swift: tableview does not work after reloadData - ios

i have a tableview in a viewcontroller and because i need to reuse most of the code for another table i created an extra class:
class StatisticsViewDelegate: NSObject, UITableViewDelegate, UITableViewDataSource {
var defaultList:[String]
var infolist:[String] = []
var tableView:UITableView
var controller:UIViewController?
init(defaultList:[String], view:UITableView, controller:UIViewController?) {
self.defaultList = defaultList
self.controller = controller
tableView = view
super.init()
tableView.delegate = self
tableView.dataSource = self
loadTable()
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return infolist.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "infocell", for: indexPath) as! TableViewCell
// [fill cell]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
// [...]
}
func loadTable() {
DispatchQueue.global(qos: .userInitiated).async {
//[...]
// in this case:
self.infolist = self.defaultList
DispatchQueue.main.async {
self.tableView.reloadData()
}
}
}
}
and in my UITViewController in the viewDidLoad():
delegate = StatisticsViewDelegate(defaultList: defaultList, view: tableView, controller:self)
delegate is a member of the ViewController
now when i run it, the function func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) never gets called. The func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) gets called however(before and after the reload) and returns the correct number(in my case 4). The TableView isn't visible at all. Where is my error?

Maybe you can use the subclassing strategy to resolve your problem. There are many reference passed to your class and if you forgot to clean that up you will be have memory leaks in your hand. So I'll suggest the simple example as below. You can modify as you like and let me know if that was what you are after. If not please pardon me.
//This will be parent class that will handle all table methods, so you need to write only once the delegates and stuffs
class MyCommonTableController: UITableViewController {
var infoList = [String]()
// MARK: - TableView Delegate and Datsource Impl
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return infoList.count
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 55.0
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath)
cell.textLabel?.text = infoList[indexPath.row]
return cell
}
}
The first class that is directly subclassing the from above MyCommonTableController
//In here we just have to know the data and set the infoList from parent
class TheTableViewController: MyCommonTableController {
let defaultList = ["Data1","Data2","Data3"] //....etc
override func viewDidLoad() {
super.viewDidLoad()
//this is were I will set those
infoList = defaultList
//reload the table
tableView.reloadData()
}
}
The second class that is directly subclassing the from above MyCommonTableController. Same process goes here
class TheSecondTableViewController: MyCommonTableController {
let defaultList = ["List1","List2","List3"] //....etc
override func viewDidLoad() {
super.viewDidLoad()
//this is were I will set those
infoList = defaultList
//reload the table
tableView.reloadData()
}
}
And now you are not repeating and table methods. You can also get the reference of table and use in your norma table view
#IBOutlet weak var theTable: UITableView!
let defaultList = ["List1","List2","List3"] //....etc
let commonTable = MyCommonTableController()
// MARK: - LifeCycle
override func viewDidLoad() {
super.viewDidLoad()
commonTable.infoList = defaultList
commonTable.tableView = theTable
}

Related

UITableViewCell with unwanted extra objects when scrolling down

I have a view controller, in the viewdidload method I call a function to make some calls to retrieve data online.
After I retrieve the data I append them into an array and reload the table view
at first, everything looks great however, when I scroll down I get to see what you see down below.
extension CastTableViewController : UITableViewDelegate, UITableViewDataSource {
func conigure_cast_table () {
castTable.translatesAutoresizingMaskIntoConstraints = false
castTable.delegate = self
castTable.dataSource = self
castTable.register(ActorCell.self, forCellReuseIdentifier: ActorCell.cellid)
view.addSubview(castTable)
castTable.frame = view.bounds
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return cast.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = castTable.dequeueReusableCell(withIdentifier: ActorCell.cellid, for: indexPath) as! ActorCell
let name = cast[indexPath.row].name
let character_name = cast[indexPath.row].character
let pic = cast[indexPath.row].picture_path
cell.configure(name: name, charName: character_name, pic_url: pic)
return cell
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 100
}
}
i fixed this by using prepareforreuse
// in the custom cell class
override func prepareForReuse() {
super.prepareForReuse()
for subview in stack.arrangedSubviews {
stack.removeArrangedSubview(subview)
}
actorPic.image = nil
realName.banner_title.text = nil
realName.info.text = nil
character.banner_title.text = nil
character.info.text = nil
}

tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) not getting called in UITableViewController subclass

numberOfSection and numberOfRowsInSection of UITableViewController is getting called but cellForRow not. What could be the reason ? Below is the code for tableViewController.
class GlobalSearchTableViewController: UITableViewController {
/// MARK: Properties
/// Delegate
weak var delegate: GlobalSearchTableViewControllerDelegate?
private var state = GlobalSearchTableState(searchResults: [])
override func viewDidLoad() {
super.viewDidLoad()
tableView.estimatedSectionFooterHeight = 60
tableView.sectionFooterHeight = UITableView.automaticDimension
tableView.estimatedRowHeight = 60
tableView.rowHeight = UITableView.automaticDimension
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 2
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
return UITableViewCell()
}
extension GlobalSearchTableViewController: GlobalSearchTablePresenter {
func present(state: GlobalSearchTableState) {
tableView.reloadData()
}
try to return cell
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell : UITableViewCell!
cell = tableView.dequeueReusableCell(withIdentifier: "cell")
cell.textLabel?.text = dataArray[indexPath.row]
return cell
}
Try adding tableView.delegate = self or tableView.dataSource = self.

