swift - 解析 : loadObjects/refreshing the tableview after a pull to refresh

Question

swift

我正在努力做到这一点，当您在 tableview 上拉动刷新时，它会使用存储在 Parse.com 上的数据更新 tableview

我已经研究过了，看来我需要使用 loadObjects()

当我把它放在里面时，它说:“使用未解析的标识符‘loadObjects’

不确定这是不是我需要的..

这是我的 ViewController.swift

import UIKit
import Parse
import Bolts
import ParseUI

class EventsViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

var timer: NSTimer!
var isAnimating = false
var currentColorIndex = 0
var currentLabelIndex = 0
var customView: UIView!
var labelsArray: Array<UILabel> = []
var refreshControl: UIRefreshControl!
var testArray = [String]()
var subArray = [String]()

@IBOutlet weak var tableview: UITableView!


@IBOutlet weak var webView: UIWebView!

override func viewDidLoad() {
    super.viewDidLoad()

    tableview.delegate = self
    tableview.dataSource = self

    refreshControl = UIRefreshControl()
    tableview.addSubview(refreshControl)

    loadCustomRefreshContents()

    //refreshControl colors
    refreshControl.backgroundColor = UIColor.clearColor() //color of background
    refreshControl.tintColor = UIColor.clearColor() //color of indicator

    let query = PFQuery(className: "events")
    let runkey = query.orderByDescending("eventTitle")
    runkey.findObjectsInBackgroundWithBlock {
        (objects: [PFObject]?, error:NSError?) -> Void in

        if error == nil {


            if let objects = objects as [PFObject]! {
                for object in objects {

                    let load = object.objectForKey("eventTitle") as! String
                    self.testArray.append(load)

                    let subload = object.objectForKey("date") as! String
                    self.subArray.append(subload)

                    print(self.testArray)
                }

            }
        } else {

            print("error:\(error!) \(error!.userInfo)")
        }

    }
    sleep(3)
    do_table_refresh()

    loadViewIfNeeded()

    loadObjects()

    /*let url = NSURL(string: "https://m.facebook.com/CathedralCityMunicipal")

    let task = NSURLSession.sharedSession().dataTaskWithURL(url!) {
        (data, response, error) in

        if error == nil {

            let urlContent = NSString(data: data!, encoding: NSUTF8StringEncoding)

            print(urlContent)

            dispatch_async(dispatch_get_main_queue()) {

            self.webView.loadHTMLString(urlContent! as String, baseURL: nil)

            }

        }
    }

    task.resume()*/

    // Do any additional setup after loading the view.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

func do_table_refresh() {

    dispatch_async(dispatch_get_main_queue()) {

        self.tableview.reloadData()
        return

    }

}

func tableView(tableView:UITableView!, numberOfRowsInSection section:Int) -> Int {
    return testArray.count
}

func numberOfSectionsInTableView(tableView: UITableView) -> Int {
    return 1
}


func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCellWithIdentifier("eventcell", forIndexPath: indexPath) as! EventTableViewCell
    cell.title.text = self.testArray[indexPath.row]
    cell.subTitle.text = self.subArray[indexPath.row]
    return cell
}

//refreshes tableview; starts refresh
func loadCustomRefreshContents() {
    let refreshContents = NSBundle.mainBundle().loadNibNamed("RefreshControl", owner: self, options: nil)

    customView = refreshContents[0] as! UIView
    customView.frame = refreshControl.bounds

    for var i=0; i<customView.subviews.count; ++i {
        labelsArray.append(customView.viewWithTag(i + 1) as! UILabel)
    }

    refreshControl.addSubview(customView)

    do_table_refresh()

}

//stops refresh
func scrollViewDidEndDecelerating(scrollView: UIScrollView) {
    do_table_refresh()

    if refreshControl.refreshing {
        if !isAnimating {
            doSomething()
            animateRefreshStep1()
            self.do_table_refresh()
        }
    }
}

//cycles through colors
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
}

func doSomething() {
    timer = NSTimer.scheduledTimerWithTimeInterval(4.0, target: self, selector: "endOfWork", userInfo: nil, repeats: true)
    self.do_table_refresh()

