过滤 UItableview Swift IOS

Posted 2023-03-11

【中文标题】过滤 UItableview Swift IOS

【英文标题】：Filtering UItableview Swift IOS

【发布时间】：2018-01-21 09:20:00

【问题描述】：

我正在尝试根据从另一个 VC 传回的变量过滤 UITableView，该 VC 是处理过滤器 UI 的 Eureka 表单。

我想根据这两个变量过滤表格视图：

 var filterByPrice: Float?

 var filteredRentalTypes: Set<String>?

我的价格过滤器工作正常，但我无法过滤租赁类型。可能有一种更有效的方法来做到这一点，但这是我到目前为止的代码。使用我当前的代码，租赁类型过滤器出现“索引超出范围”崩溃。

这是我的 TableViewVC：

class RentalTableViewVC: UIViewController, UITableViewDataSource, UITableViewDelegate  

var rentalsArray = [Rental]()
var filteredArrary = [Rental]()
var myRentals = [String]()

var filterByPrice: Float?
var filteredRentalTypes: Set<String>?


static var imageCache: NSCache<NSString, UIImage> = NSCache()


@IBOutlet weak var tableView: UITableView!

var hidingBarMangar: HidingNavigationBarManager?


override func prepare(for segue: UIStoryboardSegue, sender: Any?) 
    if segue.identifier == "toDetailVC" 
        let destination = segue.destination as? DetailVC
        let value = tableView.indexPathForSelectedRow?.row

        if filteredArrary.count != 0 

            destination?.emailAdress = filteredArrary[value!].email!
            destination?.bond = filteredArrary[value!].bond!
            destination?.dateAval = filteredArrary[value!].dateAval!
            destination?.pets = filteredArrary[value!].pets!
            destination?.rent = filteredArrary[value!].price!
            destination?.rentalTitle = filteredArrary[value!].title!
            destination?.imageURL = filteredArrary[value!].imageURL!
            destination?.des = filteredArrary[value!].description!
            destination?.rentalType = filteredArrary[value!].rentalType!
            destination?.streetName = filteredArrary[value!].streetName!
            destination?.city = filteredArrary[value!].city!
            destination?.postcode = filteredArrary[value!].postcode!
         else 
            destination?.emailAdress = rentalsArray[value!].email!
            destination?.bond = rentalsArray[value!].bond!
            destination?.dateAval = rentalsArray[value!].dateAval!
            destination?.pets = rentalsArray[value!].pets!
            destination?.rent = rentalsArray[value!].price!
            destination?.rentalTitle = rentalsArray[value!].title!
            destination?.imageURL = rentalsArray[value!].imageURL!
            destination?.des = rentalsArray[value!].description!
            destination?.rentalType = rentalsArray[value!].rentalType!
            destination?.streetName = rentalsArray[value!].streetName!
            destination?.city = rentalsArray[value!].city!
            destination?.postcode = rentalsArray[value!].postcode!
        
    



func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int 
    if filteredArrary.count != 0 
        return filteredArrary.count
     else 
        return rentalsArray.count
    



func numberOfSections(in tableView: UITableView) -> Int 
    return 1


func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell 

  var rental = rentalsArray[indexPath.row]

    if self.filteredArrary.count != 0 
        rental = filteredArrary[indexPath.row]
    


    if let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as? RentalCell 




        var rentalImage = ""

        if rental.imageURL != nil 
            rentalImage = rental.imageURL!
        


        if let img = RentalTableViewVC.imageCache.object(forKey: rentalImage as NSString) 
            cell.configureCell(rental: rental, image: img)

            return cell
         else 
            cell.configureCell(rental: rental, image: nil)

            return cell
        

     else 
        return RentalCell()
    






