[iOS] UITableView의 생성, cell 삭제

simple Test Project 작성

 

 

 

 

 

import UIKit

class TestViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    
    var korean: [String] = ["가", "나", "다" ]
    var english: [String] = ["A", "B", "C" ]
    
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return 2
    }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return section == 0 ? korean.count : english.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // 셀 재사용
        let cell: UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        // 셀에 무엇을 표시할 것인가?
        var text: String{
            return indexPath.section == 0 ? korean[indexPath.row] : english[indexPath.row]
        }
        cell.textLabel?.text = text
        return cell
    }
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
        return section == 0 ? "한글" : "영어"
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }
}

1. cell의 Identifier기입

2. ViewController에 datasourse, delegate 대입, 코드에도 참조 추가

3. protocol 준수.

• func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell (셀 재사용, 셀에 무엇을 표현할 것인가?)

• func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int (각 섹션에 몇 개의 row를 띄울 것인가)

 

 

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• UITableViewCell Style 종류

• NSIndexPath란?

UIKit에서는 NSIndexPath에 두 개의 값을 지정.

- 지정된 Path의 section 번호

   :  var section: Int / indexPath.section 형태로 코드에서 사용

- 지정된 Path의 row 번호 (특정 section에 속한 row) 

   :  var row: Int / indexPath.row 형태로 코드에서 사용

 

 

• 셀 재사용 방식?

let cell: UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)

cell indentifier를 사용해 dequeueReusableCell을 하는 방식

-> Table에서 사용하는 각 cell은 heap에서 할당되고, 더 이상 사용되지 않는 cell은 heap에 반환된다

     Table이 새로운 cell을 위한 공간을 찾을 때, heap에 같은 identifier인 cell이 있으면 이를 재활용한다

 

* 자료구조 다시 공부 필요

 

 

---

depth가 있는 table view

top page

bottom page

// top ViewController

import UIKit

class TestViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {
    @IBOutlet weak var table: UITableView!
    
//    var korean: [String] = ["가", "나", "다" ]
//    var english: [String] = ["A", "B", "C" ]
    
    // Dictionary로 Dept 구현
    var lang: [String : [String]] = ["Korean":["가", "나", "다"], "English" : ["A", "B", "C"]]
    
    
//    func numberOfSections(in tableView: UITableView) -> Int {
//        return lang.keys.count
//    }
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return lang.count
        //return section == 0 ? korean.count : english.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        // 셀 재사용
        let cell: UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath)
        // 셀에 무엇을 표시할 것인가?
        
//        var text: String{
//            return indexPath.section == 0 ? korean[indexPath.row] : english[indexPath.row]
//        }
        var arr: Array = Array(lang.keys)
        cell.textLabel?.text = arr[indexPath.row]
        return cell
    }
//    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {
//        return section == 0 ? "한글" : "영어"
//    }

    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.
    }
    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "dept" {
            if let destination = segue.destination as? TableViewController{
                if let selectedIndex = self.table.indexPathsForSelectedRows?.first?.row{
                    destination.title = Array(lang.keys)[selectedIndex]
                    destination.detailList = Array(lang.values)[selectedIndex]
                }
            }
        }
    }
    func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }
    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete{
            let name = Array(lang.keys)[indexPath.row]
            self.lang.removeValue(forKey: name)
            
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
//        else if editingStyle == .insert{
//
//        }
    }
}

// bottom TableViewContoller

import UIKit

class TableViewController: UITableViewController {

    // force optional unwrapping하지 않으면 오류남
    var detailList: [String]!
    override func viewDidLoad() {
        super.viewDidLoad()

        self.navigationItem.rightBarButtonItem = self.editButtonItem
    }

    // MARK: - Table view data source

    override func numberOfSections(in tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return detailList.count
    }

    
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell: UITableViewCell = tableView.dequeueReusableCell(withIdentifier: "detailCell", for: indexPath)

        cell.textLabel?.text = detailList[indexPath.row]
        
        // Configure the cell...

        return cell
    }
    

    
    // Override to support conditional editing of the table view.
    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }
    

    // Override to support editing the table view.
    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // Delete the row from the data source
            let name = Array(detailList)
            tableView.deleteRows(at: [indexPath], with: .fade)
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }    
    }
   
}

 

 

두가지 삭제 방식

* 필수 : 셀 삭제시 필요한 코드 ( 데이터와 셀 모두 삭제)

    override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            // Delete the row from the data source
            let name = Array(detailList)
            tableView.deleteRows(at: [indexPath], with: .fade)
        } else if editingStyle == .insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }    
    }

 

 

1. edit 버튼 추가

self.navigationItem.rightBarButtonItem = self.editButtonItem

TableViewController에서만 사용 가능!! (ViewController에서 사용하려면 따로 barbuttonItem 추가 후 메서드 직접 구현해야함)

 

 

2. slider

모든 경우 사용 가능. 필수 코드만 구현해도 사용할 수 있음. 

 

 

-> ViewContoller에서는 슬라이더만(따로 버튼을 만들어 구현하지 않을 시), TableViewController에서는 둘 다 가능함!

 

 

 

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Error

1. 'unable to dequeue a cell with identifier detailCell - must register a nib or a class for the identifier or connect a prototype cell in a storyboard'

- cell의 identifier 설정 오류. 

 

Restoration ID 가 아님!!

Identifier에 정확히 표기했는지 확인

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자료 출처 : www.boostcourse.org/mo326