ios - 将 TableView 的所有数据转换为 CollectionView 快速解析

Question

为了限制对我的数据库的查询次数以及数据和电池的消耗，我想将我的 TableView 的所有数据转移到我的 CollectionView。

import UIKit
import ParseUI
import Parse

class ListControllerView: PFQueryTableViewController {

   // Initialise the PFQueryTable tableview

  override init(style: UITableViewStyle, className: String!) 
   {
      super.init(style: style, className: className)
   }

  required init(coder aDecoder: NSCoder) 
    {
       super.init(coder: aDecoder)!

       // Configure the PFQueryTableView
       self.parseClassName = "Shopz"
       self.textKey = "shopName"
       self.pullToRefreshEnabled = true
       self.paginationEnabled = false
    }

   // Define the query that will provide the data for the table view
   override func queryForTable() -> PFQuery {
      var query = PFQuery(className: "Shopz")
      // query.orderByAscending("updatedAt")
      return query
   }

   //override func tableView(tableView: UITableView,       cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
   override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath, object: PFObject?) -> PFTableViewCell {

    var cell = tableView.dequeueReusableCellWithIdentifier("Cell") as! ListControllerViewCell!
    if cell == nil {
        cell = ListControllerViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell")
    }

    // Display flag image

   if let finalImage = object?["imagePromo"] as? PFFile
    {
        finalImage.getDataInBackgroundWithBlock
            {(imageData: NSData?, error: NSError?) -> Void in
            if error == nil
            {
                if let imageData = imageData
                {
                    cell.ImagePromo!.image = UIImage(data:imageData)
                }
            }
           }
    }

    // Extract values from the PFObject to display in the table cell
    if let shopnamelabel = object?["shopName"] as? String
    {
        cell.ShopName!.text = shopnamelabel
        print(shopnamelabel)
    }

    if let shopaddresslabel = object?["shopAddress"] as? String
    {
        cell.ShopAddress!.text = shopaddresslabel
        print(shopaddresslabel)
    }



        return cell;
 }


// In a storyboard-based application, you will often want to do a little preparation before navigation

   override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {

    // Get the new view controller using [segue destinationViewController].
    var detailScene = segue.destinationViewController as! CollectionView

                detailScene.shopzcollection = object as PFObject?

   }


   override func viewDidAppear(animated: Bool) {

        // Refresh the table to ensure any data changes are displayed
        tableView.reloadData();
   }
}`

Collection View Controller :

import UIKit
import Parse
import ParseUI

var shopzcollection = [PFObject]()`

class CollectionView: UIViewController, UICollectionViewDataSource, UICollectionViewDelegate {


// Connection to the collection view
@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLoad() {
    super.viewDidLoad()

}

/*
==========================================================================================
Ensure data within the collection view is updated when ever it is displayed
==========================================================================================
*/

// Load data into the collectionView when the view appears
override func viewDidAppear(animated: Bool) {
    loadCollectionViewData()
}

/*
==========================================================================================
Fetch data from the Parse platform
==========================================================================================
*/

func loadCollectionViewData() {

    // Build a parse query object
    var query = PFQuery(className:"Shopz")


    // Fetch data from the parse platform
    query.findObjectsInBackgroundWithBlock {
        (objects: [PFObject]?, error: NSError?) -> Void in

        // The find succeeded now rocess the found objects into the countries array
        if error == nil {

            // Clear existing data
            shopzcollection.removeAll(keepCapacity: true)

            // Add shop objects to our array
            if let objects = objects as [PFObject]? {
                shopzcollection = Array(objects.generate())
            }

            // reload our data into the collection view
            self.collectionView.reloadData()

        } else {
            // Log details of the failure
            print("Error: \(error!) ")
        }
    }
}

/*
==========================================================================================
UICollectionView protocol required methods
==========================================================================================
*/

func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {
    return 1
}

func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return shopzcollection.count
}

func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("CollectionCell", forIndexPath: indexPath) as! CollectionViewCell

    // Display the country name
    if let value = shopzcollection[indexPath.row]["shopName"] as? String {
        cell.cellTitle.text = value
    }

    if let value = shopzcollection[indexPath.row]["shopAddress"] as? String {
        cell.cellDetail.text = value
    }

    // Fetch final flag image - if it exists

    if let finalImage = shopzcollection[indexPath.row]["imagePromo"] as? PFFile {

        finalImage.getDataInBackgroundWithBlock
            {(imageData: NSData?, error: NSError?) -> Void in
                if error == nil
                {
                    if let imageData = imageData
                    {
                        cell.cellImage!.image = UIImage(data:imageData)
                    }
                }
        }
    }

    return cell
}




/*
==========================================================================================
Process memory issues
To be completed
==========================================================================================
*/

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

}`

我想我必须重新考虑我的代码/项目的结构:

• 使用我的所有变量(shopName、shopAddress、imagePromo)创建一个 swift 文件

• 创建一个用于查询数据的 wife 文件 (query.findObjectsInBackgroundWithBlock)，其中包含要调用的函数，但它涉及更改我的列表 Controller

• 将我的列表归档

• 归档我的收藏
  我只是不知道如何正确调用执行查询的函数...

Answer 1

在 tableViewController 的 prepareForSegue 中，您试图仅传递一个对象(detailScene.shopzcollection = object as PFObject？)。

您应该将整个对象集合 (self.objects) 传递给您的 collectionView。

我不太精通 Swift，但是一个 obj-c 的等价物是:

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    ....
    detailScene.shopzcollection = self.objects;   // shopzcollection is an NSArray in the destination as well
}