在swift中的UiCollectionView中设置单元格的选定颜色

Question

我正在使用collectionview来显示数据。

每个单元格的选定和未选择颜色都在那里

但我想在collectionview中设置第一个单元格的默认颜色。

如果有10个数据。我的第一个单元格应该像截图

如何实现这一目标？ 当我在indexpath设置颜色时会出现此问题

Answer 1

对于基于单元格选定状态的两种不同颜色，您可能需要子类化您的UICollectionViewCell，如下所示：

import UIKit 

class YourCollectionViewCell: UICollectionViewCell {

    @IBOutlet weak var imageView: UIImageView! // for example - some UI element inside cell ...

    override var isSelected: Bool {
        didSet {
            self.contentView.backgroundColor = isSelected ? UIColor.blue : UIColor.yellow
            self.imageView.alpha = isSelected ? 0.75 : 1.0
        }  
      }
    }


// and below you will have your original code

class YourViewController: UICollectionViewController {

... etc

回答你的问题 - 第一个单元格的特殊风格：

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCell ... 

        if(indexPath.row == 0) { //for first cell in the collection
            cell.backgroundColor = UIColor.orange
        } else {
            cell.backgroundColor = UIColor.green
        }

Answer 2

这是我的问题代码。希望能为您节省时间：）

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
            let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "customCell", for: indexPath) as! CustomCell
            if let indexPaths = collectionView.indexPathsForSelectedItems, let indexP = indexPaths.first {
                cell.bgView.backgroundColor = indexP == indexPath ? .white : .lightGray
            }
            return cell }
 func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
            if let cell = collectionView.cellForItem(at: indexPath) as? CustomCell {
                cell.bgView.backgroundColor = .white }
        }
func collectionView(_ collectionView: UICollectionView, didDeselectItemAt indexPath: IndexPath) {
        guard let cell = collectionView.cellForItem(at: indexPath) as? CustomCell else {
                return
        }
        cell.bgView.backgroundColor = .lightGray

    }

Answer 3

调用selectItemAtIndexPath：animated：scrollPosition：UICollectionView的reloadData方法之后的方法

e.g。

let collectionView = UICollectionView()
collectionView.reloadData()     
collectionView.selectItemAtIndexPath(NSIndexPath(forItem: 0, inSection: 0), animated: true, scrollPosition: .None)

Answer 4

根据@ pedroun的回答，这是我更新的答案，以制作您的第一个单元格的默认颜色。希望这会对你有所帮助。

 $(document).ready(function() {
$(document).on('click', '#new_topic', function() {
console.log("SONO DENTRO");
$('ul[class="formatting-group"]').append('<li tabindex="-1" data-format="schedula" title="Schedula Topic"><i class="fa fa-calendar" aria-hidden="true"></i></li>');
                    });
                });

对于@IBOutlet weak var cellImageview: UIImageView! var cellIndex: Int? { didSet { guard let index = cellIndex else { return } if index != 0 { contentView.backgroundColor = UIColor.blueColor()//change this to your unselected cell color. }else{ contentView.backgroundColor = UIColor.redColor()//this is default color for your first cell. cellImageview.alpha = 1.0 } } } override var selected: Bool { didSet { contentView.backgroundColor = selected ? UIColor.redColor(): UIColor.blueColor()//change colors as per your requirements cellImageview.alpha = selected ? 0.75 : 1.0 } } 媒体资源，您需要在cellIndex中将其设置为cellForRowAtIndexPath

Answer 5

UICollectionViewDelegate中有两个委托方法。

didDeselectItemAtIndexPath＆amp; didSelectItemAtIndexPath

单击集合单元格时，可以获取单元格的indexPath。您可以使用cellForItemAtIndexPath

获取集合单元格

我在UITableView中经历过，我认为UICollectionView与以下逻辑相同。

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
    if indexPath.row < arrData.count && arrData.count > 0{
        if let selectedCell = tableView.cellForRowAtIndexPath(indexPath) as? GARatesCell {
        selectedCell.viewBG.backgroundColor = COLOR_NAV_BAR
        selectedCell.lblTitle.textColor = UIColor.whiteColor()
        btnShare.backgroundColor = COLOR_NAV_BAR
        self.selectedIndex = indexPath.row
        }
    }
}

func tableView(tableView: UITableView, didDeselectRowAtIndexPath indexPath: NSIndexPath) {

    if  indexPath.row < arrData.count && arrData.count > 0{
        let deselectedCell = tableView.cellForRowAtIndexPath(indexPath) as? GARatesCell
        if deselectedCell != nil {
            deselectedCell?.viewBG.backgroundColor =  COLOR_BG_BAR
            deselectedCell?.lblTitle.textColor = COLOR_NAV_BAR
        }
    }

}

Answer 6

我知道这不是一个完美的解决方案。但这是可行的。

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    collectionView.visibleCells.forEach {
        $0.backgroundColor = .white
    }
}