我有两个完全相同的类，在用户的位置附近加载所选类别的位置但是一个使用collectionView而另一个使用tableView（和特定的动画）。
我只添加了提供问题的代码部分，虽然有些名称不同，但故事板和其他类的所有链接都是相同的，您可以看到这两个类之间的代码非常相似。
我的问题是带有collectionView的类工作得很好，但是使用tableView的类没有显示tableView的单元格（就好像它没有正确加载它）如果有人能看到是否有错误，我会不胜感激。
这是使用collectionView的类：
import UIKit
import CoreLocation
import AVFoundation
private let reuseIdentifier = "PlacesCell"
extension UIViewController {
func present(viewController : UIViewController, completion : (() -> ())? = nil ){
if let presented = self.presentedViewController {
presented.removeFromParentViewController()
}
self.present(viewController, animated: true, completion: completion)
}
}
class NearbyPlacesViewController: UICollectionViewController, UICollectionViewDelegateFlowLayout {
var locationManager:CLLocationManager?
let minimumSpacing : CGFloat = 15 //CGFloat(MAXFLOAT)
let cellWidth: CGFloat = 250
let radius = 5000 // 5km
var category : QCategory?
var currentLocation : CLLocationCoordinate2D?
var places: [QPlace] = []
var isLoading = false
var response : QNearbyPlacesResponse?
override func viewDidLoad() {
super.viewDidLoad()
//self.collectionView
self.title = category?.name
collectionView?.contentInset = UIEdgeInsets.init(top: 0, left: minimumSpacing, bottom: 0, right: minimumSpacing)
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
determineMyCurrentLocation()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillAppear(animated)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
category?.markView()
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func canLoadMore() -> Bool {
if isLoading {
return false
}
if let response = self.response {
if (!response.canLoadMore()) {
return false
}
}
return true
}
func loadPlaces(_ force:Bool) {
if !force {
if !canLoadMore() {
return
}
}
print("load more")
isLoading = true
NearbyPlacesController.getNearbyPlaces(by: category?.name ?? "food", coordinates: currentLocation!, radius: radius, token: self.response?.nextPageToken, completion: didReceiveResponse)
}
func didReceiveResponse(response:QNearbyPlacesResponse?, error : Error?) -> Void {
if let error = error {
let alertController = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
let actionDismiss = UIAlertAction(title: "Dismiss", style: .cancel, handler: nil)
let actionRetry = UIAlertAction(title: "Retry", style: .default, handler: { (action) in
DispatchQueue.main.async {
self.loadPlaces(true)
}
})
alertController.addAction(actionRetry)
alertController.addAction(actionDismiss)
DispatchQueue.main.async {
self.present(viewController: alertController)
}
}
if let response = response {
self.response = response
if response.status == "OK" {
if let placesDownloaded = response.places {
places.append(contentsOf: placesDownloaded)
}
self.collectionView?.reloadData()
} else {
let alert = UIAlertController.init(title: "Error", message: response.status, preferredStyle: .alert)
alert.addAction(UIAlertAction.init(title: "Cancel", style: .cancel, handler: nil))
alert.addAction(UIAlertAction.init(title: "Retry", style: .default, handler: { (action) in
DispatchQueue.main.async {
self.loadPlaces(true)
}
}))
self.present(viewController: alert)
}
isLoading = false
}
else {
print("response is nil")
}
}
// MARK: UICollectionViewDataSource
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return places.count
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! PlacesCell
let place = places[indexPath.row]
cell.update(place: place)
if indexPath.row == places.count - 1 {
loadPlaces(false)
}
return cell
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
performSegue(withIdentifier: "maps-vc", sender: indexPath)
}
// MARK: UICollectionViewDelegateFlowLayoutDelegate
public func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumInteritemSpacingForSectionAt section: Int) -> CGFloat {
return minimumSpacing
}
func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
let cellPadding: CGFloat = 20.0
let columnWidth:CGFloat = cellWidth
let imageWidth = columnWidth
let labelWidth = columnWidth - cellPadding * 2
let photoHeight = heightForPhotoAtIndexPath(indexPath: indexPath, withWidth: imageWidth)
let annotationHeight = heightForAnnotationAtIndexPath(indexPath: indexPath, withWidth: labelWidth)
let height = photoHeight + annotationHeight
return CGSize.init(width: columnWidth, height: height)
}
// Calculates the height of photo
func heightForPhotoAtIndexPath(indexPath: IndexPath,
withWidth width: CGFloat) -> CGFloat {
var size = CGSize.init(width: CGFloat(MAXFLOAT), height: 1)
let place = places[indexPath.row]
guard let photo = place.photos?.first, place.photos?.first?.photoRef != nil else {
return 0
}
size = CGSize.init(width: CGFloat(photo.width!), height: CGFloat(photo.height!))
