如何在Swift中使用pull刷新?

问题描述 投票:197回答:14

我正在使用swift构建一个RSS阅读器,需要实现pull to reload功能。

这是我试图这样做的方式。

class FirstViewController: UIViewController,
    UITableViewDelegate, UITableViewDataSource {

   @IBOutlet var refresh: UIScreenEdgePanGestureRecognizer
   @IBOutlet var newsCollect: UITableView

   var activityIndicator:UIActivityIndicatorView? = nil

   override func viewDidLoad() {
       super.viewDidLoad()
       self.newsCollect.scrollEnabled = true
      // Do any additional setup after loading the view, typically from a nib.

      if nCollect.news.count <= 2{
          self.collectNews()
       }
      else{
          self.removeActivityIndicator()
       }
      view.addGestureRecognizer(refresh)
   }



@IBAction func reload(sender: UIScreenEdgePanGestureRecognizer) {
    nCollect.news = News[]()
    return newsCollect.reloadData()
}

我正进入(状态 :

属性'self.refresh'未在super.init调用中初始化

请帮助我理解手势识别器的行为。一个工作示例代码将是一个很好的帮助。

谢谢。

ios swift xcode uirefreshcontrol
14个回答
515
投票

Pull to refresh是在iOS中构建的。你可以像swift那样做

var refreshControl = UIRefreshControl()

override func viewDidLoad() {
   super.viewDidLoad()

   refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")
   refreshControl.addTarget(self, action: #selector(refresh(_:)), for: UIControl.Event.valueChanged)
   tableView.addSubview(refreshControl) // not required when using UITableViewController
}

@objc func refresh(sender:AnyObject) {
   // Code to refresh table view  
}

在某些时候,你可以结束刷新。

refreshControl.endRefreshing()

1
投票

我建议在每个班级中使用pull To Refresh扩展。

1)制作一个空的swift文件:File - New - File - Swift File。

2)添加以下内容

    //  AppExtensions.swift

    import Foundation
    import UIKit    

    var tableRefreshControl:UIRefreshControl = UIRefreshControl()    

    //MARK:- VIEWCONTROLLER EXTENSION METHODS
    public extension UIViewController
    {
        func makePullToRefreshToTableView(tableName: UITableView,triggerToMethodName: String){

            tableRefreshControl.attributedTitle = NSAttributedString(string: "TEST: Pull to refresh")
            tableRefreshControl.backgroundColor = UIColor.whiteColor()
            tableRefreshControl.addTarget(self, action: Selector(triggerToMethodName), forControlEvents: UIControlEvents.ValueChanged)
            tableName.addSubview(tableRefreshControl)
        }
        func makePullToRefreshEndRefreshing (tableName: String)
        {
            tableRefreshControl.endRefreshing()
//additional codes

        }
    }    

3)在View Controller中将这些方法称为:

  override func viewWillAppear(animated: Bool) {

self.makePullToRefreshToTableView(bidderListTable, triggerToMethodName: "pullToRefreshBidderTable")
}

4)在某些时候你想结束刷新:

  func pullToRefreshBidderTable() {
self.makePullToRefreshEndRefreshing("bidderListTable")    
//Code What to do here.
}
OR    
self.makePullToRefreshEndRefreshing("bidderListTable")

1
投票

为了刷新我正在使用

DGElasticPullToRefresh

https://github.com/gontovnik/DGElasticPullToRefresh

安装

在'DGElasticPullToRefresh'下

import DGElasticPullToRefresh

并将此函数放入您的swift文件并从您的调用此函数

覆盖func viewWillAppear(_ animated:Bool)

     func Refresher() {
      let loadingView = DGElasticPullToRefreshLoadingViewCircle()
      loadingView.tintColor = UIColor(red: 255.0/255.0, green: 255.0/255.0, blue: 255.0/255.0, alpha: 1.0)
      self.table.dg_addPullToRefreshWithActionHandler({ [weak self] () -> Void in

