I've implemented a drag-and-drop feature on a sample project, which is a TableView with multiple sections. The interaction works fine, however, when I try to move a single row section cell near its section footer, the app crashes.
example of the interaction that causes the crash
Here is the exception the debugger throws:
Swift/Array.swift:405: Fatal error: Array index is out of range
This is the code I've written so far:
class ViewController: UIViewController {
var data = [["1"],["A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P","Q"]]
let tableView: UITableView = {
let tableView = UITableView()
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.backgroundColor = .red
tableView.rowHeight = 55
tableView.sectionFooterHeight = 50
return tableView
}()
override func viewDidLoad() {
super.viewDidLoad()
view.addSubview(tableView)
NSLayoutConstraint.activate([
tableView.topAnchor.constraint(equalTo: view.topAnchor),
tableView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
tableView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor),
])
tableView.delegate = self
tableView.dataSource = self
tableView.dragDelegate = self
tableView.dragInteractionEnabled = true
tableView.register(ShippedProductCell.self, forCellReuseIdentifier: ShippedProductCell.cellID)
}
}
extension ViewController: UITableViewDelegate, UITableViewDataSource, UITableViewDragDelegate {
func numberOfSections(in tableView: UITableView) -> Int {
return data.count
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return data[section].count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: ShippedProductCell.cellID) as! ShippedProductCell
let shippedProductData = data[indexPath.section][indexPath.row]
cell.label.text = shippedProductData
return cell
}
func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
return "Section \(section)"
}
func tableView(_ tableView: UITableView, titleForFooterInSection section: Int) -> String? {
return "Footer"
}
func tableView(_ tableView: UITableView, itemsForBeginning session: UIDragSession, at indexPath: IndexPath) -> [UIDragItem] {
guard indexPath.row != data[indexPath.section].count - 1 else { return [] }
let dragItem = UIDragItem(itemProvider: NSItemProvider())
dragItem.localObject = data[indexPath.section][indexPath.row]
return [ dragItem ]
}
func tableView(_ tableView: UITableView, moveRowAt sourceIndexPath: IndexPath, to destinationIndexPath: IndexPath) {
let mover = data[sourceIndexPath.section].remove(at: sourceIndexPath.row)
data[destinationIndexPath.section].insert(mover, at: destinationIndexPath.row)
print(data)
}
}
When doing some debugging I found that the destinationIndexPath.row was 1, but the section only has 1 row, which is out of bounds. I would really appreciate your help, thanks.
I am new at this and I heard a lot the term “custom Collectionviewcell” when looking how to make a calendar in which squares have a list of events (like google calendar), because I read I could use a custom collectionviewcell to have a tableview inside each collectionviewcell.
The thing is that I looked for it and I still don’t know what it is or how to implement it. Anyone does?
Thanks, Mateo.
What you want looks like this. But I would recommend looking at tutorials for UICollectionView and UITableView, and slowly working your way up to what you want to implement. Hopefully you can grasp the concept of this. But in theory this is how you implement a tableview inside a uicollectionviewCell.
First a class
class CollectionViewController: UICollectionViewCOntroller, UICollectionViewDelegateFlowLayout {
private let collectionViewCellIdentifier = "myCell"
override func viewDidLoad() {
super.viewDidLoad()
}
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
return 1
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: collectionViewCellIdentifier, for: indexPath) as! YourCustomCell
return cell
}
Then you want you make another Class
class YourCustomCell: UICollectionViewCell {
lazy var tableView: UITableView = {
let tv = UITableView()
tv.delegate = self
tv.dataSource = self
tv.translatesAutoresizingMaskIntoConstraints = false
return tv
}()
}
override func didMoveToSuperview() {
super.didMoveToSuperview()
NSLayoutConstraint.activate([
tableView.topAnchor.constraint(equalTo: topAnchor, constant:0 ),
tableView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0),
tableView.leftAnchor.constraint(equalTo: leftAnchor, constant:0),
tableView.rightAnchor.constraint(equalTo: rightAnchor, constant: 0)
])
}
}
and then a Extension of YOurCustumCell:
extension ReceivedCell: UITableViewDataSource {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellIdentifier, for: indexPath) as! UITableViewCell // Or perhaps a custom tableview cell class swell
return cell
}
I am trying to make a framework and I am preferring everything in code so I figured out a way to do mostly everything but the main problem I am facing is I can't put the data in my table because cellForRowAtIndexpath is not getting called.
I have set delegate and dataSource.
I have added numberOfRowsInSection and it returns 10.
I have added heightForRowAtIndexPath and it returns 10.
I have added cellForForAtIndexPath and return a cell.
The main problem is that all these other methods are called as I have added print statements in all of them except cellForForAtIndexPath.
The problem is that I can't even try debugging because the method is not even called.
class PopControl: NSObject, UITableViewDataSource, UITableViewDelegate {
let tableView = UITableView()
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("row selected")
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
print("cell for row at index path called")
let cell = UITableViewCell()
cell.textLabel?.text = "ABCD"
cell.detailTextLabel?.text = "EFGH"
return cell
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("number of rows in section called")
return 10
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
print("Height for row at index path called")
return 10
}
func makeTable(){
let vc = UIApplication.shared.keyWindow?.rootViewController?.childViewControllers.last
vc?.view.backgroundColor = UIColor.black
print(vc)
tableView.dataSource = self
tableView.delegate = self
vc?.view.addSubview(tableView)
tableView.translatesAutoresizingMaskIntoConstraints = false
tableView.topAnchor.constraint(equalTo: (vc?.view.topAnchor)!, constant: 100).isActive = true
tableView.bottomAnchor.constraint(equalTo: (vc?.view.bottomAnchor)!, constant: -20).isActive = true
tableView.leftAnchor.constraint(equalTo: (vc?.view.leftAnchor)!, constant: 20).isActive = true
tableView.rightAnchor.constraint(equalTo: (vc?.view.rightAnchor)!, constant: -20).isActive = true
print("dataSource for tableView is")
print(tableView.dataSource.debugDescription.description)
print("delegate is")
print(tableView.delegate.debugDescription.utf8CString)
}
I am using it this way because I want to call the makeTable() function from a different class. What I mean is I don't have any intention of using this class as a UIViewController or UITableViewController. I just want to use it to present the view controller with a table view from anywhere in the code.
Everything works but cellForRowAtIndexPath is not called. I mean tableView gets rendered but no cells are displayed.
The problem might be not reusing cell, try to reuse your UITableviewCell
add follow code in makeTable
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
at cellForRowAt
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
// create a new cell if needed or reuse an old one
let cell:UITableViewCell = self.tableView.dequeueReusableCell(withIdentifier:"Cell") as UITableViewCell!
// set the text from the data model
cell.textLabel?.text = "ABC"
return cell
}
I try to implement UITableView programmatically without use of xib or Storyboards. This is my code:
ViewController.swift
import UIKit
class ViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
let table: UITableViewController = MyTableViewController()
let tableView: UITableView = UITableView()
tableView.frame = CGRect(x: 10, y: 10, width: 100, height: 500)
tableView.dataSource = table
tableView.delegate = table
self.view.addSubview(tableView)
}
}
MyTableViewController.swift
import UIKit
class MyTableViewController: UITableViewController {
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
NSLog("sections")
return 2
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
NSLog("rows")
return 3
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
NSLog("get cell")
let cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "Cell")
cell.textLabel!.text = "foo"
return cell
}
}
But when I run app, all I get is empty table. In log I see a few lines of sections and rows, but no get cell. How can I fix this code to get table with 6 lines of foo text?
Note: As you mentioned you just started programming in Swift. I created a tableView programmatically. Copy and paste below code into your viewController and run the project...