Getting an input onclick in UITableView

I'm trying to get an input when the user taps on a cell of a UITableView. That's my code:
import UIKit
class TableView: UIViewController, UITableViewDataSource {
public var data = Array<Array<String>>()
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cellIdentifier")!
cell.textLabel?.text = data[indexPath.row][0]
cell.detailTextLabel?.text = data[indexPath.row][1]
return cell
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("TEST")
}
}
And in ViewController I have:
...
let tvClass = TableView()
override func viewDidLoad() {
super.viewDidLoad()
tvClass.data = [["title", "name"]]
self.tableView.dataSource = tv
self.tableView.alwaysBounceVertical = false
}
...
Why am I not getting "TEST" when I click on a cell?
didSelectRowAt is a method inside UITableViewDelegate so , set table delegate like this in viewDidLoad
self.tableView.delegate = self;
and change class declaration like this
class TableView: UIViewController, UITableViewDataSource , UITableViewDelegate {
The Only missing thing is
TableViewDelegate.
As delegate tells iOS sdk to know that action is being performed.
self.tableView.delegate = self

Swift 3.0 Textfield in a TableViewCell not showing up

I am trying to display a textfield on a tableview using a custom cell. I think I have set up the delegation protocol properly, but when loaded, the tableview doesn't show the textfield. I have added a textfield into the customcell, set the class to CustomCell, and changed the identifier to "Cell", but I am not sure what else I am missing.
view controller with tableview:
#IBOutlet weak var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableView.delegate = self
tableView.dataSource = self
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("Hello")
}
func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! CustomCell
cell.cellDelegate = self
cell.contentView.bringSubview(toFront: cell.textField)
cell.textField.delegate = self as? UITextFieldDelegate
cell.textField.text = "Test"
return cell
}
func didPressTextField(indexPath: IndexPath) {
print("textfield was tapped")
}
custom cell VC:
protocol CustomCellDelegate : class {
func didPressTextField(indexPath: IndexPath)
}
class CustomCell: UITableViewCell {
weak var cellDelegate: CustomCellDelegate?
var indexPath: IndexPath!
override func awakeFromNib() {
super.awakeFromNib()
self.cellDelegate = nil
// Initialization code
}
#IBOutlet weak var textField: UITextField!
#IBAction func textFieldWasTapped(_ sender: UITextField) {
self.cellDelegate?.didPressTextField(indexPath: indexPath)
}
Your data source is empty.
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// data is not containing any value
return data.count
}
Check data.count it should have some data and also if that is custom cell with XIB then you need to register cell in view didload
self.tableView.register(UINib(nibName: "Your Cell XIB name", bundle: nil),
forCellWithReuseIdentifier: "Cell")
Check your data.count. it must return value greater than 0 otherwise your tableView is showing with 0 rows and nothing is display in tableView.
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// debug at this point check what is value of data.count its must be greater than 0
return data.count
}

UITableView delegate using extensions swift

This is a fairly simple question I think. I've separated my UITableView delegate / data sources into their own extensions
//MARK: - UITableView Data Source/Delegate
extension TweetsViewController: UITableViewDataSource {
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 0
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! TweetCell
return cell
}
}
However in the view controller itself I need to set the tblView delegate
class TweetsViewController : UIViewController {
#IBOutlet weak var tblView: UITableView!
var fetchedResultsController : NSFetchedResultsController!
//MARK: View Management
override func viewDidLoad() {
super.viewDidLoad()
tblView.dataSource = self
}
}
However, since the view controller is nor conforming to the protocols but having the extensions handle them, then how do I explicitly set the datasource and delegate for the tableView? Thanks!
You can divide in a extension, as you can check in the apple documentation section about Extensions handling Protocols.
Here I have implement a minimum code doing what you ask, check it out.
import UIKit
class TableViewViewController: UIViewController {
#IBOutlet weak var table: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
table.delegate = self
table.dataSource = self
}
}
extension TableViewViewController: UITableViewDelegate,UITableViewDataSource {
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath)
cell.textLabel!.text = "it works"
return cell
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
}
In Swift 3 and above the table view datasource and delegate methods changed.
import UIKit
class HomeViewController: UIViewController {
#IBOutlet var tblPropertyList: UITableView!
// MARK: - View Life Cycle
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
tblPropertyList.delegate = self
tblPropertyList.dataSource = self
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
// MARK: - Table View DataSource
extension HomeViewController: UITableViewDataSource {
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath as IndexPath)
cell.textLabel!.text = "\(indexPath.row) - Its working"
return cell
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 2
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 2
}
}
// MARK: - Table View Delegate
extension HomeViewController: UITableViewDelegate {
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let indexPath = tableView.indexPathForSelectedRow
let currentCell = tableView.cellForRow(at: indexPath!)!
print(currentCell.textLabel!.text!)
}
}
the view controller is nor conforming to the protocols but having the extensions handle them
This is incorrect. The extension makes the view controller conformant to the protocols, and the data source and delegate can be set as usual, e.g.: self.tableView.delegate = self
Now in Swift 5.1 you don't need to inherit UITableViewDelegate and UITableViewDataSource
extension HomeViewController {
// MARK: - Table View DataSource
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "reuseIdentifier", for: indexPath as IndexPath)
cell.textLabel!.text = "\(indexPath.row) - Its working"
return cell
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 2
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 2
}
}
// MARK: - Table View Delegate
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let indexPath = tableView.indexPathForSelectedRow
let currentCell = tableView.cellForRow(at: indexPath!)!
print(currentCell.textLabel!.text!)
}
}

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