如何更改单击按钮的图像？

Question

我在自定义单元格中有一个按钮的预设图像，我希望该图像在单击按钮时发生变化。 我该怎么做？ 我在按钮上放了一个开关，它起作用了。 单击它时会播放一首歌曲，再次单击时它将停止播放。 我只想改变图像。 我该怎么做？ 按钮的名称是playbutton 。

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {


    let cell = friendstable.dequeueReusableCellWithIdentifier("friendcell", forIndexPath: indexPath) as! FriendsMusicCell


    cell.playbutton.tag = indexPath.row
    cell.playbutton.addTarget(self, action: "playmusic:", forControlEvents: .TouchUpInside)

    cell.customtitle.text = titleofsong[indexPath.row]
    cell.customartist.text = artist[indexPath.row]
    cell.customtitle.font = UIFont(name: "Lombok", size: 22)
    cell.customtitle.textColor =  UIColorFromRGB("4A90E2")
    cell.customartist.font = UIFont(name: "Lombok", size: 16)
    cell.customartist.textColor =  UIColor.blackColor()

    cell.customtitle.numberOfLines = 0;
    cell.textLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping

    cell.backgroundColor = UIColor.clearColor()



    return cell
}


func playmusic(sender: UIButton!) {

    let playButtonrow = sender.tag
    print(titleofsong[playButtonrow])
    switch(buttonState){
    case 0:
    let searchTerm: String = titleofsong[playButtonrow]

    let itunesSearchTerm = searchTerm.stringByReplacingOccurrencesOfString(" ", withString: "+", options: NSStringCompareOptions.CaseInsensitiveSearch, range: nil)

    if let escapedSearchTerm = itunesSearchTerm.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding) {
        let urlPath = "https://itunes.apple.com/search?term=\(escapedSearchTerm)&media=music"
        let url: NSURL = NSURL(string: urlPath)!


        print("Search iTunes API at URL \(url)")

        let task = NSURLSession.sharedSession().dataTaskWithURL(url) {(data, response, error) -> Void in
            do {
                if let dict: NSDictionary = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as? NSDictionary
                {


                    let previewUrl = NSURL(string: (dict["results"]![0]["previewUrl"] as? String)!)!
                    print(previewUrl)
                    self.player = AVPlayer(URL: previewUrl)
                    self.player.rate = 1.0
                    self.player.play()



                }

            } catch let jsonError as NSError {

                }
            }
        task.resume()

        }
    buttonState = 1;
    break;
    case 1:
        player.pause()

        buttonState = 0;
    default: break

    }
}

Answer 1

您不需要全局声明 playButton

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {


let cell = friendstable.dequeueReusableCellWithIdentifier("friendcell", forIndexPath: indexPath) as! FriendsMusicCell


cell.playbutton.tag = indexPath.row
cell.playButton.setImage(playImage, forState: UIControlState.Normal) 
cell.playButton.setImage(pauseImage, forState: UIControlState.Selected)
cell.playbutton.addTarget(self, action: "playmusic:", forControlEvents: .TouchUpInside)

cell.customtitle.text = titleofsong[indexPath.row]
cell.customartist.text = artist[indexPath.row]
cell.customtitle.font = UIFont(name: "Lombok", size: 22)
cell.customtitle.textColor =  UIColorFromRGB("4A90E2")
cell.customartist.font = UIFont(name: "Lombok", size: 16)
cell.customartist.textColor =  UIColor.blackColor()

cell.customtitle.numberOfLines = 0;
cell.textLabel?.lineBreakMode = NSLineBreakMode.ByWordWrapping

cell.backgroundColor = UIColor.clearColor()



return cell
}

在您的播放音乐功能中，您可以在开头添加以下行

sender.selected = !sender.selected

Answer 2

它是如此容易。 您可以使用 UIControlState ex 为 uibutton 设置图像：

self.btnPlay.setImage(playImage, forState: UIControlState.Normal)
self.btnPlay.setImage(pauseImage, forState: UIControlState.Selected)

当你点击它时，你会改变 btnPlay 的状态：

self.btnPlay.selected = !self.btnPlay.selected