Swift 3 - iOS 10 启用 UITableView "swipe-to-delete"

Question

有很多关于如何为UITableView启用滑动删除的问题，他们都说同样的事情：

覆盖 tableView(_:commit editingStyle:forRowAt indexPath:).

我已经这样做了，但我仍然没有滑动删除功能。我尝试过的事情：

在代码和 IB 中将 tableView.allowsMultipleSelectionDuringEditing 设置为 true 和 false。
覆盖 tableView(_:canEditRowAt indexPath:) 并返回 true。
覆盖 tableView(_:editingStyleForRowAt indexPath:) 并返回 .delete。
以及以上所有组合。

我使用 FirebaseUI 和自定义 UITableViewCell 来填充 table。这是我的 table 视图控制器：

import UIKit
import FirebaseDatabaseUI

class ScheduleViewController: UITableViewController {

    private let TAG = String(describing: ScheduleViewController.self)

    private var dataSource: FUITableViewDataSource!

    override func viewDidLoad() {
        super.viewDidLoad()

        dataSource = self.tableView.bind(to: DataManager.instance.habitsQuery(),
                                         populateCell: populateCell())

        self.tableView.dataSource = dataSource

        // Automatically resize table cells to fit its content.
        self.tableView.estimatedRowHeight = ScheduleTableViewCell.HEIGHT
        self.tableView.rowHeight = UITableViewAutomaticDimension

        // I have also
        self.tableView.allowsMultipleSelectionDuringEditing = false
    }

    func populateCell() -> (UITableView, IndexPath, FIRDataSnapshot) -> UITableViewCell {
        return { tableView, indexPath, snapshot in
            let cell =
                tableView.dequeueReusableCell(withIdentifier: ScheduleTableViewCell.IDENTIFIER,
                                              for: indexPath) as! ScheduleTableViewCell

            if let dict = snapshot.value as? Dictionary<String, Any?> {
                cell.set(habit: Habit(withKey: snapshot.key, from: dict))
            } else {
                Log.e(self.TAG, "Invalid data returned from Firebase.")
            }

            return cell
        }
    }

    // MARK: TableView Delegate

    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }

    override func tableView(_ tableView: UITableView,
                            editingStyleForRowAt indexPath: IndexPath) -> UITableViewCellEditingStyle
    {
        return .delete
    }

    override func tableView(_ tableView: UITableView,
                            commit editingStyle: UITableViewCellEditingStyle,
                            forRowAt indexPath: IndexPath)
    {

    }

    // MARK: - Navigation

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

}

Answer 1

在故事板上，select 视图控制器（视图控制器顶部的黄色部分）。虽然视图控制器是 selected:

选择编辑器 > 嵌入 > 导航控制器。

将此添加到您的 viewDidLoad：

navigationItem.leftBarButtonItem = editButtonItem

因此您的 viewDidLoad 应该如下所示：

override func viewDidLoad() {
    super.viewDidLoad()

    // Use the edit button item provided by the table view controller.
    navigationItem.leftBarButtonItem = editButtonItem

    // Load the data.
}

读这个：https://developer.apple.com/library/content/referencelibrary/GettingStarted/DevelopiOSAppsSwift/ImplementEditAndDeleteBehavior.html#//apple_ref/doc/uid/TP40015214-CH9-SW1

Answer 2

最近的 FirebaseUI 更新打破了原来的答案。

更新的答案：

只需继承 FUITableViewDataSource 即可实现自定义 UITableViewDataSource 功能，然后将子类绑定到您的 UITableView.

FUITableViewDataSource 子类：

import UIKit
import FirebaseDatabaseUI

class EditableTableDataSource: FUITableViewDataSource {

    /// Called to populate each cell in the UITableView.
    typealias PopulateCellBlock = (UITableView, IndexPath, FIRDataSnapshot) -> UITableViewCell

    /// Called to commit an edit to the UITableView.
    typealias CommitEditBlock = (UITableView, UITableViewCellEditingStyle, IndexPath) -> Void

    private let commitEditBlock: CommitEditBlock?