}

func endOfWork() {
    refreshControl.endRefreshing()

    self.do_table_refresh()
    timer.invalidate()
    timer = nil
}

//first part of animation
func animateRefreshStep1() {
    isAnimating = true

    UIView.animateWithDuration(0.1, delay: 0.0, options: UIViewAnimationOptions.CurveLinear, animations: { () -> Void in
        self.labelsArray[self.currentLabelIndex].transform = CGAffineTransformMakeRotation(CGFloat(M_PI_4))
        self.labelsArray[self.currentLabelIndex].textColor = self.getNextColor()

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

            UIView.animateWithDuration(0.05, delay: 0.0, options: UIViewAnimationOptions.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 {
                        self.animateRefreshStep1()
                    }
                    else {
                        self.animateRefreshStep2()
                    }
            })
    })
}

//second part of animation
func animateRefreshStep2() {
    UIView.animateWithDuration(0.35, delay: 0.0, options: UIViewAnimationOptions.CurveLinear, animations: { () -> Void in
        self.labelsArray[0].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[1].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[2].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[3].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[4].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[5].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[6].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[7].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[8].transform = CGAffineTransformMakeScale(1.5, 1.5)
        self.labelsArray[9].transform = CGAffineTransformMakeScale(1.5, 1.5)

        }, completion: { (finished) -> Void in
            UIView.animateWithDuration(0.25, delay: 0.0, options: UIViewAnimationOptions.CurveLinear, animations: { () -> Void in
                self.labelsArray[0].transform = CGAffineTransformIdentity
                self.labelsArray[1].transform = CGAffineTransformIdentity
                self.labelsArray[2].transform = CGAffineTransformIdentity
                self.labelsArray[3].transform = CGAffineTransformIdentity
                self.labelsArray[4].transform = CGAffineTransformIdentity
                self.labelsArray[5].transform = CGAffineTransformIdentity
                self.labelsArray[6].transform = CGAffineTransformIdentity
                self.labelsArray[7].transform = CGAffineTransformIdentity
                self.labelsArray[8].transform = CGAffineTransformIdentity
                self.labelsArray[9].transform = CGAffineTransformIdentity

                }, completion: { (finished) -> Void in
                    if self.refreshControl.refreshing {
                        self.currentLabelIndex = 0
                        self.animateRefreshStep1()
                    }
                    else {
                        self.isAnimating = false
                        self.currentLabelIndex = 0
                        for var i=0; i<self.labelsArray.count; ++i {
                            self.labelsArray[i].textColor = UIColor.blackColor()
                            self.labelsArray[i].transform = CGAffineTransformIdentity
                        }
                    }
            })
    })
}

/*
// MARK: - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
    // Get the new view controller using segue.destinationViewController.
    // Pass the selected object to the new view controller.
}
*/

}

我试过让 do_table_refresh() 函数在刷新结束后运行，但 tableview 没有更新。我也尝试过使用 self.tableview.reloadData() 但也不起作用。

我不确定我做错了什么，非常感谢任何帮助!

如有任何其他信息，请随时向我询问!

感谢您的宝贵时间!

Answer 1

因此，如果您在每次拉动刷新时都尝试获取 Parse 数据，您应该始终查询它们。

将您的查询保留在一个函数中并调用 tableView.reloadData() 以便它会在您每次查询您的事件时重新加载 tableView:

func loadEvents () -> Void {

        self.testArray = []
        self.subArray = []

        let query = PFQuery(className: "events")
        let runkey = query.orderByDescending("eventTitle")
        runkey.findObjectsInBackgroundWithBlock {
            (objects: [PFObject]?, error:NSError?) -> Void in

            if error == nil {


                if let objects = objects as [PFObject]! {
                    for object in objects {

                        let load = object.objectForKey("eventTitle") as! String
                        self.testArray.append(load)

                        let subload = object.objectForKey("date") as! String
                        self.subArray.append(subload)

                        //reload TableView
                        self.tableView.reloadData()
                        print(self.testArray)
                    }

                }
            } else {

                print("error:\(error!) \(error!.userInfo)")
            }

        }

        refreshControl.endRefreshing()
}

然后在您的 ViewDidLoad()

中为您的 UIRefreshControl 添加一个 Target

 refreshControl.addTarget(self, action: Selector("loadEvents"), forControlEvents: UIControlEvents.ValueChanged)
 self.tableView.addSubview(refreshControl)

此外，您必须按如下方式声明您的 UIRefreshControl:

var refreshControl = UIRefreshControl()