IOS UIWebView 下拉刷新功能的简单实现

1.运行效果图

2.swift 代码的实现

import UIKit

class RefreshWebViewController: UIViewController,UIScrollViewDelegate,UIWebViewDelegate{

@IBOutlet weak var webView: UIWebView!

//刷新控件view

private var header:UIView!

//下拉到50时松开刷新

private let pullHeight:CGFloat=50

//刷新提示文字

private var headerText:UILabel!

//刷新指示器(旋转小圆圈)

private var activityView:UIActivityIndicatorView!

//标记刷新状态

private var isRefreshing=false

override func viewDidLoad() {

super.viewDidLoad()

self.webView.scrollView.delegate=self

self.webView.delegate=self

self.automaticallyAdjustsScrollViewInsets=false

initHeaderView()

loading()

}

//定义下拉刷新控件

private func initHeaderView( )  {

self.header=UIView(frame: CGRectMake(0,0, self.view.frame.width,200))

self.header.backgroundColor=UIColor.darkGrayColor()

self.headerText=UILabel(frame: CGRectMake((self.view.frame.width-120)/2,10,150,30))

self.headerText.text="下拉刷新"

self.headerText.textAlignment=NSTextAlignment.Center

self.headerText.textColor=UIColor.whiteColor()

self.header.addSubview(headerText)

self.activityView=UIActivityIndicatorView(frame: CGRectMake( self.headerText.frame.origin.x-5,15,20,20))

self.header.addSubview(activityView)

self.webView.insertSubview(header, atIndex: 0)

}

//加载网页

func loading( ) {

self.webView.loadRequest(NSURLRequest(URL: NSURL(string:"http://www.hao123.com")!))

}

//scroll滚动时调用

func scrollViewDidScroll(scrollView: UIScrollView) {

if isRefreshing{

return

}

//当下拉到pullHeight高度时松开即可刷新

if scrollView.contentOffset.y <= -pullHeight{

self.headerText.text="松开立即刷新"

}else{

self.headerText.text="下拉刷新"

}

}

//    scrollview停止滚动时调用

func scrollViewDidEndDragging(scrollView: UIScrollView, willDecelerate decelerate: Bool) {

if isRefreshing{

return

}

if scrollView.contentOffset.y <= -pullHeight{

refreshing()

}

}

//开始刷新

func refreshing( )   {

isRefreshing=true

self.headerText.text="正在刷新..."

self.activityView.startAnimating()

UIView.animateWithDuration(0.5, delay: 0,   options: .CurveEaseOut, animations: {

// 设置刷新控件停留

var offY = self.webView.scrollView.contentInset

offY.top += self.pullHeight

self.webView.scrollView.contentInset=offY

}, completion:{(_)->Void in

})

self.loading()

}

//刷新结束

func refreshEnd() {

self.headerText.text="刷新成功"

self.activityView.stopAnimating()

UIView.animateWithDuration(1, delay: 0,   options: .CurveEaseOut, animations: {

//恢复刷新控件到原始位置

var offY = self.webView.scrollView.contentInset

offY.top -= self.pullHeight

self.webView.scrollView.contentInset=offY

}, completion:{(_)->Void in

self.isRefreshing=false

self.headerText.text="下拉刷新"

})

}

//网页加载完成

func webViewDidFinishLoad(webView: UIWebView) {

if isRefreshing{

refreshEnd()

}

}

}