          //Completion block you can perfrom your code here.

           print("Stack Overflow")

           self?.table.dg_stopLoading()
           }, loadingView: loadingView)
      self.table.dg_setPullToRefreshFillColor(UIColor(red: 255.0/255.0, green: 57.0/255.0, blue: 66.0/255.0, alpha: 1))
      self.table.dg_setPullToRefreshBackgroundColor(self.table.backgroundColor!)
 }

并且不要忘记删除引用,而视图将消失

删除pull以刷新将此代码放入您的

覆盖func viewDidDisappear(_ animated:Bool)

override func viewDidDisappear(_ animated: Bool) {
      table.dg_removePullToRefresh()

 }

它看起来会像

enter image description here

快乐编码:)


0
投票

你可以使用tableView的这个子类:

import UIKit

protocol PullToRefreshTableViewDelegate : class {
    func tableViewDidStartRefreshing(tableView: PullToRefreshTableView)
}

class PullToRefreshTableView: UITableView {

    @IBOutlet weak var pullToRefreshDelegate: AnyObject?
    private var refreshControl: UIRefreshControl!
    private var isFirstLoad = true

    override func willMoveToSuperview(newSuperview: UIView?) {
        super.willMoveToSuperview(newSuperview)

        if (isFirstLoad) {
            addRefreshControl()
            isFirstLoad = false
        }
    }

    private func addRefreshControl() {
        refreshControl = UIRefreshControl()
        refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")
        refreshControl.addTarget(self, action: "refresh", forControlEvents: .ValueChanged)
        self.addSubview(refreshControl)
    }

    @objc private func refresh() {
       (pullToRefreshDelegate as? PullToRefreshTableViewDelegate)?.tableViewDidStartRefreshing(self)
    }

    func endRefreshing() {
        refreshControl.endRefreshing()
    }

}

1 - 在界面构建器中将tableView的类更改为PullToRefreshTableView或以编程方式创建PullToRefreshTableView

2 - 在视图控制器中实现PullToRefreshTableViewDelegate

3 - 当表视图开始刷新时,将在视图控制器中调用tableViewDidStartRefreshing(tableView: PullToRefreshTableView)

4 - 打电话给yourTableView.endRefreshing()完成清爽


0
投票

这就是我使用Xcode 7.2工作的方式,我认为这是一个主要的错误。我在我的UITableViewController里面的viewWillAppear里面使用它

refreshControl = UIRefreshControl()
refreshControl!.addTarget(self, action: "configureMessages", forControlEvents: .ValueChanged)
refreshControl!.beginRefreshing()

configureMessages()

func configureMessages() {
    // configuring messages logic here

    self.refreshControl!.endRefreshing()
}

正如你所看到的,我确实必须在设置我的configureMessage()之后调用UIRefreshControl方法然后在那之后,随后的刷新将正常工作。


0
投票

细节

  • Xcode版本10.3(10G8),Swift 5

特征

  • 能够以编程方式“刷新”
  • 防止多次“拉动到刷新”事件
  • 能够在视图控制器切换时继续动画活动指示器(例如,在TabController的情况下)

import UIKit

class RefreshControl: UIRefreshControl {

    private weak var actionTarget: AnyObject?
    private var actionSelector: Selector?
    override init() { super.init() }

    convenience init(actionTarget: AnyObject?, actionSelector: Selector) {
        self.init()
        self.actionTarget = actionTarget
        self.actionSelector = actionSelector
        addTarget()
    }

    private func addTarget() {
        guard let actionTarget = actionTarget, let actionSelector = actionSelector else { return }
        addTarget(actionTarget, action: actionSelector, for: .valueChanged)
    }

    required init?(coder aDecoder: NSCoder) { super.init(coder: aDecoder) }

    func endRefreshing(deadline: DispatchTime? = nil) {
        guard let deadline = deadline else { endRefreshing(); return }
        DispatchQueue.global(qos: .default).asyncAfter(deadline: deadline) { [weak self] in
            DispatchQueue.main.async { self?.endRefreshing() }
        }
    }