let boundingRect = CGRect(x: 0, y: 0, width: width, height: CGFloat(MAXFLOAT))
let rect = AVMakeRect(aspectRatio: size, insideRect: boundingRect)
return rect.size.height
}
// Calculates the height label
func heightForAnnotationAtIndexPath(indexPath: IndexPath, withWidth width: CGFloat) -> CGFloat {
let place = places[indexPath.row]
let annotationPadding = CGFloat(5)
let font = UIFont.systemFont(ofSize: 15)
let commentHeight = place.heightForComment(font, width: width)
let height = annotationPadding + commentHeight + annotationPadding
return height
}
// did receive location
func didReceiveUserLocation(_ userLocation:CLLocation) {
currentLocation = userLocation.coordinate
loadPlaces(true)
}
// MARK: - Navigation
// In a storyboard-based application, you will often want to do a little preparation before navigation
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "maps-vc" && sender is IndexPath {
let dvc = segue.destination as! MapViewController
dvc.index = (sender as! IndexPath).row
dvc.places = places
dvc.userLocation = currentLocation
}
}
}
这是使用tableView的类：
import UIKit
import MapKit
import CoreLocation
import GoogleMaps
import GooglePlaces
import Social
import AVFoundation
private let resueIdentifier = "MyTableViewCell"
extension UIViewController {
func present(viewController : UIViewController, completion : (() -> ())? = nil ){
if let presented = self.presentedViewController {
presented.dismiss(animated: true, completion: {
self.present(viewController, animated: true, completion: completion)
})
} else {
self.present(viewController, animated: true, completion: completion)
}
}
}
class CourseClass2: UIViewController, UITableViewDelegate, UITableViewDataSource {
@IBOutlet weak var tableView: UITableView!
var locationManager:CLLocationManager?
let minimumSpacing : CGFloat = 15 //CGFloat(MAXFLOAT)
let cellWidth: CGFloat = 250
let radius = 5000 // 5km
var category : QCategoryy?
var currentLocation : CLLocationCoordinate2D?
var places: [QPlace] = []
var isLoading = false
var response : QNearbyPlacesResponse?
