快速购物应用程序的加号和减号按钮

Question

我有问题。我找不到使这些按钮正常工作的方法，我需要一些帮助。

我正在尝试为一家餐厅创建应用程序，但我不知道如何使加号和减号按钮正常工作。我从 Firebase 中提取数据（产品的名称和价格）。我有金额标签。点击加号，然后点击减号。

这是我的viewController中的代码：

import UIKit
import Firebase
import FirebaseDatabase

class foodListViewController: UIViewController, UITableViewDelegate, UITableViewDataSource{

@IBOutlet weak var plus: UIButton!
@IBOutlet weak var foodTableView: UITableView!
var ref:DatabaseReference?
var databaseHandle: DatabaseHandle?
var foodData = [food]()
var stats = [Buy]()

override func viewDidLoad() {
    super.viewDidLoad()

    foodTableView.delegate = self
    foodTableView.dataSource = self
    foodTableView.backgroundView = UIImageView(image: UIImage(named: "bg-general.png"))
    foodTableView.allowsSelection = false
    foodTableView.separatorStyle = .none

    //Set the firebase reference
    ref = Database.database().reference()

    //Retrieve the data and listen for changes
ref?.child("inventory").child("food").observe(.childAdded, with: { (snapshot) in
   /*    if let dict = snapshot.value as? [String: AnyObject] {
        let foods = food()
            foods.setValuesForKeys(dict)
            print(foods.FirstName!)
            //self.foodTableView.reloadData()
    }*/
    print(snapshot)
    if let dictionary = snapshot.value as? [String: AnyObject] {
        let foods = food()
       // foods.setValuesForKeys(dictionary)
        foods.title = dictionary["title"] as? String
        foods.amount = dictionary["amount"] as? String
        foods.price = dictionary["price"] as? Double
        foods.category = dictionary["category"] as? String
        foods.id = dictionary["id"] as? String

        self.foodData.append(foods)


       DispatchQueue.main.async {
            print("BlaBlaBla")
            self.foodTableView.reloadData()
       }
      //  print(foods.title!,foods.amount!,foods.price!,foods.category!,foods.id!)

    }

    })

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

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

func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
    return 140;
}

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "FoodCell", for: indexPath)

    let food = foodData[indexPath.row]
    // Food and price
    let titleLabel = cell.viewWithTag(1) as! UILabel
    let priceLabel = cell.viewWithTag(2) as! UILabel
    let cantitateLabel = cell.viewWithTag(3) as! UILabel

    //Labels text size
   // titleLabel.font = UIFont(name: "Times New Roman-Bold", size: 30)
  //  priceLabel.font = UIFont(name: "Times New Roman-Bold", size: 17.0)
  //  cantitateLabel.font = UIFont(name: "Times New Roman-Bold", size: 17.0)



    titleLabel.text = food.title
    let numberFormatter = NumberFormatter()
    numberFormatter.numberStyle = .decimal
    priceLabel.text = numberFormatter.string(from: food.price! as NSNumber)! + " $"

    // Design for table
    cell.backgroundColor = UIColor.clear
    cell.contentView.backgroundColor = UIColor.clear
    let whiteRoundedView : UIView = UIView(frame: CGRect(x: 0, y: 10, width: self.view.frame.size.width, height: 70))
    whiteRoundedView.backgroundColor = UIColor.greenColor
    whiteRoundedView.layer.masksToBounds = false
    whiteRoundedView.layer.cornerRadius = 3.0
    whiteRoundedView.layer.shadowOffset = CGSize(width: -1, height: 1)
    whiteRoundedView.layer.shadowOpacity = 0.5
    cell.contentView.addSubview(whiteRoundedView)
    cell.contentView.sendSubview(toBack: whiteRoundedView)

    //Plus - Minus
    let pluss = cell.viewWithTag(4) as! UIButton
    let minuss = cell.viewWithTag(5) as! UIButton