    func refreshActivityIndicatorView() {
        guard let selector = actionSelector else { return }
        let _isRefreshing = isRefreshing
        removeTarget(actionTarget, action: selector, for: .valueChanged)
        endRefreshing()
        if _isRefreshing { beginRefreshing() }
        addTarget()
    }

    func generateRefreshEvent() {
        beginRefreshing()
        sendActions(for: .valueChanged)
    }
}

public extension UIScrollView {

    private var _refreshControl: RefreshControl? { return refreshControl as? RefreshControl }

    func addRefreshControll(actionTarget: AnyObject?, action: Selector, replaceIfExist: Bool = false) {
        if !replaceIfExist && refreshControl != nil { return }
        refreshControl = RefreshControl(actionTarget: actionTarget, actionSelector: action)
    }

    func scrollToTopAndShowRunningRefreshControl(changeContentOffsetWithAnimation: Bool = false) {
        _refreshControl?.refreshActivityIndicatorView()
        guard   let refreshControl = refreshControl,
                contentOffset.y != -refreshControl.frame.height else { return }
        setContentOffset(CGPoint(x: 0, y: -refreshControl.frame.height), animated: changeContentOffsetWithAnimation)
    }

    private var canStartRefreshing: Bool {
        guard let refreshControl = refreshControl, !refreshControl.isRefreshing else { return false }
        return true
    }

    func startRefreshing() {
        guard canStartRefreshing else { return }
        _refreshControl?.generateRefreshEvent()
    }

    func pullAndRefresh() {
        guard canStartRefreshing else { return }
        scrollToTopAndShowRunningRefreshControl(changeContentOffsetWithAnimation: true)
        _refreshControl?.generateRefreshEvent()
    }

    func endRefreshing(deadline: DispatchTime? = nil) { _refreshControl?.endRefreshing(deadline: deadline) }
}

用法

// Add refresh control to UICollectionView / UITableView / UIScrollView
private func setupTableView() {
    let tableView = UITableView()
    // ...
    tableView.addRefreshControll(actionTarget: self, action: #selector(refreshData))
}

@objc func refreshData(_ refreshControl: UIRefreshControl) {
    tableView?.endRefreshing(deadline: .now() + .seconds(3))
}

// Stop refreshing in UICollectionView / UITableView / UIScrollView
tableView.endRefreshing()

// Simulate pull to refresh in UICollectionView / UITableView / UIScrollView
tableView.pullAndRefresh()

完整样本

不要忘记在此处添加解决方案代码

import UIKit

class ViewController: UIViewController {

    private weak var tableView: UITableView?

    override func viewDidLoad() {
        super.viewDidLoad()
        setupTableView()
    }

    private func setupTableView() {
        let tableView = UITableView()
        view.addSubview(tableView)
        tableView.translatesAutoresizingMaskIntoConstraints = false
        tableView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        tableView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        tableView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
        tableView.dataSource = self
        tableView.delegate = self
        tableView.addRefreshControll(actionTarget: self, action: #selector(refreshData))
        self.tableView = tableView
    }
}

extension ViewController {
    @objc func refreshData(_ refreshControl: UIRefreshControl) {
        print("refreshing")
        tableView?.endRefreshing(deadline: .now() + .seconds(3))
    }
}

extension ViewController: UITableViewDataSource {
    func numberOfSections(in tableView: UITableView) -> Int { return 1 }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { return 20 }
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = UITableViewCell()
        cell.textLabel?.text = "\(indexPath)"
        return cell
    }
}

extension ViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        tableView.pullAndRefresh()
    }
}

-1
投票

其他答案是正确的但更多细节检查此帖Pull to Refresh

在Storyboard中启用刷新

当您使用UITableViewController时,解决方案非常简单:首先,在故事板中选择表视图控制器,打开属性检查器,然后启用刷新:

