每个 TableView 单元格都会更新，而不仅仅是被点击的单元格. [英] every TableView Cell updated instead of just one that is clicked.

问题描述

我有两个按钮(喜欢/不喜欢)，它们的工作方式类似于大拇指向上和向下投票系统的风格.但是，当我单击按钮时，每个单元格都会更新.有没有办法解决这个问题，以便只有被点击的人才能更新?

I have two Buttons (like/dislike) that works like thumbs up and down voting system style. When I click on the button though, every cell gets updated. Is there a way to solve this so that only the one that gets clicked updated?

另外，如何重新加载单元格，以便我不必拉刷新来更新 button.setTitle 值的值?

Also, How do I reload the cell so that I don't have to pull to refresh to update the value of the button.setTitle value?

这是我的代码:

PFTableViewCell:

class UserFeedCell: PFTableViewCell {

@IBOutlet weak var likeButton: UIButton!
@IBOutlet weak var dislikeButton: UIButton!


var vote: Int = 0 // initialize to user's existing vote, retrieved from the server
var likeCount: Int = 0 // initialize to existing like count, retrieved from the server
var dislikeCount: Int = 0 // initialize to existing dislike count, retrieved from the server

@IBAction func dislikeButton(sender: UIButton) {
buttonWasClickedForVote(-1)
print(likeCount)
print(dislikeCount)

}

@IBAction func likeButton(sender: UIButton) {
buttonWasClickedForVote(1)
print(likeCount)
print(dislikeCount) 

}

private func buttonWasClickedForVote(buttonVote: Int) {
if buttonVote == vote {
    // User wants to undo her existing vote.
    applyChange(-1, toCountForVote: vote)
    vote = 0
}

else {
    // User wants to force vote to toggledVote.
    // Undo current vote, if any.
    applyChange(-1, toCountForVote: vote)

    // Apply new vote.
    vote = buttonVote
    applyChange(1, toCountForVote: vote)
}

}

private func applyChange(change: Int, toCountForVote vote: Int ) {
if vote == -1 { dislikeCount += change }
else if vote == 1 { likeCount += change }

}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cellIdentifier = "TableViewCell" // your cell identifier name in storyboard 
let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier, forIndexPath: indexPath) as! PFTableViewCell
cell.likeButton.selected = vote == 1
cell.dislikeButton.selected = vote == -1
cell.likeButton.titleLabel!.text = "\(likeCount)"
cell.dislikeButton.titleLabel!.text = "\(dislikeCount)"
return cell

}

推荐答案

你可以用委托机制来做

为您的操作创建protocol:

 protocol LikeProtocol {
        func likeOrDislikeActionAtRow(row: Int)
    }

让你的 TableViewController 类确认这个协议:

Make your TableViewController class confirm this protocol:

class YourTableViewController: UITableViewController, LikeProtocol {
    ...
    func likeOrDislikeActionAtRow(row: Int) {
        ...
        // Reload only you want cell
        self.tableView.beginUpdates()
        self.tableView.reloadRowsAtIndexPaths([NSIndexPath(forRow: row, inSection: 1)], withRowAnimation: UITableViewRowAnimation.Fade)
        self.tableView.endUpdates()
        ...
    }
    ...
}

添加到您的 PFTableViewCell 委托对象，类型为 protocol 和 row 变量:

Add to your PFTableViewCell delegate object with type on protocol and row variable:

var delegate: LikeProtocol?
var rowValue: Int?

在您的 func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) 处设置委托和行:

cell.delegate = self
cell.row = indexPath.row

在喜欢和不喜欢的动作中调用协议方法:

Call protocol method in your like and dislike actions:

@IBAction func likeButton(sender: UIButton) {
    ....
    delegate!.likeOrDislikeActionAtRow(row!)
    ....
}

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