var rows = 0
override func viewDidLoad() {
super.viewDidLoad()
self.title = category?.name
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
determineMyCurrentLocation()
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillAppear(animated)
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
rows = 0
insertRowsMode3()
tableView.reloadData()
category?.markView()
}
@IBAction func refreshTapped(_ sender: Any) {
rows = 0
insertRowsMode3()
tableView.reloadData()
}
func canLoadMore() -> Bool {
if isLoading {
return false
}
if let response = self.response {
if (!response.canLoadMore()) {
return false
}
}
return true
}
func loadPlaces(_ force:Bool) {
if !force {
if !canLoadMore() {
return
}
}
print("load more")
isLoading = true
NearbyPlaces.getNearbyPlaces(by: category?.name ?? "food", coordinates: currentLocation!, radius: radius, token: self.response?.nextPageToken, completion: didReceiveResponse)
}
func didReceiveResponse(response:QNearbyPlacesResponse?, error : Error?) -> Void {
if let error = error {
let alertController = UIAlertController(title: "Error", message: error.localizedDescription, preferredStyle: .alert)
let actionDismiss = UIAlertAction(title: "Dismiss", style: .cancel, handler: nil)
let actionRetry = UIAlertAction(title: "Retry", style: .default, handler: { (action) in
DispatchQueue.main.async {
self.loadPlaces(true)
}
})
alertController.addAction(actionRetry)
alertController.addAction(actionDismiss)
DispatchQueue.main.async {
self.present(viewController: alertController)
}
}
if let response = response {
self.response = response
if response.status == "OK" {
if let placesDownloaded = response.places {
places.append(contentsOf: placesDownloaded)
}
self.tableView?.reloadData()
} else {
let alert = UIAlertController.init(title: "Error", message: response.status, preferredStyle: .alert)
alert.addAction(UIAlertAction.init(title: "Cancel", style: .cancel, handler: nil))
alert.addAction(UIAlertAction.init(title: "Retry", style: .default, handler: { (action) in
DispatchQueue.main.async {
self.loadPlaces(true)
}
}))
self.present(viewController: alert)
}
isLoading = false
}
else {
print("response is nil")
}
}
func insertRowsMode2() {
tableView.beginUpdates()
for i in 0..<places.count {
insertRowMode2(ind: i, usr: places[i])
}
tableView.endUpdates()
}
func insertRowMode2(ind:Int,usr:QPlace) {
tableView.beginUpdates()
let indPath = IndexPath(row: ind, section: 0)
rows = ind + 1
tableView.insertRows(at: [indPath], with: .right)
tableView.endUpdates()
}
func insertRowsMode3() {
tableView.beginUpdates()
rows = 0
insertRowMode3(ind: 0)
tableView.endUpdates()
}
func insertRowMode3(ind:Int) {
tableView.beginUpdates()
let indPath = IndexPath(row: ind, section: 0)
rows = ind + 1
tableView.insertRows(at: [indPath], with: .right)
guard ind < places.count-1 else { return }
DispatchQueue.main.asyncAfter(deadline: .now()+0.20) {
self.insertRowMode3(ind: ind+1)
}
tableView.endUpdates()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return places.count /* rows */
}
public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! MyTableViewCell
let place = places[indexPath.row]
cell.update(place: place)
if indexPath.row == places.count - 1 {
loadPlaces(false)
}
return (cell)
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
tableView.deselectRow(at: indexPath, animated: true)
UIView.animate(withDuration: 0.2, animations: {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! MyTableViewCell
})
performSegue(withIdentifier: "goToLast" , sender: indexPath.row)
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 100
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCellEditingStyle.delete {
places.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
}
}
func didReceiveUserLocation(_ userLocation:CLLocation) {
currentLocation = userLocation.coordinate
loadPlaces(true)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
if segue.identifier == "goToLast" && sender is IndexPath {
let dvc = segue.destination as! FinalClass
dvc.index = (sender as! IndexPath).row
dvc.places = places
dvc.userLocation = currentLocation
}
}
@IBAction func IndTapped(_ sender: Any) {
dismiss(animated: true, completion: nil)
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
答案 0 :(得分：0)
您是否将CourseClass2类设置为tableView的委托/ dataSource？
尝试添加
tableView.dataSource = self
tableView.delegate = self
到你的viewDidLoad方法。
几乎每次遇到像你这样的问题都是因为我忘了设置委托或dataSource。
编辑：我以前只在答案中添加了代表，感谢Dennis提醒我dataSource。
答案 1 :(得分：0)
我看到你正在进行异步更新，但同步的reloadData ......
您必须在asyncAfter中进行更新，或者在该闭包中为insertRowMode3和reloadData添加一个闭包......
你可以尝试一下吗？
func insertRowMode3(ind:Int) {
DispatchQueue.main.asyncAfter(deadline: .now()+0.20) {
tableView.reloadData()
}
}