UITableViewController配备了一个开箱即用的UIRefreshControl引用。您只需要连接一些内容即可在用户下拉时启动并完成刷新。

覆盖viewDidLoad()

在覆盖viewDidLoad()时,添加目标以处理刷新,如下所示:

override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typically from a nib.

    self.refreshControl?.addTarget(self, action: "handleRefresh:", forControlEvents: UIControlEvents.ValueChanged)
}
  1. 由于我已将“handleRefresh:”(注意冒号!)指定为action参数,因此我需要在此UITableViewController类中定义一个具有相同名称的函数。此外,该函数应该采用一个参数
  2. 我们希望为名为ValueChanged的UIControlEvent调用此操作
  3. 别忘了打电话给refreshControl.endRefreshing()

欲了解更多信息,请参阅链接,所有信用都转到该帖子


127
投票

故事板和快速解决方案......

1.)打开.storyboard文件,在故事板中选择TableViewController,并在“实用程序”中“启用”表视图控制器 - 刷新功能。

2.)打开关联的UITableViewController-Class并将以下行添加到viewDidLoad-Method中。

self.refreshControl?.addTarget(self, action: "refresh:", forControlEvents: UIControlEvents.ValueChanged)

编辑Swift 5.0:

self.refreshControl?.addTarget(self, action: #selector(refresh), for: UIControl.Event.valueChanged)

或者在Swift 2.2中:

self.refreshControl?.addTarget(self, action: #selector(TestTableViewController.refresh(_:)), forControlEvents: UIControlEvents.ValueChanged)

3.)在viewDidLoad-Method上方添加以下方法

func refresh(sender:AnyObject)
{
    // Updating your data here...

    self.tableView.reloadData()
    self.refreshControl?.endRefreshing()
}

64
投票

iOS 10 - Swift 3(也适用于iOS 11 - Swift 4)

我想提一下自iOS 10以来一直包含的PRETTY COOL功能,它是:

目前,UIRefreshControl直接支持UICollectionViewUITableViewUIScrollView

这些视图中的每一个都有refreshControl实例属性,这意味着不再需要在滚动视图中将其添加为子视图,您所要做的就是:

@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLoad() {
    super.viewDidLoad()

    let refreshControl = UIRefreshControl()
    refreshControl.addTarget(self, action: #selector(doSomething), for: .valueChanged)

    // this is the replacement of implementing: "collectionView.addSubview(refreshControl)"
    collectionView.refreshControl = refreshControl
}

func doSomething(refreshControl: UIRefreshControl) {
    print("Hello World!")

    // somewhere in your code you might need to call:
    refreshControl.endRefreshing()
}

就个人而言,我觉得将它作为滚动视图的属性处理比将其添加为子视图更自然,特别是因为作为UIRefreshControl的超级视图的唯一合适的视图是滚动视图,即使用UIRefreshControl的功能仅是使用滚动视图时很有用;这就是为什么这种方法应该更明显地设置刷新控制视图。

但是,您仍然可以选择使用基于iOS版本的addSubview

if #available(iOS 10.0, *) {
  collectionView.refreshControl = refreshControl
} else {
  collectionView.addSubview(refreshControl)
}

39
投票

斯威夫特4

var refreshControl: UIRefreshControl!

override func viewDidLoad() {
    super.viewDidLoad()

    refreshControl = UIRefreshControl()
    refreshControl.attributedTitle = NSAttributedString(string: "Pull to refresh")
    refreshControl.addTarget(self, action: #selector(refresh), for: .valueChanged)
    tableView.addSubview(refreshControl) 
}

@objc func refresh(_ sender: Any) {
    //  your code to refresh tableView
}

你可以停止刷新:

refreshControl.endRefreshing()

