我正在使用swift构建一个RSS阅读器，需要实现重新加载功能。
以下是我如何努力做到这一点。
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()
}
我得到:
财产的自我。刷新'未在super初始化。init调用
请帮助我理解手势识别器的行为。一个工作样例代码将是一个很大的帮助。
谢谢。
细节
Xcode版本10.3 (10G8)， Swift 5
特性
能够使“拉刷新”编程
保护从多个“拉刷新”事件
当视图控制器切换(例如在TabController的情况下)时，继续动画活动指示器的能力
解决方案
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) }
}
使用
// 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()
完整的样品
不要忘记在这里添加解决方案代码
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()
}
}
这就是我如何使用Xcode 7.2让它工作的，我认为这是一个主要的错误。我在我的UITableViewController中使用它在viewWillAppear中
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，我必须在设置我的UIRefreshControl之后调用configureMessage()方法，随后的刷新将正常工作。
对于拉刷新，我正在使用
DGElasticPullToRefresh
https://github.com/gontovnik/DGElasticPullToRefresh
安装
豆荚的DGElasticPullToRefresh
import DGElasticPullToRefresh
然后把这个函数放到你的swift文件中，然后从你的
override 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!)
}
不要忘记在视图消失时删除引用
要删除拉刷新，请将此代码放入您的
重写func viewDidDisappear(_ animated: Bool)
override func viewDidDisappear(_ animated: Bool) {
table.dg_removePullToRefresh()
}
看起来就像
快乐编码:)
你可以使用tableView的子类:
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 -在接口构建器改变类你的tableView PullToRefreshTableView或创建一个PullToRefreshTableView编程
在你的视图控制器中实现PullToRefreshTableViewDelegate
当表视图开始刷新时，tableViewDidStartRefreshing(tableView: PullToRefreshTableView)将在视图控制器中被调用
4 -调用yourTableView.endRefreshing()来完成刷新