    //pluss.addTarget(self, action: #selector(plusss(cantitate: amount)), for: .touchUpInside)
  //  minuss.addTarget(self, action: #selector(minusss(cantitate: amount)), for:. touchUpInside)



    return cell

}

}

此外，按加号会将我的产品添加到另一个我的订单列表中的viewcontroller。按下减号将减少金额，当金额为0时，它将从订单列表中删除我的产品。

谢谢。

Answer 1

您需要一个用于此类按钮的IBAction ...我建议您使用带有按钮和标签的原型tableViewCell并在相应的视图控制器中处理操作。

Answer 2

这就是我管理两个不同按钮以用作步进器的方式

我的数组，用于存储需要更新的值

var meanValuesArray : [String] = ["","","0","0","0","1","1","",""]

枚举函数，用于证明要执行的任务的正确性

//MARK: math Function Enum
/**
 This Enum is used to Detect do Add Math Operation or Subtract action is to be Performed
 */
enum mathFunction {
    /// When Addition is to done
    case Add
    /// When Subtraction is to be Done
    case Subtract
}

单元格用于行方法

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = self.addPropertyTableView.dequeueReusableCell(withIdentifier: "APStepperSwitch", for: indexPath) as! addPropertyWithStepperSwitch
        cell.staticImageView.image = self.leftImagesArray[indexPath.row]
        cell.propertyDetailLabel.text = self.leftValueArray[indexPath.row]
        cell.propertyStepperLabel.text = self.meanValuesArray[indexPath.row]

        /// Adding Button Handlers
        cell.propertyPlusButton.addTarget(self, action: #selector(AddingPropertyVC.plusButtonHandler(sender:)), for: UIControlEvents.touchUpInside)
        cell.propertyMinusButton.addTarget(self, action: #selector(AddingPropertyVC.minusButtonHandler(sender:)), for: UIControlEvents.touchUpInside)
        return cell
    }

按钮操作

@objc func minusButtonHandler(sender: UIButton) {
        /// Getting The Button Position Which is clicked
        let buttonPosition : CGPoint = sender.convert(CGPoint.zero, to: self.addPropertyTableView)

        /// Getting Index Path From Button Location
        let indexPath : IndexPath = self.addPropertyTableView.indexPathForRow(at: buttonPosition)!

        /// Extracting and Updating my current Order Value Either + or -
        self.meanValuesArray[indexPath.row] = AFWrapperClass.compareStringValue(currentValue: self.meanValuesArray[indexPath.row], limit: 20, toDo: .Subtract)

        /// Reloading Table
        self.addPropertyTableView.reloadData()
    }

    @objc func plusButtonHandler(sender: UIButton) {
        /// Getting The Button Position Which is clicked
        let buttonPosition : CGPoint = sender.convert(CGPoint.zero, to: self.addPropertyTableView)

        /// Getting Index Path From Button Location
        let indexPath : IndexPath = self.addPropertyTableView.indexPathForRow(at: buttonPosition)!

        /// Extracting and Updating my current Order Value Either + or -
        self.meanValuesArray[indexPath.row] = AFWrapperClass.compareStringValue(currentValue: self.meanValuesArray[indexPath.row], limit: 20, toDo: .Add)

        /// Reloading Table
        self.addPropertyTableView.reloadData()
    }

主要步进功能

class AFWrapperClass : NSObject {
        //MARK: Fucntion used to comapre and update value
        /**
         This function is used to update stepper values
         - parameter currentValue : Current Value in Array
         - parameter limit : Maximum Value that can be used as stepper+1
         - parameter toDo : tells need to perform Add or subtract
         */
        class func compareStringValue(currentValue:String, limit:Int, toDo : mathFunction) -> String {
            var current : Int = Int(currentValue)!
            if (current <= limit) && (current >= 0) {
                if toDo == .Add {
                    if current == limit {
                        return String(current)
                    }
                    else{
                        current += 1
                        return String(current)
                    }
                }
                else {
                    if current == 0 {
                        return String(current)
                    }
                    else {
                        current -= 1
                        return String(current)
                    }
                }
            }
            else {
                return String(current)
            }
        }
    }