CODEWITHSUNDEEP
swiftuitableview
magellan5
magellan5

Reputation: 37

Get First Letter of Each Element in Two Dimensional Array for Header Section & Adjust Header Height

I am trying to get the first letter of the first element in a two dimensional array to add as a header for my tableview. The code is below:

    var cityArray = [["NYC, NY", New Hampshire"],["Buffalo, NY]]

    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
    let label = UILabel()
    label.backgroundColor = UIColor.flatOrangeColorDark()
    label.textColor = .white
    if searching {
    } else {
            let headerArray = cityArray.compactMap{$0.first?.prefix(1)}
            print("\(headerArray)")
            for i in headerArray {
                label.text = String(i)
                //This returns for all of the headers the last element in headerArray
            }
        } 
    return label
    }

This returns "B" for all headers

Additionally, I would like to make the headers disappear when scrolling. This was achieved by selecting the tableview as grouped. However, this makes each cell the same height. I would like to make the header smaller in height than the other cells. Here is the code currently:

 var tableHeaderHeight = 45

 func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    if searching {
    return 0
    } else {
        return CGFloat(tableHeaderHeight)
    }
  }  

 override func viewDidLoad() {
 super.viewDidLoad()
 cityTableview.rowHeight = 75
 //need to create a dynamic height for the section
 //alternatively using .automaticdimension = true
  }

Upvotes: 0

Views: 155

Answers (1)

Programmer54
Programmer54

Reputation: 171

The line

var cityArray = [["NYC, NY", New Hampshire"],["Buffalo, NY]]

will not compile due to the missing quotes. I am not sure how your array should exactly look like, but I assume it can be

var cityArray = [["NYC, NY", "New Hampshire"],["Buffalo", "NY"]]

Then you can use a map function to get the first element using first and the first letter using prefix:

let filteredArray = cityArray.map({$0.first?.prefix(1)})
for firstLetter in filteredArray {
    if let uFirstLetter = firstLetter {
       print(uFirstLetter) // prints N B
    }
}

Update: this is a minimum working example which will give you N in the first header and B in the second header:

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    
    var cityArray = [["NYC, NY", "New Hampshire"],["Buffalo", "NY"]]
    var filteredArray: [String.SubSequence?] = []
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return 1 //just for simplification purpose, change it according to your needs
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        //just for simplification purpose, change it according to your needs
        let cell = UITableViewCell()
        return cell
    }
    
    
    override func viewDidLoad() {
        super.viewDidLoad()
        let tableView = UITableView()
        tableView.delegate = self
        tableView.dataSource = self
        tableView.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(tableView)
        tableView.widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
        tableView.heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
        
        filteredArray = cityArray.map({$0.first?.prefix(1)})
    }
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return cityArray.count
    }
    
    func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
        let label = UILabel()
        label.backgroundColor = .lightGray
        label.textColor = .red
        if let uFirstLetter = filteredArray[section] {
            label.text = uFirstLetter.description
            return label
        } else {
            return nil
        }
    }
}

Upvotes: 1

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