Question

我有一个简单的应用程序，其中包含CollectionView和其中的项目。长按cell弹出式UIView会显示TextField，并可选择将其保存在与array对应的cell中。

以下是代码（在buttons方法中已正确添加gestures和viewDidLoad()）：

class CollectionViewController: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate  {
var longPressedPoint: CGPoint?

public var rowOfLongPressedItem: Int? = nil

func handleLongPress(longPressRecognizer: UILongPressGestureRecognizer)  -> Int      {
    print("LONG PRESS Gesture Recognized")
    notePopup.hidden = false
    longPressedPoint =  longPressRecognizer.locationInView(longPressRecognizer.view)
    var indexPathOfLongPressedCell = self.itemCollectionView.indexPathForItemAtPoint(longPressedPoint!)
    rowOfLongPressedItem = (indexPathOfLongPressedCell?.row)
    print("rowOfLongPressedItem -> .\(rowOfLongPressedItem)")
    return rowOfLongPressedItem!
}

func saveNoteButtonTapped(rowOfLongPressedItem: Int) {
    print("rowOfLongPressedItem when Save button is tapped -> .\(rowOfLongPressedItem)")       

    //Can’t go further down as rowOfLongPressedItem is NOT available from “handleLongPress” function…

    var selectedItem = ItemsList[rowOfLongPressedItem]
    selectedItem.counts += 1
    var latest = selectedItem.counts - 1
    selectedItem.timestamp.append(NSDate())
    selectedItem.note.append(noteTextField.text)
    ItemsList[rowOfLongPressedItem] = selectedItem
    print(".\(selectedItem.title) has been tapped .\(selectedItem.counts)")
    print("The latest tap on .\(selectedItem.title) is at .\(selectedItem.timestamp[latest])")
    print("The note .\(noteTextField.text) has been added")
    notePopup.hidden = true
}
}

试图通过以下两种方式解决问题：

在View Controller中定义一个变量，希望该函数返回该值并将其保存在全局变量中。但是，后来从Apple那里发现了 “函数不能具有比其参数类型和返回类型更高的访问级别，因为该函数可用于其组成类型不可用于周围代码的情况。” https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/AccessControl.html
我尝试将Button的Selector功能代码放在Long Press Gesture Function中，以便它的返回值很容易获得。但是，我无法调用Selector函数，因为它在另一个函数中。
此外，我尝试返回Long Press Gesture Function的值并在“保存”按钮的IBAction中使用它。但是，为此，我需要再次调用handleLongPress，然后将longPressedPoint检测为内部“保存”按钮。因此，indexPathOfLongPressedCell为nil，应用程序崩溃。

有人可以帮助我......

Answer 1

假设您想要获取所选单元格的行并将其分配给全局变量Date，则不需要让const d1 = new Date('1970-01-18T00:00:00+00:00'); // Numeric value as the number of milliseconds since UNIX epoch. const time = d1.getTime(); db.executeAsync(insertQuery, [ id, d1 ], { prepare: true } ); // ... db.executeAsync(selectQuery, [ id ], { prepare: true }) .then((result) => { console.log('Are equal?', time, result.first()['date_created'].getTime()) })返回Int。

注意：这是一个Swift 3代码（概念相同）：

rowOfLongPressedItem

此外，您无需让handleLongPress获取public var rowOfLongPressedItem: Int? = nil override func viewDidLoad() { //... let longPressRecognizer = UILongPressGestureRecognizer(target: self, action: #selector(ViewController.assignRowOfLongPressedItem)) itemCollectionView.addGestureRecognizer(longPressRecognizer) //... } func assignRowOfLongPressedItem(longPressRecognizer: UILongPressGestureRecognizer) { let longPressedPoint = longPressRecognizer.location(in: longPressRecognizer.view) var indexPathOfLongPressedCell = self.itemCollectionView.indexPathForItem(at: longPressedPoint) rowOfLongPressedItem = (indexPathOfLongPressedCell?.row) // if you long press the first row -for example-, the output should be: "rowOfLongPressedItem -> .Optional(0)" print("rowOfLongPressedItem -> .\(rowOfLongPressedItem)") }参数。请注意，saveNoteButtonTapped是可选的，您应该确保它仍然是零（您可以使用Early Exit方法）：

rowOfLongPressedItem

Answer 2

两个函数都可以使用

rowOfLongPressedItem。您无需将其设为saveNoteButtonTapped。

的参数

var rowOfLongPressedItem: Int? = nil

func handleLongPress(longPressRecognizer: UILongPressGestureRecognizer)  -> Int      {
    print("LONG PRESS Gesture Recognized")
    notePopup.hidden = false
    longPressedPoint =  longPressRecognizer.locationInView(longPressRecognizer.view)
    var indexPathOfLongPressedCell = self.itemCollectionView.indexPathForItemAtPoint(longPressedPoint!)
    rowOfLongPressedItem = (indexPathOfLongPressedCell?.row)
    print("rowOfLongPressedItem -> .\(rowOfLongPressedItem)")
    return rowOfLongPressedItem!
}

func saveNoteButtonTapped() {

    guard let row = rowOfLongPressedItem else {
        return // rowOfLongPressedItem was nil
    }

    print("rowOfLongPressedItem when Save button is tapped -> .\(row)")
    var selectedItem = ItemsList[row]

    selectedItem.counts += 1
    var latest = selectedItem.counts - 1
    selectedItem.timestamp.append(NSDate())
    selectedItem.note.append(noteTextField.text)
    ItemsList[row] = selectedItem
    print(".\(selectedItem.title) has been tapped .\(selectedItem.counts)")
    print("The latest tap on .\(selectedItem.title) is at .\(selectedItem.timestamp[latest])")
    print("The note .\(noteTextField.text) has been added")
    notePopup.hidden = true
}

将变量从Gesture Recognizer函数传递给IBAction

2 个答案: