ios - 如何使用字典中的值保持按钮状态

Question

我有一个 UITableView 从带有标签的字典中填充。用户可以将标签从一个 ViewController 添加到另一个 ViewController。每个标签都有一个属性 remoteID。当用户按下 + 按钮添加标签时，所选标签的按钮颜色会更改为 -。到目前为止一切正常。问题是当我从 MainViewController 返回到 TagsViewController 时，按钮的状态没有保存。现在所有标签按钮显示+。你能帮我保存按钮的状态(标题)吗？在这里，我创建了一个小项目来解决我的问题:https://github.com/tygruletz/AppendTagsToCells这是我的代码:

class Tag{

    var remoteID: Int
    var categoryID: Int
    var name: String
    var color: String
    init(remoteID: Int, categoryID: Int, name: String, color: String) {
        self.remoteID = remoteID
        self.categoryID = categoryID
        self.name = name
        self.color = color
    }
}

主VC:

class ChecklistVC: UIViewController {

    @IBOutlet weak var questionsTableView: UITableView!

    //Properties
    lazy var itemSections: [ChecklistItemSection] = {
        return ChecklistItemSection.checklistItemSections()
    }()
    var lastIndexPath: IndexPath!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(true)
        questionsTableView.reloadData()
    }
}

extension ChecklistVC: UITableViewDelegate, UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        let itemCategory = itemSections[section]
        return itemCategory.checklistItems.count
    }

    func numberOfSections(in tableView: UITableView) -> Int {

        return itemSections.count
    }

    // Set the header of each section
    func tableView(_ tableView: UITableView, titleForHeaderInSection section: Int) -> String? {

        let checklistItemCategory = itemSections[section]
        return checklistItemCategory.name.uppercased()
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {

        let cell = tableView.dequeueReusableCell(withIdentifier: "checklistCell", for: indexPath) as! ChecklistCell

        let itemCategory = itemSections[indexPath.section]
        let item = itemCategory.checklistItems[indexPath.row]
        cell.delegate = self
        cell.configCell(item)

        cell.vehicleCommentLabel.text = item.vehicleComment
        cell.trailerCommentLabel.text = item.trailerComment

        let sortedTagNames = item.vehicleTags.keys.sorted(by: {$0 < $1}).compactMap({ item.vehicleTags[$0]})

        print("Sorted tag names: \(sortedTagNames.map {$0.name})")

        let joinedTagNames = sortedTagNames.map { $0.name}.joined(separator: ", ")

        cell.tagNameLabel.text = joinedTagNames

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

        return 150
    }

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

        if segue.identifier == "goChecklistAddComment" {
            let addCommentVC = segue.destination as! ChecklistAddCommentVC
            addCommentVC.delegate = self
        }

        if segue.identifier == "goChecklistAddTag" {
            let addTagVC = segue.destination as! ChecklistAddTagVC
            addTagVC.delegate = self
            addTagVC.addedTags = itemSections[lastIndexPath.section].checklistItems[lastIndexPath.row].vehicleTags
        }
    }
}

// Receive Tags from ChecklistAddTagVC using the Delegate Pattern
extension ChecklistVC: ChecklistAddTagVCDelegate{

    func receiveAddedTags(tags: [Int : Tag]) {

        let item = self.itemSections[self.lastIndexPath.section].checklistItems[self.lastIndexPath.row]
        item.vehicleTags = tags
    }
}

标签VC:

protocol ChecklistAddTagVCDelegate {
    func receiveAddedTags(tags: [Int: Tag])
}

class ChecklistAddTagVC: UIViewController {

    // Interface Links
    @IBOutlet weak var tagsTableView: UITableView!

    // Properties
    var tagsDictionary: [Int: Tag] = [:]
    var addedTags: [Int: Tag] = [:]
    var delegate: ChecklistAddTagVCDelegate?
    var indexPathForBtn: IndexPath!

    override func viewDidLoad() {
        super.viewDidLoad()
        tagsTableView.tableFooterView = UIView()

        tagsDictionary = [
            1: Tag(remoteID: 1, categoryID: 1, name: "Tag1", color: "red"),
            2: Tag(remoteID: 2, categoryID: 1, name: "Tag2", color: "blue"),
            3: Tag(remoteID: 3, categoryID: 1, name: "Tag3", color: "orange"),
            4: Tag(remoteID: 4, categoryID: 1, name: "Tag4", color: "black")
        ]
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        print("Added tags: \(addedTags.map {$1.name})")

        setupButtons()

        tagsTableView.reloadData()
    }
}

extension ChecklistAddTagVC: UITableViewDelegate, UITableViewDataSource {

    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return tagsDictionary.count
    }

    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "defectAndDamageTagCell", for: indexPath) as! ChecklistAddTagCell
        cell.configCell()
        cell.delegate = self
        cell.tagNameLabel.text = tagsDictionary[indexPath.row + 1]?.name.capitalized
        indexPathForBtn = indexPath

        return cell
    }

    func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {

        return 60
    }
}

extension ChecklistAddTagVC: ChecklistAddTagCellDelegate{

    // When the user press Add Tag then will be added in a dictionary and sent to ChecklistVC using a callback closure.
    func addTagBtnPressed(button: UIButton, tagLabel: UILabel) {

        let buttonPosition: CGPoint = button.convert(CGPoint.zero, to: tagsTableView)
        let indexPath = tagsTableView.indexPathForRow(at: buttonPosition)
        let indexPathForBtn: Int = indexPath?.row ?? 0
        let tag: Tag = tagsDictionary[indexPathForBtn + 1] ?? Tag(remoteID: 0, categoryID: 0, name: String(), color: String())

        if button.currentTitle == "+"{
            button.setTitle("-", for: UIControl.State.normal)
            tagLabel.textColor = UIColor.orange

            // Add selected tag to Dictionary when the user press +
            addedTags[tag.remoteID] = tag
        }
        else{
            button.setTitle("+", for: UIControl.State.normal)
            tagLabel.textColor = UIColor.black

            // Delete selected tag from Dictionary when the user press -
            addedTags.removeValue(forKey: tag.remoteID)
        }
        // Send the Dictionary to ChecklistVC
        if delegate != nil{
            delegate?.receiveAddedTags(tags: addedTags)
        }
        print("\n ****** UPDATED DICTIONARY ******")
        print(addedTags.map {"key: \($1.remoteID) - name: \($1.name)"})
    }

    // Setup the state of the buttons and also the color of the buttons to be orange if that Tag exist in `addedTags` dictionary.
    func setupButtons(){

        for eachAddedTag in addedTags {

            if eachAddedTag.value.remoteID == tagsDictionary[1]?.remoteID {

                print(eachAddedTag)
            }
        }
    }
}

这是我的错误捕获:

感谢您正在阅读本文!

Answer 1

首先你需要一个数组而不是字典

tagsArr = [
        Tag(remoteID: 1, categoryID: 1, name: "Tag1", color: "red"),
        Tag(remoteID: 2, categoryID: 1, name: "Tag2", color: "blue"),
        Tag(remoteID: 3, categoryID: 1, name: "Tag3", color: "orange"),
        Tag(remoteID: 4, categoryID: 1, name: "Tag4", color: "black")
    ]

然后 vehicleTags propety 应该是 [Tag]() ，知道它是否存在使用 ChecklistAddTagVC 的 cellForRowAt 里面

let tag = tagsArr[indexPath.row].remoteID
let res = addedTags.map { $0.remoteID }

if  res.contains(tag) { 
   // tag exists color it 
}
else { 
   // not here
}