Call batch updates with TableView

问题

With a collection I would perform batch updates to prevent it from flashing...Now I'm trying to do the same with a table, if possible...

In a previous post I did it as the answer shows....CollectionView flash when reloadData

here's my query, as I think I need to add it in there:

let query = PFQuery(className: "Posts")
query.limit = self.page
query.addDescendingOrder("createdAt")
query.whereKey("username", notContainedIn: self.followArray)
query.whereKey("username", notEqualTo: PFUser.currentUser()!.username!)
query.findObjectsInBackgroundWithBlock ({ (objects:[PFObject]?, error:NSError?) -> Void in

    if error == nil {
        //let oldUUIDArray = self.uuidArray
        self.images.removeAll(keepCapacity: false)
        self.tableData.removeAll(keepCapacity: false)


        for object in objects! {

            if let _ = object.valueForKey("textPost") as? PFFile {
                // this must be a text post
                let post = ImageStruct(dataTypeInit: 0,
                    uuidInit: object.valueForKey("uuid") as! String,
                    textInit: object.valueForKey("textPost") as! PFFile)


               self.images.append(post)
            } else {
                // this must be an image
                    // this must be a text post
                    let post = ImageStruct(dataTypeInit: 1,
                        uuidInit: object.valueForKey("uuid") as! String,
                        imageInit: object.valueForKey("image") as! PFFile)


                    self.images.append(post)
            }}
        self.tableView1.reloadData()
    }

If anyone can help me change it from batch updates to the tableView version that would be great....

回答1:

let query = PFQuery(className: "Posts")
query.limit = self.page
query.addDescendingOrder("createdAt")
query.whereKey("username", notContainedIn: self.followArray)
query.whereKey("username", notEqualTo: PFUser.currentUser()!.username!)
query.findObjectsInBackgroundWithBlock ({ (objects:[PFObject]?, error:NSError?) -> Void in

    if error == nil {
        let oldImageArray = self.images
        self.images.removeAll(keepCapacity: false)
        self.tableData.removeAll(keepCapacity: false)
        let oldImageArray = self.images

        for object in objects! {

            if let _ = object.valueForKey("textPost") as? PFFile {
                // this must be a text post
                let post = ImageStruct(dataTypeInit: 0,
                    uuidInit: object.valueForKey("uuid") as! String,
                    textInit: object.valueForKey("textPost") as! PFFile)


               self.images.append(post)
            } else {
                // this must be an image
                    // this must be a text post
                    let post = ImageStruct(dataTypeInit: 1,
                        uuidInit: object.valueForKey("uuid") as! String,
                        imageInit: object.valueForKey("image") as! PFFile)


                    self.images.append(post)
            }}
        let newImageUUIDArray = self.images.map({return $0.uuid})
        let oldImageUUIDArray = oldImageArray.map({return $0.uuid})
        let oldImageSet = Set(oldImageUUIDArray)
        let newImageSet = Set(newImageUUIDArray)
        let missingImages = newImageSet.subtract(oldImageSet)

        let missingImageIndexPaths = Array(missingImages).map{NSIndexPath(forRow:newImageUUIDArray.indexOf($0)!,inSection:0)}

        let removedImages = oldImageSet.subtract(newImageSet)
        let removedImageIndexPaths = Array(removedImages).map{NSIndexPath(forRow:oldImageUUIDArray.indexOf($0)!,inSection:0)}



     self.tableView1.beginUpdate()
            if missingImageIndexPath.count != 0 {
       self.tableView1.insertRowsAtIndexPaths(missingImageIndexPaths,withRowAnimation:.Right)
}
            if removedImageIndexPath.count != 0 {
              self.tableView1.deleteRowsAtIndexPaths(removedImageIndexPaths,withRowAnimation:.Fade)
}
            self.tableView1.endUpdates()
        }

You could factor the determining of new image and deleted image index paths into other functions to make it more readable. But in general this will only update rows that have changed rather than reloading all of the data.

来源：https://stackoverflow.com/questions/36043809/call-batch-updates-with-tableview