    /// A wrapper around FUITableViewDataSource.init(query:view tableView:populateCell:), with the
    /// addition of a CommitEditBlock.
    public init(query: FIRDatabaseQuery,
                populateCell: @escaping PopulateCellBlock,
                commitEdit: @escaping CommitEditBlock)
    {
        commitEditBlock = commitEdit
        super.init(collection: FUIArray.init(query: query), populateCell: populateCell)
    }

    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }

    override func tableView(_ tableView: UITableView,
                            commit editingStyle: UITableViewCellEditingStyle,
                            forRowAt indexPath: IndexPath)
    {
        if (commitEditBlock != nil) {
            commitEditBlock!(tableView, editingStyle, indexPath)
        }
    }

}

extension UITableView {

    /// Creates a data source, binds it to the table view, and returns it. Note that this is the
    /// `EditableTableViewDataSource` equivalent of the 
    /// `FUITableViewDataSource.bind(to:populateCell:)` method.
    ///
    /// - parameters:
    ///   - to:             The Firebase query to bind to.
    ///   - populateCell:   A closure that's called to populate each cell.
    ///   - commitEdit:     A closure that's called when the user commits some kind of edit. Maps to
    ///                     `tableView(:commit:forRowAt:)`.
    func bind(to query: FIRDatabaseQuery,
              populateCell: @escaping EditableTableDataSource.PopulateCellBlock,
              commitEdit: @escaping EditableTableDataSource.CommitEditBlock)
        -> EditableTableDataSource
    {
        let dataSource = EditableTableDataSource(query: query,
                                                 populateCell: populateCell,
                                                 commitEdit: commitEdit)
        dataSource.bind(to: self)
        return dataSource
    }

}

和用法：

import UIKit
import FirebaseDatabaseUI

class ScheduleViewController: UITableViewController {

    private let TAG = String(describing: ScheduleViewController.self)

    private var dataSource: FUITableViewDataSource!
    private var dataManager: DataManager!

    override func viewDidLoad() {
        super.viewDidLoad()

        dataManager = AppManager.defaultInstance.dataManager()

        dataSource = tableView.bind(
            to: dataManager.scheduledHabitsQuery(),
            populateCell: populateCellBlock(),
            commitEdit: commitEditBlock())
    }


    // MARK: TableView Data Source

    func populateCellBlock() -> EditableTableDataSource.PopulateCellBlock {
        return { tableView, indexPath, snapshot in
            let cell = ScheduledHabitTableViewCell.from(tableView: tableView, at: indexPath)
            cell.set(habit: ScheduledHabit(fromSnapshot: snapshot))
            return cell
        }
    }

    func commitEditBlock() -> EditableTableDataSource.CommitEditBlock {
        return { tableView, editingStyle, indexPath in
            if (editingStyle != .delete) {
                return
            }

            // Delete the data from Firebase.
            let snapshot = self.dataSource.snapshot(at: indexPath.row)
            self.dataManager.moveToTrash(ScheduledHabit(fromSnapshot: snapshot))

            // Deleting the table view row is done automatically by the FirebaseUI data source.
        }
    }


    // MARK: - Navigation

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

}

原始答案：

解决方案是继承 FUITableViewDataSource 并重写您想要的 UITableViewDataSource 方法。之后一切正常。

import UIKit
import FirebaseDatabaseUI

class FUIEditableTableViewDataSource: FUITableViewDataSource {

    /// Called to populate each cell in the UITableView.
    typealias PopulateCellBlock = (UITableView, IndexPath, FIRDataSnapshot) -> UITableViewCell

    /// Called to commit an edit to the UITableView.
    typealias CommitEditBlock = (UITableView, UITableViewCellEditingStyle, IndexPath) -> Void

    private let commitEditBlock: CommitEditBlock?

    /// A wrapper around FUITableViewDataSource.init(query:view tableView:populateCell:), with the
    /// addition of a CommitEditBlock.
    public init(query: FIRDatabaseQuery,
                tableView: UITableView,
                populateCell: @escaping PopulateCellBlock,
                commitEdit: @escaping CommitEditBlock)
    {
        commitEditBlock = commitEdit
        super.init(query: query, view: tableView, populateCell: populateCell)
    }

    override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }

    override func tableView(_ tableView: UITableView,
                            commit editingStyle: UITableViewCellEditingStyle,
                            forRowAt indexPath: IndexPath)
    {
        if (commitEditBlock != nil) {
            commitEditBlock!(tableView, editingStyle, indexPath)
        }
    }

}

Swift 3 - iOS 10 启用 UITableView "swipe-to-delete"

Swift 3 - iOS 10 UITableView enabling "swipe-to-delete"

ios

swift

uitableview

firebase

firebaseui