@IBAction func backPressed(_ sender: Any) 
    dismiss(animated: true, completion: nil)


override func viewWillAppear(_ animated: Bool) 
    super.viewWillAppear(animated)
    hidingBarMangar?.viewWillAppear(animated)


override func viewDidLayoutSubviews() 
    super.viewDidLayoutSubviews()
    hidingBarMangar?.viewDidLayoutSubviews()


override func viewWillDisappear(_ animated: Bool) 
    super.viewWillDisappear(animated)
    hidingBarMangar?.viewWillDisappear(animated)

override func viewDidLoad() 
    super.viewDidLoad()



    tableView.dataSource = self
    tableView.dataSource = self

    //Firebase observer
    DataService.ds.DBrefRentals.observe(.value)  (snapshot) in

        self.rentalsArray = []
        self.filteredArrary = []

        if let snapshots = snapshot.children.allObjects as? [DataSnapshot] 
            for snap in snapshots 
                if let dicOfRentals = snap.value as? Dictionary<String,AnyObject> 

                    let key = snap.key

                    let rental = Rental(postID: key, userData: dicOfRentals)
                    self.rentalsArray.append(rental)

                    //Placing filtered items in the filtered array
                    if self.filterByPrice != nil 
                        let priceAsFloat = (rental.price! as NSString).floatValue

                        if self.filterByPrice! >= priceAsFloat 
                            self.filteredArrary.append(rental)
                        
                    

                    if self.filteredRentalTypes != nil 


                        for rentals in self.filteredRentalTypes! 
                        if rental.rentalType == rentals 
                            print("******hh\(String(describing: self.filteredRentalTypes))")
                            self.filteredArrary.append(rental)
                                

                        
                    


                
            
            self.tableView.reloadData()
        



    
    addHidingBar()




override func viewDidAppear(_ animated: Bool) 
    print("**********\(String(describing: filterByPrice)))")




func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) 
    rentalsArray[indexPath.row].incrimentViews()

    let postViewsToFB = DataService.ds.DBrefRentals.child(rentalsArray[indexPath.row].postID!)

    postViewsToFB.child("views").setValue(rentalsArray[indexPath.row].views)

     performSegue(withIdentifier: "toDetailVC" , sender: nil)






func addHidingBar() 


    let extensionView = UIView(frame: CGRect(x: 0, y: 0, width: view.frame.size.width, height: 40))
    extensionView.layer.borderColor = UIColor.lightGray.cgColor
    extensionView.layer.borderWidth = 1
    extensionView.backgroundColor = UIColor(white: 230/255, alpha: 1)
    /*let label = UILabel(frame: extensionView.frame)
    label.text = "Extension View"
    label.textAlignment = NSTextAlignment.center
    extensionView.addSubview(label) */

    let btn = UIButton(frame: CGRect(x: 20, y: 15, width: 75, height: 10))
    btn.setTitle("Filter", for: .normal)
    let btnColour = UIColor(displayP3Red: 0.0, green: 122.0/255.0, blue: 1.0, alpha: 1.0)
    btn.setTitleColor(btnColour, for: .normal)
    btn.titleLabel?.font = headerFont
    btn.addTarget(self, action: #selector(filterBtnPressed), for: .touchUpInside)

    extensionView.addSubview(btn)
    hidingBarMangar = HidingNavigationBarManager(viewController: self, scrollView: tableView)
    hidingBarMangar?.addExtensionView(extensionView)



@objc func filterBtnPressed() 
    performSegue(withIdentifier: "toFilterVC", sender: nil)

【问题讨论】：

不相关，但从数组 (filteredArrary[value!]) 中获取并强制展开 12 次（！）相同的值是不必要的昂贵。这是很坏的习惯。如果集合类型（或字符串）为空，永远不会检查.count == 0。有一个优化的属性isEmpty。而且你使用了太多的问号和感叹号。

感谢您的反馈 vadian，我将审查该代码。

【参考方案1】：

您可能会在 numberOfRows 中返回不同的数组，并且它们的大小可能不同，因此在索引任何数组之前检查计数，好像数组 count != 0 并不意味着您可以使用可能大于 0 的索引 path.row 对其进行索引，在 cellForRow 中更改这一行

   if self.filteredArrary.count != 0 
    rental = filteredArrary[indexPath.row]

到

  if  indexPath.row < self.filteredArrary.count  
    rental = filteredArrary[indexPath.row]

【讨论】：

当我选择“整个房屋”过滤器时，我仍然有索引超出范围，并且选择其他筛选器不会更改TableView时。有什么想法吗？