let image = UIImage(named:name)
let x = CGFloat(index - 1) * self.view.frame.size.width
let imageView = UIImageView(frame: CGRect(x: x, y: 0, width: self.view.frame.size.width, height: 300))
imageView.image = image
src.addSubview(imageView)
}
//添加UIPageControl
let page = UIPageControl(frame: CGRect(x: 100, y: 350, width: self.view.frame.size.width - 200, height: 30))
//全局
pageC = page
page.numberOfPages = 4
page.currentPage = 0
page.addTarget(self, action: #selector(pageAction(page:)), for: .valueChanged)
self.view.addSubview(page)
//timer 自动播放
self.timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
self.timer.fire()
}
func timerAction() {
//1，获取到当前的offset, 2，offset.x + width. 3， if 到第四个 跳回到第一个
let offset = self.scrollerView.contentOffset
let width = self.view.frame.size.width
//让scrollerView进行滑动 offset.x+width:加宽度 走到下一张图片
scrollerView.setContentOffset(CGPoint(x: offset.x + width,y:offset.y ), animated: true)
//if 到第四个了，跳动到第一个
if scrollerView.contentOffset.x >= width * 4 {
let point = CGPoint(x: 0, y: 0)
scrollerView.contentOffset = point
}
}
//page是局部变量，必须写上page:UIPageControl
func pageAction(page:UIPageControl) {
let index = page.currentPage;
let point = CGPoint(x: CGFloat(index) * self.view.frame.size.width, y: 0)
//修改偏移量
self.scrollerView.setContentOffset(point, animated: true)
}
//开始拖拽
func scrollViewWillBeginDragging(_ scrollView: UIScrollView) {
self.timer.invalidate()
self.timer = nil
}
//结束拖拽
func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
self.timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)
//一秒之后开启
let time = DispatchTime.now() + Double(Int64(1*NSEC_PER_SEC))/Double(NSEC_PER_SEC)
DispatchQueue.main.asyncAfter(deadline:time) {
//循环绑定
if let _ = self.timer {
self.timer.fire()
}
}
}
//滑动会执行的方法
func scrollViewDidScroll(_ scrollView: UIScrollView) {
//获取到偏移量，根据偏移量定位到第几个点
let x = scrollerView.contentOffset.x
let width = self.view.frame.size.width
if (x >= width * 4) {
self.pageC.currentPage = 0
}else {
self.pageC.currentPage = Int(x / width)
}
//这一行代码强制转换 同下。
//self.pageC.currentPage = Int(x / width)
// switch x {
// case 0:
// self.pageC.currentPage = 0
// case 1 * width:
// self.pageC.currentPage = 1
// case 2 * width:
// self.pageC.currentPage = 2
// case 3 * width:
// self.pageC.currentPage = 3
//
// default:
// print("other")
//
// }
}
}
