Question

我有这个tableviewcontroller和detailviewcontroller，它有一个文本字段，当用户点击tableviewcell时，它会转到文本字段，用户可以编辑内容!! 如何通过后退按钮在文本字段中使用新内容更新表格视图？

let sectionTitles = ["ongoing","Done"]
var list = [String]()

class MasterViewController: UITableViewController {

    var detailViewController: DetailViewController? = nil
    var objects = sectionTitles.map({_ in return [Any]()})

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        navigationItem.leftBarButtonItem = editButtonItem

        let addButton = UIBarButtonItem(barButtonSystemItem: .add, target: self, action: #selector(insertNewObject(_:)))
        navigationItem.rightBarButtonItem = addButton

        if let split = splitViewController {
            let controllers = split.viewControllers
            detailViewController = (controllers[controllers.count-1] as! UINavigationController).topViewController as? DetailViewController
        }
    }

    @objc
    func insertNewObject(_ sender: Any) {
        objects[0].insert("Task 1", at: 0)
        let indexPath = IndexPath(row: 0, section: 0)
        tableView.insertRows(at: [indexPath], with: .automatic)
    }

    // MARK: - Segues

    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if segue.identifier == "showDetail" {
            if let indexPath = tableView.indexPathForSelectedRow {
                let object = objects[indexPath.section][indexPath.row] as! String
                let controller = (segue.destination as! UINavigationController).topViewController as! DetailViewController
                controller.detailItem = object

                controller.navigationItem.leftBarButtonItem = splitViewController?.displayModeButtonItem
                controller.navigationItem.leftItemsSupplementBackButton = true
            }
        }
    }
}

class DetailViewController: UIViewController,UINavigationControllerDelegate {

    @IBOutlet weak var detailDescription: UITextField!

    func configureView() {

        // Update the user interface for the detail item.
        if let detail = detailItem {

            if let label = detailDescription {
                label.text = detail.description
                list.append(label.text!)
            }
        }
    }
}

Answer 1

我建议使用回调闭包来更新模型并重新加载行。回调在module Core require "initial_create_helper" describe Member do describe "automerge" do before(:each) do @organization = create(:organization) @department1 = create(:organization_department,organization: @organization) @department2 = create(:organization_department,organization: @organization) @user = create(:user) @user_with_many_employments = create(:user) @department1.employments.create!(user: @user) @department1.employments.create!(organization: @organization, user: @user_with_many_employments) @department2.employments.create!(organization: @organization, user: @user_with_many_employments) @project = create_project @project.members.create!(user: @user, organization: @organization) @project.members.create!(user: @user_with_many_employments, organization: @organization) end it "::can_not_automerged" do expect(Member.can_not_automerged(@department1).to_a.map(&:user)).to match_array [@user_with_many_employments] end it "::can_automerged" do expect(Member.can_automerged(@department1).to_a.map(&:user)).to match_array [@user] end end end end中调用。闭包中的代码检查值是否不同并更新模型并在必要时重新加载行。

在DetailViewController中创建一个回调
```
viewDidDisappear
```
- 在var callback : ((String)->())?调用回调（或者可能已在viewDidDisappear中）
```
viewWillDisappear
```
在MasterViewController中添加override func viewDidDisappear(_ animated: Bool) { super.viewDidDisappear(animated) callback?(detailDescription.text!) }
中的闭包
```
prepare(for
```

Answer 2

您可以使用委托模式：

protocol DetailViewDelegate: class {
    func detailViewDidUpdate(from: String?, to: String?)
}

class DetailViewController : UIViewController {

    var detailItem: String?

    weak var delegate: DetailViewDelegate?

    @IBOutlet weak var textField: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()
        self.textField.text = detailItem
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        self.delegate?.detailViewDidUpdate(from: detailItem, to: textField.text)
    }
}

然后在 MasterViewController ：

中

extension MasterViewController: DetailViewDelegate {
    func detailViewDidUpdate(from: String?, to: String?) {
        guard let originalValue = from, let newValue = to else {
            return
        }

        if let indexPath = self.objects.index(of: originalValue) {
            self.objects[indexPath] = newValue
            // We assume here that there is only one section
            let newIndexPath = IndexPath(row: indexPath, section: 0)
            self.tableView.reloadRows(at: [newIndexPath], with: .automatic)
        }
    }
}

不要忘记在MasterController中配置DetailViewController的委托变量 prepare（对于segue：UIStoryboardSegue，sender：Any？）方法

Answer 3

当您点按后退按钮时，将会调用 viewWillAppear ，其中一个View Controller Lifecycle

例如

override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        self.tableView.reloadData()
    }

如何使用后退按钮更新tableviewcell？

3 个答案: