             BlackStatusBar()
         }
         
-        if (-offSetY <= 40 && -offSetY >= 20) {
+        if (-offSetY <= 60 && -offSetY >= 50) {
             if !viewModel.hasPrevious {
                 return
             }

            self.isLoading = true
            //上一条新闻
            getPreviousNews()
        }else if (-offSetY > 40) {//到－80 让webview不再能被拉动
            self.webView.scrollView.contentOffset = CGPointMake(0, -40);
        }
        
        if (offSetY + ScreenHeight > scrollView.contentSize.height + 20  && !self.webView.scrollView.dragging) {
            if !viewModel.hasNext {
                return
            }

        backgroundImg = UIImageView()
        backgroundImg.contentMode = .ScaleAspectFill
        backgroundImg.clipsToBounds = true
        backgroundImg.frame = CGRectMake(0, -60, ScreenWidth, CGFloat(IN_WINDOW_HEIGHT+60))
        
        titleLabel = UILabel()
        titleLabel.numberOfLines = 0
