Can't reverse table view

Question

I tried to reverse my table view in the view did load method by reversing the arrays but it's not working. I'm trying to make it so that it sorts the feed from the time it was created from top to bottom. Am I doing it wrong? If so what should I do?

class Feed: UIViewController, UITableViewDelegate, UITableViewDataSource {

@IBOutlet var table: UITableView!

@IBOutlet var feedBar: UINavigationBar!

var titles = [String]()
var messages = [String]()
var usernames  = [String]()
var types = [String]()

override func viewDidLoad() {
    super.viewDidLoad()
    table.dataSource = self
    messages.reverse()
    titles.reverse()
    usernames.reverse()
    types.reverse()
}

func UIColorFromRGB(rgbValue: UInt) -> UIColor {
    return UIColor(
        red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
        green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
        blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
        alpha: CGFloat(1.0)
    )
}


override func viewDidAppear(animated: Bool) {
    println("View appeared")

    self.messages.removeAll(keepCapacity: true)
    self.titles.removeAll(keepCapacity: true)
    self.usernames.removeAll(keepCapacity: true)
    self.types.removeAll(keepCapacity: true)

    var postQuery = PFQuery(className: "Post")

    postQuery.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in

        if let objects = objects {

            for object in objects {

                self.messages.append(object["message"] as! String)

                self.titles.append(object["title"] as! String)

                self.usernames.append(object["username"] as! String)

                self.types.append(object["type"] as! String)

                self.table.reloadData()


            }

        }

    })
}


func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
    let postCell = tableView.dequeueReusableCellWithIdentifier("feedPost", forIndexPath: indexPath) as! PostCell

    var post = PFObject(className: "Post")

    if messages.isEmpty == false {
        postCell.message.text = messages[indexPath.row]
    }

    if titles.isEmpty == false {
        postCell.postTtitle.text = titles[indexPath.row]
    }

    if usernames.isEmpty == false {
        postCell.posterName.setTitle(usernames[indexPath.row], forState: .Normal)
    }

    if self.types[indexPath.row] == "post1" {
        postCell.sideLeft.backgroundColor = self.UIColorFromRGB(0xFCFFBD)
        postCell.sideRight.backgroundColor = self.UIColorFromRGB(0xFCFFBD)

    } else if self.types[indexPath.row] == "post2" {
        postCell.sideLeft.backgroundColor = self.UIColorFromRGB(0xFFB4AC)
        postCell.sideRight.backgroundColor = self.UIColorFromRGB(0xFFB4AC)

    } else if self.types[indexPath.row] == "post3" {
        postCell.sideLeft.backgroundColor = self.UIColorFromRGB(0xFFD5A4)
        postCell.sideRight.backgroundColor = self.UIColorFromRGB(0xFFD5A4)
    }


    postCell.selectionStyle = .None

    postCell.message.scrollRangeToVisible(NSMakeRange(0, 0))

    return postCell

}

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

}

This stuff may help you, its in Objective C. But you will get idea https://github.com/rcmcastro/whatsapp-ios — Shebin Koshy, Sep 07 '15 at 04:05

score 0 · Answer 1 · answered Sep 07 '15 at 04:06

0

Observe that in the view's life cycle the viewDidAppear gets called after your viewDidLoad method. It appears that you try to reload the contents from within your viewDidAppear method, and there you are clearing those arrays which you had reversed earlier in viewDidLoad. This is the reason why you are not seeing any effect. You might want to reverse your arrays there.

answered Sep 07 '15 at 04:06

Shripada

6,296
1
30
30

Do you see the arrays getting populated in that postQuery.findObjectsInBackgroundWithBlock? – Shripada Sep 07 '15 at 04:18
Yes I do, I just want it to get populated the other way, like most social media feeds. – Ethan Cotler Sep 07 '15 at 04:23

score 0 · Answer 2 · answered Sep 07 '15 at 04:08

0

You are reversing array in viewDidLoad, but you append something in viewDidAppear. viewDidAppear call after viewDidLoad. You should reverse array in the end of viewDidAppear before call self.table.reloadData()

override func viewDidAppear(animated: Bool) {
    println("View appeared")

    self.messages.removeAll(keepCapacity: true)
    self.titles.removeAll(keepCapacity: true)
    self.usernames.removeAll(keepCapacity: true)
    self.types.removeAll(keepCapacity: true)

    var postQuery = PFQuery(className: "Post")

    postQuery.findObjectsInBackgroundWithBlock({ (objects, error) -> Void in

        if let objects = objects {

            for object in objects {

                self.messages.append(object["message"] as! String)

                self.titles.append(object["title"] as! String)

                self.usernames.append(object["username"] as! String)

                self.types.append(object["type"] as! String)




            }
            messages.reverse()
            titles.reverse()
            usernames.reverse()
            types.reverse()
            self.table.reloadData()
        }
    })
}

answered Sep 07 '15 at 04:08

tuledev

10,177
4
29
49

I just tried this and it didn't work. I'm not sure why. – Ethan Cotler Sep 07 '15 at 04:12
Can you print out `messages` ? – tuledev Sep 07 '15 at 04:19
Should I print it in the cellForRowAtIndexPath method or the view did appear method? – Ethan Cotler Sep 07 '15 at 04:22
`viewDidAppear` and cellForRowAtIndexPath also – tuledev Sep 07 '15 at 04:23
This is the log I got... [This is the message] [This is the message, This is another message] [This is the message, This is another message, This is another, other message] [This is the message, This is another message, This is another, other message] [This is the message, This is another message, This is another, other message] – Ethan Cotler Sep 07 '15 at 04:27
The log is before `messages.reverse()` ? right? call it after `messages.reverse()` in `viewDidAppear ` – tuledev Sep 07 '15 at 04:31
I did call it after but for some reason it didn't reverse. – Ethan Cotler Sep 07 '15 at 04:33
I think the problem with reverse() method. Can you try `messages = messages.reverseObjectEnumerator().allObjects`? – tuledev Sep 07 '15 at 04:36
I just tried that and it says that it doesn't contain that member. – Ethan Cotler Sep 07 '15 at 04:44

score 0 · Answer 3 · answered Sep 07 '15 at 05:22

0

I figured it out what I did was I did this instead of append...

self.messages.insert(object["message"] as! String, atIndex: 0)

What this basically does is appends the newest message to the beginning of the array.

answered Sep 07 '15 at 05:22

Ethan Cotler

57
8

Can't reverse table view

3 Answers3