Question

代码是用Swift编写的。我正在构建一个用户可以发帖的社交应用。我正在使用Firebase作为后端（数据库，存储）。所以，我有一个UICollectionView来获取设备照片库中的所有照片，并使用自定义单元格填充集合视图。在同一个View控制器中，我有另一个自定义单元格，用户可以使用它来拍照并使用它来发布帖子。为了更清楚：

如果用户决定拍照，当他们点击“使用照片”时，他们需要被呈现给新的视图控制器，该控制器应显示他们刚拍摄的照片以及其他选项（例如标题，使用UITextFields＆amp; UITextView）的说明和标签。
如果用户决定从他们自己的库中选择多张照片，我必须以某种方式标记这些照片/单元格（即使用复选标记按钮），将所选照片添加到数组中（有一些限制，也许10张照片顶部）。当他们单击“下一步”按钮时，需要将数组发送到新的后视图控制器，其中所有图像都应该动态显示，可能使用水平UICollectionView（？！）（如果选择删除图像，它是偶然选择的）如上所述，再次有机会添加标题，描述等。现在，我无法弄清楚如何做到这一点。

我找了一个解决方案，但我现在已经坚持了几天了，所以非常欢迎帮助！

这是我在集合视图控制器中的内容（PS：我没有包含带有从照片中获取图像的功能的部分）

import UIKit
import Photos

class PrePhotoPostVC: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource, UINavigationControllerDelegate, UIImagePickerControllerDelegate, UICollectionViewDelegateFlowLayout {

@IBOutlet weak var nextButton: UIBarButtonItem!
var photosLibraryArray = [UIImage]()

@IBOutlet weak var collectionView: UICollectionView!

override func viewDidLoad() {
    super.viewDidLoad()

    checkPhotoLibraryPermission()
    setupCollectionViewDelegates()
}

@IBAction func cancelButtonPressed (_ sender: UIBarButtonItem) {
    dismiss(animated: true, completion: nil)
}

@IBAction func nextButtonPressed (_ sender: UIBarButtonItem) {
    nextButton.isEnabled = false
}

@IBAction func takeAphotoButtonPressed (_ sender: UIButton) {

    // Camera Autorization
    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { response in
        if response {
            if UIImagePickerController.isSourceTypeAvailable(UIImagePickerControllerSourceType.camera) {
                let imagePicker = UIImagePickerController()
                imagePicker.delegate = self
                imagePicker.sourceType = UIImagePickerControllerSourceType.camera;
                imagePicker.allowsEditing = false
                self.present(imagePicker, animated: true, completion: nil)
            }
            else {
                print("Camera isn't available in similator")
            }
        }
        else {
            print("unautorized")
        }
    }
}

 func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 2
}
 func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    if section == 0 {
        return 1
    } else {
        return photosLibraryArray.count
    }
 }

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

    if indexPath.section == 0 {
        let cellCamera = collectionView.dequeueReusableCell(withReuseIdentifier: cellPrePostCameraCell, for: indexPath) 
        return cellCamera
    }
    else {
        let cellPhotoLibrary = collectionView.dequeueReusableCell(withReuseIdentifier: cellPrePostPhotoLibrary, for: indexPath) as! PrePhotoPostPhotoLIbraryCell
        cellPhotoLibrary.awakeFromNib()
        cellPhotoLibrary.photoLibraryImage.image = photosLibraryArray[indexPath.row]
        return cellPhotoLibrary
    }
}
}

此UICollectionView的截图：

这是我在照片库单元格中的代码：

import UIKit

class PrePhotoPostPhotoLIbraryCell: UICollectionViewCell {

    // MARK: Outlets
    @IBOutlet weak var photoLibraryImage: UIImageView!

    // var selectedPhotos = [UIImageView]()

    @IBAction func selectedButtonPressed(_ sender: UIButton) {
        self.layer.borderWidth = 3.0
        self.layer.borderColor = isSelected ? UIColor.blue.cgColor : UIColor.clear.cgColor
    }
    override func awakeFromNib() {

        photoLibraryImage.clipsToBounds = true
        photoLibraryImage.contentMode = .scaleAspectFill
        photoLibraryImage.layer.borderColor = UIColor.clear.cgColor
        photoLibraryImage.layer.borderWidth = 1
        photoLibraryImage.layer.cornerRadius = 5

    }
}

Answer 1

首先声明一个可变类型数组，用于存储所选单元格项目。

var _selectedCells : NSMutableArray = []

然后在 viewDidLoad 功能中添加以下代码。

 override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        //this will allow multiple selection on uicollectionviewcell
        CollectionView.allowsMultipleSelection=true //CollectionView is your CollectionView outlet
}

然后，实现collectionview的委托函数以选择和取消选择单元格

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

        //add the selected cell contents to _selectedCells arr when cell is selected
        _selectedCells.add(indexPath)
        collectionView.reloadItems(at: [indexPath])
    }

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

        //remove the selected cell contents from _selectedCells arr when cell is De-Selected

        _selectedCells.remove(indexPath)
        collectionView.reloadItems(at: [indexPath])
    }

我建议将所选项目的NSIndexPath保存在数组中，然后在委托函数cellForItemAt indexPath中使用它作为比较基础。

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

let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "YOUR_CELL_Identifier", for: indexPath as IndexPath)

//add your tick mark image to the cell in your storyboard or xib file.
let tickImage = cell.viewWithTag(YOUR_IMAGE_TAG_HERE) as? UIImageView

//Show tickImage if the cell is selected and hide tickImage if cell is NotSelected/deSelected.or whatever action you want to perform in case of selection and deselection of cell.

if _selectedCells.contains(indexPath) {
cell.isSelected=true
collectionView.selectItem(at: indexPath, animated: true, scrollPosition: UICollectionViewScrollPosition.top)
tickImage?.isHidden=false
}
else{
cell.isSelected=false
tickImage?.isHidden=true
}
return cell
}

为了将项目发送到下一个控制器，从所选索引路径中获取所有项目。

如何从UICollectionView中选择多个图像并将它们传输到另一个View Controller？

1 个答案: