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。
我建议在每个类中使用pull to Refresh的扩展。
1)创建一个空的swift文件:文件-新建-文件- swift文件。
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)在你的视图控制器中调用这些方法:
override func viewWillAppear(animated: Bool) {
self.makePullToRefreshToTableView(bidderListTable, triggerToMethodName: "pullToRefreshBidderTable")
}
4)在某些时候,你想要结束刷新:
func pullToRefreshBidderTable() {
self.makePullToRefreshEndRefreshing("bidderListTable")
//Code What to do here.
}
OR
self.makePullToRefreshEndRefreshing("bidderListTable")
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:)
UIRefreshControl直接支持在每个UICollectionView, UITableView和UIScrollView(需要iOS 10+)!
这些视图中的每一个都有一个refreshControl实例属性,这意味着不再需要在你的滚动视图中添加它作为子视图,你所要做的就是:
@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
}
@objc func doSomething(refreshControl: UIRefreshControl) {
print("Hello World!")
// somewhere in your code you might need to call:
refreshControl.endRefreshing()
}
就我个人而言,我觉得将它作为滚动视图的属性比将它作为子视图添加更自然,特别是因为唯一合适的视图作为UIRefreshControl的父视图是一个滚动视图,即使用UIRefreshControl的功能只在与滚动视图一起工作时有用;这就是为什么这种方法应该更明显地设置刷新控件视图。
但是,你仍然可以选择基于iOS版本使用addSubview:
if #available(iOS 10.0, *) {
collectionView.refreshControl = refreshControl
} else {
collectionView.addSubview(refreshControl)
}
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()
}
}