swift与js特殊需求交互

var webview = UIWebView(frame: CGRect(x: 0, y: 0, width: screenWidth, height: webviewHeight))
webview.delegate = self
webview.scrollView.bounces = false
webview.loadRequest(NSURLRequest(URL: NSURL(string: _url)!))
self.view.addSubview(webview)

1.swift调用js

func webViewDidFinishLoad(webView: UIWebView) {
  self.webview.stringByEvaluatingJavaScriptFromString("document.body.scrollHeight")//正常获取网页内容长度的方法
}

2.js调用swift

客户端定义好方法,并且与服务端约定好协议 scheme+host+query
如：myapp://refresh?type=1&data=2

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
  guard let url = request.URL else{
            return true
  }
  guard url.scheme == "myapp"{
    return true
  } 
  guard let action == url.host else{
    return true
  }
  let parStr = url.query ?? ""
  handleAction(action, par: par)
  return true
}
func handleAction(action:String,par:String){
   if action == " refresh"{
        let parDict = par.toURLParameterDict()
        let type = parDict["type"] as! Int
        let data = parDict["data"] as! String 
        if type == 1{
          refreshView(data)
        }
    }
}
//执行原生事件
func refreshView(data:Int){
  //handleData
    ...
    self.tableView.reloadData()
}
//解析URL参数转换成Dictionary
extension String{
    func toURLParameterDict()->NSDictionary{
        guard !self.isEmpty{
          return NSDictionary()
        }
        let dict = NSMutableDictionary()
        let arr = self.componentsSeparatedByString("&")
        for one in arr{
            let pararr = one.componentsSeparatedByString("=")
            let key = pararr.first!
            let value = pararr.last!
            dict[key] = value
        }
        
        return NSDictionary(dictionary: dict)
    }
}
    

3.处理js中ajax加载完后cell内容自适应（webview在tableView中的情况）

**方法1：通过kov监听webview的ajax加载完成的属性，来重新获取webview内容高度

//TODO:理论是可实现的，后续添加

**方法2：通过js调用原生告知ajax加载完成
myapp://common.loadfinish

func webView(webView: UIWebView, shouldStartLoadWithRequest request: NSURLRequest, navigationType: UIWebViewNavigationType) -> Bool {
  guard let url = request.URL else{
            return true
  }
  guard url.scheme == "myapp"{
    return true
  } 
  guard let action == url.host else{
    return true
  }
  if action = "common.loadfinish"{
    let newHeight = CGFloat(Float(webView.stringByEvaluatingJavaScriptFromString("document.body.scrollHeight")!)!)
  ...
  //reloadTableView
  }

4.处理h5中的webp图片不显示

google：
1.get webp image url ;
2.download image ;
3.use base64 library ,embed same data with <img src> tag.
**思路：

<1>获取html中所有的图片

<2>如果是webp图片需要替换成base64数据

<3>将新的图片数据写入html标签中

@T7S{[6TF}64]OD3W`KAJ53.jpg

func webViewDidFinishLoad(webView: UIWebView) {
  guard let oldimgurl = webView.stringByEvaluatingJavaScriptFromString("function getlist (){var imglist='';$.each($('#news-article img'), function(i){if (i == 0){imglist = $(this).attr('src')}else{imglist =  imglist+','+$(this).attr('src')}});return imglist;} getlist();") else{
  return
  }
  let imageurllist = oldimgurl.toImgArr()  
   var imgliststr = ""
    for i in 0..<imageurllist.count{
      var reaultstr = ""
      if i != 0{
        reaultstr+=","
      }
      let defaultimgstr = UIImagePNGRepresentation(defaultImg!)!.base64EncodedStringWithOptions(.Encoding64CharacterLineLength).encodeToURL()
      guard let url = NSURL(string:imageurllist[i]) else{
        reaultstr+=defaultimgstr
        imgliststr+=reaultstr
        return
      }
      guard let data = NSData(contentsOfURL: url) else{
        reaultstr+=defaultimgstr
        imgliststr+=reaultstr
        return
      }
      if data.isWebP(){
        let img = UIImage(webPData: data)
        guard let pngdata = UIImagePNGRepresentation(img) else{
          reaultstr+=defaultimgstr
          imgliststr+=reaultstr
          return 
        }
        let base64str = pngdata.base64EncodedStringWithOptions(.Encoding64CharacterLineLength).encodeToURL()
        reaultstr+=base64str
        imgliststr+=reaultstr
       }else{
        reaultstr+=imageurllist[i]
        imgliststr+=reaultstr
       }
      }
  webView.stringByEvaluatingJavaScriptFromString("function setlist(){var imglist = '\(imgliststr)';var imglist_arr = imglist.split(',');$.each($('#news-article img'), function(i) {if(imglist_arr[i].indexOf('http')>=0){$(this).attr('src', imglist_arr[i]);}else{$(this).attr('src', 'data:image/png;base64,' + imglist_arr[i]);}});}setlist();")
}