在第一个collectionview单元格中快速添加相机预览

如何解决在第一个collectionview单元格中快速添加相机预览

我想在第一个collectionCell中放置一个摄像机预览（就像Telegram一样）（而其他单元格中充满了来自画廊的照片）。当用户点击第一个单元格时，我需要显示一个摄像头。但是，当我点击单元格时，我在xCode中没有任何信息就崩溃了。

name: .NET Core

on:
  push:
    branches: [ master ]
  pull_request:
    branches: [ master ]

jobs:
  build:

    runs-on: windows-latest

    steps:
    - name: Checkout
      uses: actions/checkout@v2
    
    - name: Setup .NET Core
      uses: actions/setup-dotnet@v1.5.0
      with:
        dotnet-version: 3.1.301
        # Authenticates packages to push to GPR
        source-url: https://nuget.pkg.github.com/${{ github.repository_owner }}/index.json
      env:
        NUGET_AUTH_TOKEN: '%NUGET_AUTH_TOKEN%'
    
    - name: Setup MSBuild
      uses: microsoft/setup-msbuild@v1.0.1
    
    - name: Install dependencies
      run: msbuild /t:Restore
      env:
        NUGET_AUTH_TOKEN: ${{ github.token }}
    
    - name: Build
      run: msbuild /t:Pack /p:Configuration=Debug Library/MintPlayer.MVVM/MintPlayer.MVVM.csproj
    
    - name: PushNuget
      run: dotnet nuget push "**/*.nupkg" --source https://api.nuget.org/v3/index.json --api-key ${{ secrets.PUBLISH_TO_NUGET_ORG }} --skip-duplicate
    
    - name: PushGithub
      run: nuget.exe push "**/*.nupkg" -NoSymbols -SkipDuplicate
      env:
        NUGET_AUTH_TOKEN: ${{ github.token }}

在这种情况下，如果我点击第一个单元格，则相机会正常显示，但是当我在单元格中添加相机预览时，相机视图将不再显示

let cameraPicker: UIImagePickerController = {
    let picker = UIImagePickerController()
    picker.sourceType = .camera
    picker.cameraDevice = .front
    picker.showsCameraControls = false
    return picker
}()
override func viewDidLoad() {
    super.viewDidLoad()
    imageCollectionView.delegate = self
    imageCollectionView.dataSource = self
    if UIImagePickerController.isCameraDeviceAvailable(.front) {
        cameraPicker.delegate = self
        //my cell size
        let screenSize = CGSize(width: 80,height: 80)
        let cameraAspectRatio = CGFloat(4.0 / 3.0)
        let cameraImageHeight = screenSize.width * cameraAspectRatio
        let scale = screenSize.height / 40
        cameraPicker.cameraViewTransform = CGAffineTransform(translationX: 0,y: (screenSize.height - cameraImageHeight)/2)
        cameraPicker.cameraViewTransform = cameraPicker.cameraViewTransform.scaledBy(x: scale,y: scale)
    
        cameraPicker.view.frame = CGRect(x: 0,y: 0,width: screenSize.width,height: screenSize.height)
    }

func collectionView(_ collectionView: UICollectionView,willDisplay cell: UICollectionViewCell,forItemAt indexPath: IndexPath) {
    guard let cell = cell as? PSTBaseImageCollectionViewCell else { return  }
    cell.imageView.subviews.forEach{$0.removeFromSuperview()}
    cell.imageView.image = nil
    if indexPath.row == 0 {
        
    } else {
        let asset = allPhotos?.object(at: indexPath.row - 1)
        cell.imageView.fetchImageFromAsset(asset: asset!,contentMode: .aspectFill,targetSize: CGSize(width: asset!.pixelWidth,height: asset!.pixelHeight))
    }
}
    func collectionView(_ collectionView: UICollectionView,didSelectItemAt indexPath: IndexPath) {
    if indexPath.row == 0 {
        if UIImagePickerController.isSourceTypeAvailable(.camera) {
            cameraPicker.showsCameraControls = true
            present(cameraPicker,animated: true)
        }
    }
}

我想念什么？

解决方法

为什么要使用willDisplay设置单元格？

https://developer.apple.com/documentation/uikit/uicollectionviewdelegate/1618087-collectionview?language=objc

“讨论 集合视图在将单元格添加到其内容之前调用此方法。使用这种方法来检测单元格的增加，而不是监视单元格本身以查看它何时出现。”

使用此命令：https://developer.apple.com/documentation/uikit/uicollectionviewdatasource/1618029-collectionview

,

我可能为时已晚，但我找到了解决方案。 我在我的应用程序中做了同样的事情，但我添加了一个 UIView 并将其 isUserInteractionEnabled 设置为 false，而不是图像视图

在 cellForRowAt 中：

if indexPath.row == 0 {
    cell.preview.addSubview(cameraPicker.view)
    cameraPicker.view.frame = cell.imageView.bounds
    cell.preview.isUserInteractionEnabled = false
} else {
    let asset = allPhotos?.object(at: indexPath.row - 1)
    cell.imageView.fetchImageFromAsset(asset: asset!,contentMode: .aspectFill,targetSize: CGSize(width: asset!.pixelWidth,height: asset!.pixelHeight))
}

我在单元格中仍然有一个 imageView，但这只是为了显示带有我的应用程序徽标的渐变色调（alpha 设置为 0.3），使其看起来像一个叠加

编辑：我还意识到您从未为相机预览设置框架