Question

我有两个集合视图。点击集合视图1中未选中的单元格将选择它们，并将所选单元格添加到集合视图2.在集合视图1（allHobbiesCV）中点击选定的单元格将取消选择它们并从集合视图2（myHobbiesCV）中删除它们。从本质上讲，它所做的只是切换。

集合视图2中的单元格也可以通过根据需要选择少量或多个来手动删除，然后按“删除”按钮。按钮。此过程非常有效，除非Collection View 1中的单元格仍保持选中状态，即使该特定单元格已从Collection View 2中删除。

如果手动选择并从Collection View 2中删除了单元格，则如何使用“删除”按钮取消选择“集合视图1”中的单元格？

班级 -

var allHobbiesArray = [String]()
var allHobbiesArraySelected = [String]()

var myHobbiesArray = [String]()
var myHobbiesArraySelected = [String]()

didSelectItemAt

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {


    // All Hobbies
    if collectionView == allHobbiesCV {
        let item = allHobbiesArray[indexPath.item]
        let cell = allHobbiesCV.cellForItem(at: indexPath) as! AllHobbiesCell

        if let itemIndex = allHobbiesArraySelected.index(of:item) {
            // DID DESELECT
            allHobbiesArraySelected.remove(at:itemIndex)
            myHobbiesArray.remove(at: itemIndex)
            myHobbiesCV.deleteItems(at: [IndexPath(item: itemIndex, section:0)])
            cell.backgroundColor = UIColor.brown
        }
        else {
            // DID SELECT
            allHobbiesArraySelected.insert(item, at: 0)
            myHobbiesArray.insert(item, at: 0)
            myHobbiesCV.insertItems(at: [IndexPath(item: 0, section:0)])
            cell.backgroundColor = UIColor.green
        }

        allHobbiesCV.deselectItem(at: indexPath, animated: false)

        for cell in myHobbiesCV.visibleCells {
            cell.backgroundColor = UIColor.white
        }
        myHobbiesArraySelected.removeAll()
        //myHobbiesCV.reloadData() // needed?
    }

    // My Hobbies
    else {
        let item = myHobbiesArray[indexPath.item]
        let cell = myHobbiesCV.cellForItem(at: indexPath) as! MyHobbiesCell

        if let itemIndex = myHobbiesArraySelected.index(of:item) {
            // DID DESELECT
            myHobbiesArraySelected.remove(at: itemIndex)
            cell.backgroundColor = UIColor.white
        }
        else {
            // DID SELECT
            myHobbiesArraySelected.insert(item, at: 0)
            cell.backgroundColor = UIColor.red
        }
        myHobbiesCV.deselectItem(at: indexPath, animated: true)
    }
}

cellForItem

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

    if collectionView == allHobbiesCV {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "ALL", for: indexPath) as! AllHobbiesCell
        cell.allHobbiesCellLabel.text = allHobbiesArray[indexPath.item]

        let allHobbies = allHobbiesArray[indexPath.item]
        if allHobbiesArraySelected.index(of: allHobbies) != nil {
            cell.backgroundColor = UIColor.green
        }
        else {
            cell.backgroundColor = UIColor.brown
        }

        return cell
    }

    else { // myHobbiesCV
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "MY", for: indexPath) as! MyHobbiesCell
        cell.myHobbiesCellLabel.text = myHobbiesArray[indexPath.item]

        let myHobbies = myHobbiesArray[indexPath.item]
        if myHobbiesArraySelected.index(of: myHobbies) != nil {
            cell.backgroundColor = UIColor.red
        }
        else {
            cell.backgroundColor = UIColor.white
        }


        return cell
    }

}

numberOfItemsInSection

    if collectionView == allHobbiesCV {
        return allHobbiesArray.count
    }
    else {
        return myHobbiesArray.count
    }

删除按钮

@IBAction func deleteHobbyButtonPressed(_ sender: UIButton) {

    print("all Hobbies - \(allHobbiesCV.indexPathsForSelectedItems!)")

    if let selectedItemPaths = myHobbiesCV.indexPathsForSelectedItems {

        var allItemIndexPaths = [IndexPath]()
        var tempSelectedItems = Array(allHobbiesArraySelected) // Need to use a temporary copy otherwise the element indexes will change
        for itemPath in selectedItemPaths {

            let removeItem = allHobbiesArraySelected[itemPath.item]
            if let removeIndex = tempSelectedItems.index(of: removeItem) {
                print("if let removeIndex")
                tempSelectedItems.remove(at: removeIndex)
            }

            if let allItemsIndex = allHobbiesArray.index(of: removeItem) {
                print("if let allItemsIndex")
                allItemIndexPaths.append(IndexPath(item: allItemsIndex, section: 0))
            }
        }

        allHobbiesArraySelected = tempSelectedItems // Selected items array without the removed items
        myHobbiesCV.deleteItems(at:selectedItemPaths)
        myHobbiesCV.reloadData()
        allHobbiesCV.reloadItems(at: allItemIndexPaths)  // Reload to update the selected status
    }

}

现在的问题是在删除按钮中进行评估。第一个print语句总是返回一个空数组。 if let check中没有任何内容打印出来。有没有办法使用myHobbiesArraySelected而不是indexPathsForSelectedItems？（因为我现在将选定的项目保存在数组中）以及在myHobbiesCV中手动删除的所有HobbiesCV中取消选择单元格的原始预期功能。

谢谢朋友们。

Answer 1

更新： IndexPath符合Equatable （请参阅@ Paulw11的评论） ~~比较IndexPath中的对象contains但是即使indexPath路径的实例具有相同的部分和行，对象本身也是不同的。~~

~~1。解决方案：比较值将包含更改为比较节和行~~

解决方案：坚持使用商品ID 坚持存储在数组中的唯一项ID。如果collection1和collection2具有不同的大小和部分

我建议实施解决方案2

Answer 2

存储选定的索引路径是个坏主意，因为它们会耦合到集合视图。如果存储选定的项，则始终可以使用数组中项的索引来确定相应的索引路径。您还可以从给定的索引路径快速确定项目。

在下面的代码中，我为您的基础项使用了类型{ { "_id": "vehicle1", "vehicleType": "cars", "vehicleId": "car1", "vehicleDetails": { "_id": "car1", "carBrand": "Audi", "color": "" } }, { "_id": "vehicle2", "vehicleType": "cars", "vehicleId": "car2", "vehicleDetails": { "_id": "car2", "carBrand": "BMW", "color": "white" }, { "_id": "vehicle3", "vehicleType": "bikes", "vehicleId": "bike1", "vehicleDetails": { "_id": "bike1", "bikeBrand": "Audi", "color": "red" } }, { "_id": "vehicle4", "vehicleType": "bikes", "vehicleId": "bike2", "vehicleDetails": { "_id": "bike2", "carBrand": "BMW", "color": "white" } }, }，但它可以是Item或String或任何对象类型。如果您使用自己的类或结构，请确保使其符合Int和Equatable。

Hashable

使用按钮取消选择集合视图中的单元格

2 个答案: