swift - didselectrow 更新下面的多个单元格重新加载 TableView + 计数器

Question

这是一个由两部分组成的问题，第一个问题是在我花了整整一周试图弄清楚这一点之后，我仍然一片空白。我终于让各个单元格显示与文本字段中的选择相关的适当数字，但仍然没有弄清楚为什么重新加载到表格 View 中的单元格也显示更新的文本字段。基本上，我只想仅在选定的行中更新 cardCounter 的文本字段，然后如果用户滚动回原来的位置(如果他们决定删除它)，则会向他们显示该对象中有多少可用的计数器。

第二个问题是我正在尝试为总限制为 30 的 cardCount 创建一个计数器，并且对于所选的每个 cardCount 对象，这 30 个选择中的 1 个已缩小到 29、28、27 等。只是想完成我的第一个项目的一些小代码。

import UIKit
import CoreData

class CardSelectionViewController: UIViewController, UITableViewDelegate, UIAlertViewDelegate, UISearchBarDelegate, NSFetchedResultsControllerDelegate {

var passedDeckObject: Deck?
let managedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

var deckCardCount = 30

@IBOutlet weak var cardsListed: UITableView!

@IBOutlet weak var cardSearch: UISearchBar!


@IBAction func backButton(sender: AnyObject) {
}

@IBAction func saveCardSelection(sender: AnyObject) {

    if deckCardCount != 30 {

    let selectmorecards = UIAlertController(title: "Select More Cards", message: "Please Select More Cards To Complete Deck", preferredStyle: .Alert)
    let okCardAction: UIAlertAction = UIAlertAction(title: "OK", style: .Cancel, handler: nil)
        selectmorecards.addAction(okCardAction)
        self.presentViewController(selectmorecards, animated: true, completion: nil)

    } else {

    if deckCardCount == 30 {
    let alertController = UIAlertController(title: "All Cards Correct?", message: "Are all the cards in the deck what you wanted?", preferredStyle: .Alert)
    let cancelAction: UIAlertAction = UIAlertAction(title: "Cancel", style: .Cancel, handler: nil)
    let okAction: UIAlertAction = UIAlertAction(title: "OK", style: .Default) { (action) -> Void in
        self.managedObjectContext?.save(nil)

        self.presentViewController(alertController, animated: true, completion: nil)

        }
        }
    }
}

var costfrc: NSFetchedResultsController!
var frc: NSFetchedResultsController = NSFetchedResultsController()
func getFetchedResultsController() -> NSFetchedResultsController {
    frc = NSFetchedResultsController(fetchRequest: listFetchRequest(), managedObjectContext: managedObjectContext!, sectionNameKeyPath: nil, cacheName: nil)

    return frc

}
func listFetchRequest() -> NSFetchRequest {

    let requiredClassName = passedDeckObject!.classSelected.classname
    var requiredCardClasses = [Int]()
    let fetchRequest = NSFetchRequest(entityName: "Cards")
    let sortDescriptor = NSSortDescriptor(key: "name", ascending: true)
    switch(requiredClassName) {
        case "Warrior":
        requiredCardClasses = [1,10]
        case "Shaman":
        requiredCardClasses = [2,10]
        case "Rogue":
        requiredCardClasses = [3,10]
        case "Paladin":
        requiredCardClasses = [4,10]
        case "Hunter":
        requiredCardClasses = [5,10]
        case "Druid":
        requiredCardClasses = [6,10]
        case "Warlock":
        requiredCardClasses = [7,10]
        case "Mage":
        requiredCardClasses = [8,10]
        case "Priest":
        requiredCardClasses = [9,10]
        default:
        requiredCardClasses = [10]
    }
    fetchRequest.sortDescriptors = [sortDescriptor]
    fetchRequest.predicate = NSPredicate(format:"cardClass IN %@", requiredCardClasses)

    return fetchRequest
}

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    let numberofRowsInSection = frc.sections?[section].numberOfObjects
    return numberofRowsInSection!
}


//Mark cell displayed with colored text//
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

    var cell: firstCardDetails = cardsListed.dequeueReusableCellWithIdentifier("cell", forIndexPath: indexPath) as! firstCardDetails
    let listed = frc.objectAtIndexPath(indexPath) as! Cards
    var cardCount = 0
    var myDeckCards: DeckCards?
    for eachDeckCard in listed.cardselections {
        let myDeckCard = eachDeckCard as! DeckCards
        if myDeckCard.cardsstored == passedDeckObject {
            myDeckCards = eachDeckCard as? DeckCards
            cardCount = myDeckCards!.numberSelected.integerValue
        }
    }




    cell.cardName?.text = listed.name as String
    if listed.cardType.isEqualToValue(1) {
        cell.cardAttack?.text = "*"
    } else {
        if listed.cardType.isEqualToValue(2) {
            cell.cardAttack?.text = "*"
        } else {
    cell.cardAttack?.text = listed.attack.stringValue
    }
    }
    if listed.cardType.isEqualToNumber(1) {
        cell.cardHealth?.text = "*"
    } else {
        if listed.cardType.isEqualToValue(2) {
            cell.cardHealth?.text = "*"
        } else {
    cell.cardHealth?.text = listed.health.stringValue
    }
    }
    cell.cardCost?.text = listed.cost.stringValue

        if listed.cardType.isEqualToNumber(0) {
            cell.cardType?.text = "Minion"
        } else {
            if listed.cardType.isEqualToNumber(1) {
                cell.cardType?.text = "Spell"
            } else {
                if listed.cardType.isEqualToNumber(2) {
                cell.cardType?.text = "Weapon"
            }
            }
    }
    if listed.rarity.isEqualToNumber(1) {
        cell.rarityType?.text = "Legendary"
        cell.rarityType?.textColor = UIColor.orangeColor()
    } else {
        if listed.rarity.isEqualToNumber(2) {
            cell.rarityType?.text = "Epic"
            cell.rarityType?.textColor = UIColor.purpleColor()
        } else {
            if listed.rarity.isEqualToNumber(3) {
                cell.rarityType?.text = "Rare"
                cell.rarityType?.textColor = UIColor.blueColor()
            } else {
                if listed.rarity.isEqualToNumber(4) {
                    cell.rarityType?.text = "Common"
                    cell.rarityType?.textColor = UIColor.grayColor()
                } else {
                    if listed.rarity.isEqualToNumber(5) {
                        cell.rarityType?.text = "Starter"
                        cell.rarityType?.textColor = UIColor.blackColor()
                    }
                }
            }
        }
    }
    if listed.cardClass.isEqualToNumber(1) {
        cell.cardName?.textColor = UIColor(red: 0xbe/255, green: 0x23/255, blue: 0x0f/255, alpha: 1.0)
    } else {
        if listed.cardClass.isEqualToNumber(2) {
            cell.cardName?.textColor = UIColor.blueColor()
        } else {
            if listed.cardClass.isEqualToNumber(3) {
                cell.cardName?.textColor = UIColor(red: 0xE2/255, green: 0xA8/255, blue: 0x79/255, alpha: 1.0)
            } else {
                if listed.cardClass.isEqualToNumber(4) {
                    cell.cardName?.textColor = UIColor(red: 0xFF/255, green: 0xAA/255, blue: 0x00/255, alpha: 1.0)
                } else {
                    if listed.cardClass.isEqualToNumber(5) {
                        cell.cardName?.textColor = UIColor(red: 0x22/255, green: 0x63/255, blue: 0x29/255, alpha: 1.0)
                    } else {
                        if listed.cardClass.isEqualToNumber(6) {
                            cell.cardName?.textColor = UIColor.brownColor()
                        } else {
                            if listed.cardClass.isEqualToNumber(7) {
                                cell.cardName?.textColor = UIColor(red: 0xBB/255, green: 0x76/255, blue: 0xE4/255, alpha: 1.0)
                            } else {
                                if listed.cardClass.isEqualToNumber(8) {
                                    cell.cardName?.textColor = UIColor(red: 0x9E/255, green: 0xB5/255, blue: 0xFF/255, alpha: 1.0)
                                } else {
                                    if listed.cardClass.isEqualToNumber(9) {
                                        cell.cardName?.textColor = UIColor.grayColor()
                                    } else {
                                        if listed.cardClass.isEqualToNumber(10) {
                                            cell.cardName?.textColor = UIColor.blackColor()
                                        }
                                        }
                                }
                            }

                            }
                        }
                    }
                }
        }
    }
    return cell
}
//reload content//
func controllerDidChangeContent(controller: NSFetchedResultsController) {
    cardsListed.reloadData()
}


//selected row functions//
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    var cardCount = 0
    var myDeckCards: DeckCards?
    let listed = frc.objectAtIndexPath(indexPath) as! Cards


    var cell = cardsListed.cellForRowAtIndexPath(indexPath) as! firstCardDetails

    cell.indexOfAccessibilityElement(listed)

    // check: is there already a DeckCards object for this Card and this Deck?
    let deckCardsSet = listed.cardselections
    println("The set of DeckCards for that Card is \(deckCardsSet.count)")
    for eachDeckCard in listed.cardselections {
        let myDeckCard = eachDeckCard as! DeckCards
        if myDeckCard.cardsstored == passedDeckObject {
            // There is already a DeckCard object for this Card and currentDeck
            myDeckCards = eachDeckCard as? DeckCards
        }
    }
    if myDeckCards == nil {
        // There is no DeckCard object for this Card and currentDeck
        // So create one...
        myDeckCards = NSEntityDescription.insertNewObjectForEntityForName("DeckCards", inManagedObjectContext: managedObjectContext!) as? DeckCards
        myDeckCards!.cardsselected = listed
        myDeckCards!.cardsstored = passedDeckObject!
    }
    // your code to determine numberSelected here; I'll assume 2!
    cardCount = myDeckCards!.numberSelected.integerValue
    deckCardCount = myDeckCards!.deckcardCount.integerValue