import UIKit
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
private let myArray: NSArray = ["First","Second","Third"]
private var myTableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
let barHeight: CGFloat = UIApplication.shared.statusBarFrame.size.height
let displayWidth: CGFloat = self.view.frame.width
let displayHeight: CGFloat = self.view.frame.height
myTableView = UITableView(frame: CGRect(x: 0, y: barHeight, width: displayWidth, height: displayHeight - barHeight))
myTableView.register(UITableViewCell.self, forCellReuseIdentifier: "MyCell")
myTableView.dataSource = self
myTableView.delegate = self
self.view.addSubview(myTableView)
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("Num: \(indexPath.row)")
print("Value: \(myArray[indexPath.row])")
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return myArray.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "MyCell", for: indexPath as IndexPath)
cell.textLabel!.text = "\(myArray[indexPath.row])"
return cell
}
}
Output:
Updated for Swift 3
Option 1:
import UIKit
//
// MARK :- TableViewController
//
class TableViewController: UITableViewController {
private let headerId = "headerId"
private let footerId = "footerId"
private let cellId = "cellId"
//
// MARK :- HEADER
//
override func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 150
}
override func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let header = tableView.dequeueReusableHeaderFooterView(withIdentifier: headerId) as! CustomTableViewHeader
return header
}
//
// MARK :- FOOTER
//
override func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return 150
}
override func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
let footer = tableView.dequeueReusableHeaderFooterView(withIdentifier: footerId) as! CustomTableViewFooter
return footer
}
//
// MARK :- CELL
//
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 150
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath) as! CustomTableCell
return cell
}
override func viewDidLoad() {
super.viewDidLoad()
title = "TableView Demo"
view.backgroundColor = .white
setupTableView()
}
func setupTableView() {
tableView.backgroundColor = .lightGray
tableView.register(CustomTableViewHeader.self, forHeaderFooterViewReuseIdentifier: headerId)
tableView.register(CustomTableViewFooter.self, forHeaderFooterViewReuseIdentifier: footerId)
tableView.register(CustomTableCell.self, forCellReuseIdentifier: cellId)
}
}
//
// MARK :- HEADER
//
class CustomTableViewHeader: UITableViewHeaderFooterView {
override init(reuseIdentifier: String?) {
super.init(reuseIdentifier: reuseIdentifier)
contentView.backgroundColor = .orange
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
//
// MARK :- FOOTER
//
class CustomTableViewFooter: UITableViewHeaderFooterView {
override init(reuseIdentifier: String?) {
super.init(reuseIdentifier: reuseIdentifier)
contentView.backgroundColor = .green
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
//
// MARK :- CELL
//
class CustomTableCell: UITableViewCell {
override init(style: UITableViewCellStyle, reuseIdentifier: String?) {
super.init(style: style, reuseIdentifier: reuseIdentifier)
contentView.backgroundColor = .white
}
required init?(coder aDecoder: NSCoder) {
fatalError("init(coder:) has not been implemented")
}
}
Option 2: replace above Option 1 TableViewController with this class
import UIKit
//
// MARK :- ViewController
//
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
private let headerId = "headerId"
private let footerId = "footerId"
private let cellId = "cellId"
lazy var tableView: UITableView = {
let tv = UITableView(frame: .zero, style: .plain)
tv.translatesAutoresizingMaskIntoConstraints = false
tv.backgroundColor = .lightGray
tv.delegate = self
tv.dataSource = self
tv.register(CustomTableViewHeader.self, forHeaderFooterViewReuseIdentifier: self.headerId)
tv.register(CustomTableViewFooter.self, forHeaderFooterViewReuseIdentifier: self.footerId)
tv.register(CustomTableCell.self, forCellReuseIdentifier: self.cellId)
return tv
}()
//
// MARK :- HEADER
//
func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
return 150
}
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
let header = tableView.dequeueReusableHeaderFooterView(withIdentifier: headerId) as! CustomTableViewHeader
return header
}
//
// MARK :- FOOTER
//
func tableView(_ tableView: UITableView, heightForFooterInSection section: Int) -> CGFloat {
return 150
}
func tableView(_ tableView: UITableView, viewForFooterInSection section: Int) -> UIView? {
let footer = tableView.dequeueReusableHeaderFooterView(withIdentifier: footerId) as! CustomTableViewFooter
return footer
}
//
// MARK :- CELL
//
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 1
}
func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 150
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: cellId, for: indexPath) as! CustomTableCell
return cell
}
override func viewDidLoad() {
super.viewDidLoad()
title = "TableView Demo"
view.backgroundColor = .white
view.addSubview(tableView)
setupAutoLayout()
}
func setupAutoLayout() {
tableView.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
tableView.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
tableView.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
tableView.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
}
}
Swift 4 compatible
Instead of adding a UITableView to your UIViewController, you should consider creating a UITableViewController and avoid setting up delegates:
class YourTVC: TableViewController {
override func viewDidLoad() {
super.viewDidLoad()
// setup custom cells if you use them
tableView.register(CustomTableViewCell.self, forCellReuseIdentifier: "yourCell")
}
// MARK: tableView
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 3 // set to value needed
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "yourCell", for: indexPath) as! CustomTableViewCell
cell.textLabel?.text = "Cell at row \(indexPath.row)"
return cell
}
}
It makes no sense that you are using a UITableViewController as the data source and delegate for your view controller's table view. Your own view controller should be the table view's data source and delegate.
Since you seem to want a view controller with a table view that doesn't take up the entire view, move every thing to your view controller as follows:
ViewController.swift:
import UIKit
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
override func viewDidLoad() {
super.viewDidLoad()
let tableView: UITableView = UITableView()
tableView.frame = CGRect(x: 10, y: 10, width: 100, height: 500)
tableView.dataSource = self
tableView.delegate = self
self.view.addSubview(tableView)
}
func numberOfSectionsInTableView(tableView: UITableView) -> Int {
NSLog("sections")
return 2
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
NSLog("rows")
return 3
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
NSLog("get cell")
let cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "Cell")
cell.textLabel!.text = "foo"
return cell
}
}
You don't need to make a separate class for UITableView. Just in your ViewController class implement protocols of UITableViewDelegate and UITableViewDataSource and then implement delegate methods.
I think your code should be like
class ViewController: UIViewController , UITableViewDelegate , UITableViewDataSource {
override func viewDidLoad() {
super.viewDidLoad()
let table: UITableViewController = MyTableViewController()
let tableView: UITableView = UITableView()
tableView.frame = CGRect(x: 10, y: 10, width: 100, height: 500)
tableView.dataSource = table
tableView.delegate = table
self.view.addSubview(tableView)
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
NSLog("sections")
return 2
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
NSLog("rows")
return 3
}
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
NSLog("get cell")
let cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "Cell")
cell.textLabel!.text = "foo"
return cell
}
}
Tell us more info or show logs if you still face issue.
I had a similar issue in that the data would not populate for my programmatic UITableView. This was because I was using a delegate/dataSource without a strong reference. Once I kept a reference to it (I had one class implementing both UITableViewDataSource and UITableViewDelegate), the data was populated.
import UIKit
class ViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(TableCell.self, forCellReuseIdentifier: "cell")
}
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as! TableCell
cell.nameLabel.text = "TableViewCell programtically"
cell.nameLabel.textAlignment = .center
cell.nameLabel.textColor = .white
return cell
}
override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
return 100
}
}
Simple solution
import UIKit
class CustomTableViewController: UICollectionViewController {
override func viewDidLoad() {
super.viewDidLoad()
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "Cell")
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 10
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath as IndexPath)
cell.textLabel!.text = "\(indexPath.row)"
return cell
}
}
I've created UITableView programmatically, but it doesn't show any separators. When I run the project I can see on Debug View Hierarchy that it exists, but i cannot understand why i cannot see it on simulator? Any of you knows what I'm missing or what is wrong with my code?
I'll really appreciate your help.
class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
//🔵 Proerties
var tableView: UITableView!
override func viewDidLoad() {
super.viewDidLoad()
tableView = UITableView(frame: view.bounds)
tableView.autoresizingMask = [UIViewAutoresizing.FlexibleWidth, UIViewAutoresizing.FlexibleHeight]
tableView.dataSource = self
tableView.delegate = self
tableView.rowHeight = 100
tableView.separatorColor = UIColor.redColor()
tableView.separatorStyle = .SingleLine
tableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
view.addSubview(tableView)
}
// 🔵 UITableViewDataSource
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 5
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath)
let row = indexPath.row
cell.textLabel?.text = String(row)
return cell
}
// 🔵 UITableViewDelegate
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
cell.backgroundColor = UIColor.cyanColor()
}
}