Swfit - 使用自定义的UIRefreshControl下拉刷新界面

默认 UIRefreshControl 下拉刷新界面是一个菊花进度条+一段描述文字，略显单调。其实我们可以使用自己创建的界面视图，方便我们实现各种效果。比如添加个动态图片，添加个动画效果什么的。

import UIKit

class ViewController: UIViewController,UITableViewDelegate,UITableViewDataSource {
    
    //新闻列表
    @IBOutlet weak var newsTableView: UITableView!
    
    //新闻数组集合
    var dataArray:[HanggeArticle] = [HanggeArticle]()
    
    //拉刷新控制器
    var refreshControl = UIRefreshControl()
    
    var customView: UIView!
    
    var labelsArray: Array<UILabel> = []
    
    var currentColorIndex = 0
    
    var currentLabelIndex = 0
    
    var timer: NSTimer!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        //添加刷新
        refreshControl.addTarget(self, action: "refreshData",
            forControlEvents: UIControlEvents.ValueChanged)
        
        //背景色和tint颜色都要清除,保证自定义下拉视图高度自适应
        refreshControl.backgroundColor = UIColor.clearColor()
        refreshControl.tintColor = UIColor.clearColor()
        
        newsTableView.addSubview(refreshControl)
        loadData()
        
        //加载自定义刷新界面
        loadCustomRefreshView()
    }
    
    
    //自定义刷新界面
    func loadCustomRefreshView() {
        let refreshContents = NSBundle.mainBundle().loadNibNamed("RefreshView",
            owner: self, options: nil)
        
        customView = refreshContents[0] as! UIView
        customView.frame = refreshControl.bounds
        
        customView.alpha = 0.0
        
        for var i=0; i<customView.subviews.count; ++i {
            labelsArray.append(customView.viewWithTag(i + 1) as! UILabel)
        }
        
        refreshControl.addSubview(customView)
    }
    
    //滚动视图开始拖动
    func scrollViewWillBeginDragging(scrollView: UIScrollView) {
        if !refreshControl.refreshing {
            self.labelsArray[0].text = "下"
            self.labelsArray[1].text = "拉"
            self.labelsArray[2].text = "刷"
            self.labelsArray[3].text = "新"
            self.labelsArray[4].text = "数"
            self.labelsArray[5].text = "据"
        }
    }
    
    //视图拖动
    func scrollViewDidScroll(scrollView: UIScrollView) {
        //加载界面透明度改变
        let sg = ( scrollView.contentOffset.y * -1 ) / 60.0
        customView.alpha = sg
    }
    
    // 刷新数据
    func refreshData() {
        self.labelsArray[0].text = "数"
        self.labelsArray[1].text = "据"
        self.labelsArray[2].text = "加"
        self.labelsArray[3].text = "载"
        self.labelsArray[4].text = "中"
        self.labelsArray[5].text = "..."
        
        //播放动画
        playAnimateRefresh()
        
        //模拟加载数据
        timer = NSTimer.scheduledTimerWithTimeInterval(3.0, target: self,
            selector: "loadData", userInfo: nil, repeats: true)
    }
    
    //播放文字动画
    func playAnimateRefresh() {
        //文字放大，变色动画
        UIView.animateWithDuration(0.15, delay: 0.0,
            options: .CurveLinear, animations: { () -> Void in
                
            self.labelsArray[self.currentLabelIndex].transform =
                CGAffineTransformMakeScale(1.5, 1.5)
            self.labelsArray[self.currentLabelIndex].textColor =
                self.getNextColor()
            
            }, completion: { (finished) -> Void in
                
                //文字样式还原动画
                UIView.animateWithDuration(0.1, delay: 0.0,
                    options: .CurveLinear, animations: { () -> Void in
                        
                    self.labelsArray[self.currentLabelIndex].transform =
                        CGAffineTransformIdentity
                    self.labelsArray[self.currentLabelIndex].textColor =
                        UIColor.blackColor()
                    
                    }, completion: { (finished) -> Void in
                        ++self.currentLabelIndex
                        
                        if self.currentLabelIndex == self.labelsArray.count - 1 {
                            self.currentLabelIndex = 0
                        }
                        
                        //没加载完则继续播放动画
                        if self.refreshControl.refreshing {
                            self.playAnimateRefresh()
                        }else{
                            self.currentLabelIndex = 0
                        }
                })
        })
    }
    
    //计时器时间到,加载数据
    func loadData() {
        //移除老数据
        self.dataArray.removeAll()
        //随机添加5条新数据（时间是当前时间）
        for _ in 0..<5 {
            let atricle = HanggeArticle(title: "新闻标题\(Int(arc4random()%1000))",
                createDate: NSDate())
            self.dataArray.append(atricle)
        }
        self.newsTableView.reloadData()
        self.refreshControl.endRefreshing()
        
        timer?.invalidate()
        timer = nil
    }
    
    // 返回记录数
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return dataArray.count;
    }
    
    // 返回单元格内容
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath)
        -> UITableViewCell {
            let cell = UITableViewCell(style: UITableViewCellStyle.Subtitle,
                reuseIdentifier: "myCell")
            
            //设置单元格标题
            let atricle: HanggeArticle = dataArray[indexPath.row] as HanggeArticle
            cell.textLabel?.text = atricle.title
            
            //设置单元格副标题
            let dateFormatter = NSDateFormatter()
            dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
            let str = dateFormatter.stringFromDate(atricle.createDate)
            cell.detailTextLabel?.text = str
            
            return cell;
    }
    
    //获取下一个颜色
    func getNextColor() -> UIColor {
        var colorsArray: Array<UIColor> = [UIColor.magentaColor(),
            UIColor.brownColor(), UIColor.yellowColor(), UIColor.redColor(),
            UIColor.greenColor(), UIColor.blueColor(), UIColor.orangeColor()]
        
        if currentColorIndex == colorsArray.count {
            currentColorIndex = 0
        }
        
        let returnColor = colorsArray[currentColorIndex]
        ++currentColorIndex
        
        return returnColor
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }
}

//新闻结构体
struct HanggeArticle {
    var title:String
    var createDate:NSDate
}