    cardCount = cardCount == 2 ? 0 : cardCount + 1
    myDeckCards!.numberSelected = cardCount
    deckCardCount = deckCardCount - cardCount
    cell.cardCounter.text = "  " + cardCount.description
        if deckCardCount == 30 {
            if cell.selected {
                deckCardCount = deckCardCount + 1
            }
        myDeckCards!.numberSelected = deckCardCount
        myDeckCards!.numberSelected = cardCount
        }
    println(deckCardCount)
    println(cardCount)

}

//searchBar contoller//
func searchBar(searchBar: UISearchBar, textDidChange searchText: String) {

    searchBar.setShowsCancelButton(true, animated: true)
    let requiredClassName = passedDeckObject!.classSelected.classname
    var requiredCardClasses = [Int]()
    switch(requiredClassName) {
    case "Warrior":
        requiredCardClasses = [1,10]
    case "Shaman":
        requiredCardClasses = [2,10]
    case "Rogue":
        requiredCardClasses = [3,10]
    case "Paladin":
        requiredCardClasses = [4,10]
    case "Hunter":
        requiredCardClasses = [5,10]
    case "Druid":
        requiredCardClasses = [6,10]
    case "Warlock":
        requiredCardClasses = [7,10]
    case "Mage":
        requiredCardClasses = [8,10]
    case "Priest":
        requiredCardClasses = [9,10]
    default:
        requiredCardClasses = [10]
    }
    if !searchText.isEmpty {
        // Clear out the fetchedResultController
        frc = getFetchedResultsController()
        // Setup the fetch request
        let fetchRequest = NSFetchRequest(entityName: "Cards")
        fetchRequest.fetchLimit = 565
        fetchRequest.predicate = NSCompoundPredicate(type: .AndPredicateType, subpredicates: [NSPredicate(format: "name contains[cd] %@", searchText), NSPredicate(format: "cardClass IN %@", requiredCardClasses)])
        let sortDescriptor = NSSortDescriptor(key: "name", ascending: true)
        fetchRequest.sortDescriptors = [sortDescriptor]
        println(fetchRequest.predicate)
        //end//
        //cost fetch request begins here//
        let costfetchRequest = NSFetchRequest(entityName: "cardCost")
        costfetchRequest.fetchLimit = 565
        costfetchRequest.predicate = NSPredicate(format: "cardCost = %i", searchText)
        let costSortDescriptor = NSSortDescriptor(key: "cardCost", ascending: true)
        costfetchRequest.sortDescriptors = [sortDescriptor]
        //end//

        // Pass the fetchRequest and the context as parameters to the fetchedResultController
        frc = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext:managedObjectContext!,
            sectionNameKeyPath: nil, cacheName: nil)
        // Make the fetchedResultController a delegate of the MoviesViewController class
        frc.delegate = self
        // Execute the fetch request or display an error message in the Debugger console
        var error: NSError? = nil
        if (!frc.performFetch(&error)) {
            println("Error: \(error?.localizedDescription)")
        }
        // Refresh the table view to show search results
        cardsListed.reloadData()
    }
}
//search Cancel
func searchBarCancelButtonClicked(searchBar: UISearchBar) {
    searchBar.text = nil
    searchBar.showsCancelButton = false // Hide the cancel
    searchBar.resignFirstResponder() // Hide the keyboard

    // Refresh the table view to show fetchedResultController results
    cardsListed.reloadData()
}
override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {

    self.view.endEditing(true)
}
func textFieldShouldReturn(textField: UITextField) -> Bool {

    textField.resignFirstResponder()
    return true
}

override func viewDidLoad() {
    super.viewDidLoad()

    println(passedDeckObject?.deckname)
    var nib = UINib(nibName: "firstCardDetails", bundle: nil)
    cardsListed.registerNib(nib, forCellReuseIdentifier: "cell")
    frc = getFetchedResultsController()
    frc.delegate = self
    frc.performFetch(nil)


}

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

Answer 1

对于问题 #1...

当您使用可重用单元格时，在 cellForRowAtIndexPath(或 prepareForReuse)之外进行单元格更改通常不是一个好主意。也有异常(exception)，但大多数时候，这是安全的选择。最好的策略是仅在其他方法中进行数据更改，然后重新加载受影响的单元格(或全部)。

由于单元格已缓存，因此每当使用单元格时，您对单元格所做的更改都会显示在屏幕上，除非您在返回单元格时明确覆盖更改。

您应该计算所需的内容并将其存储在 didSelectRowAtIndexPath 方法中的某个位置，然后在 cellForRowAtIndexPath 中更新它的显示。