6
投票

在Swift中使用它,

如果您想在WebView中进行刷新,

所以尝试这个代码:

override func viewDidLoad() {
    super.viewDidLoad()
    addPullToRefreshToWebView()
}

func addPullToRefreshToWebView(){
    var refreshController:UIRefreshControl = UIRefreshControl()

    refreshController.bounds = CGRectMake(0, 50, refreshController.bounds.size.width, refreshController.bounds.size.height) // Change position of refresh view
    refreshController.addTarget(self, action: Selector("refreshWebView:"), forControlEvents: UIControlEvents.ValueChanged)
    refreshController.attributedTitle = NSAttributedString(string: "Pull down to refresh...")
    YourWebView.scrollView.addSubview(refreshController)

}

func refreshWebView(refresh:UIRefreshControl){
    YourWebView.reload()
    refresh.endRefreshing()
}

5
投票

安希尔的回答对我很有帮助。

然而,经过进一步的实验,我注意到建议的解决方案有时会导致一个不那么漂亮的UI glitch

相反,前往this approach *为我做了伎俩。

* Swift 2.1

//Create an instance of a UITableViewController. This will host your UITableView.
private let tableViewController = UITableViewController()

//Add tableViewController as a childViewController and set its tableView property to your UITableView.
self.addChildViewController(self.tableViewController)
self.tableViewController.tableView = self.tableView
self.refreshControl.addTarget(self, action: "refreshData:", forControlEvents: .ValueChanged)
self.tableViewController.refreshControl = self.refreshControl

2
投票

错误告诉你的是,refresh没有初始化。请注意,您选择使refresh不是可选的,在Swift中意味着它必须在调用super.init之前有一个值(或者它被隐式调用,这似乎是你的情况)。要么使refresh可选(可能是你想要的)或以某种方式初始化它。

我建议再次阅读Swift介绍性文档,其中包含了很长的内容。

最后一点,不是答案的一部分,正如@Anil所指出的那样,在iOS中有一个内置的刷新控制叫做UIRefresControl,这可能是值得研究的东西。


2
投票

我构建了一个RSS feed应用程序,其中我有一个Pull To刷新功能,最初有一些上面列出的问题。

但是为了向用户添加上面的答案,我到处寻找我的用例并找不到它。我正在从网上下载数据(RSSFeed),我想要下载我的tableView故事刷新。

上面提到的内容涵盖了正确的领域,但是由于人们遇到了一些问题,这就是我所做的,它的作用是:

我采用@Blankarsch的方法并转到我的main.storyboard并选择表视图以使用refresh,然后未提及的是创建IBOutlet和IBAction以有效地使用刷新

//Created from main.storyboard cntrl+drag refresh from left scene to assistant editor
@IBOutlet weak var refreshButton: UIRefreshControl

override func viewDidLoad() {
  ...... 
  ......
  //Include your code
  ......
  ......
  //Is the function called below, make sure to put this in your viewDidLoad 
  //method or not data will be visible when running the app
  getFeedData()
}

//Function the gets my data/parse my data from the web (if you havnt already put this in a similar function)
//remembering it returns nothing, hence return type is "-> Void"
func getFeedData() -> Void{
  .....
  .....
}

//From main.storyboard cntrl+drag to assistant editor and this time create an action instead of outlet and 
//make sure arguments are set to none and note sender
@IBAction func refresh() {
  //getting our data by calling the function which gets our data/parse our data
  getFeedData()

  //note: refreshControl doesnt need to be declared it is already initailized. Got to love xcode
  refreshControl?.endRefreshing()
}

希望这能帮助任何与我相同情况的人


2
投票
func pullToRefresh(){

    let refresh = UIRefreshControl()
    refresh.addTarget(self, action: #selector(handleTopRefresh(_:)), for: .valueChanged )
    refresh.tintColor = UIColor.appBlack
    self.tblAddressBook.addSubview(refresh)

}
@objc func handleTopRefresh(_ sender:UIRefreshControl){
    self.callAddressBookListApi(isLoaderRequired: false)
    sender.endRefreshing()
}
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