Question

我想只重新加载选定的单元格，特别是在单元格中点击图片时。但是我得到的错误是无法在此行将类型'IndexPath.Type'的值转换为预期的参数类型'IndexPath'：loadPostsValue（indexPath ：IndexPath）

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        let indexPath = self.collectionView.indexPathsForSelectedItems
        print(indexPath)
        loadPostsValue(indexPath: IndexPath)
    }

    func loadPostsValue(indexPath: IndexPath) {
        posts.removeAll()
        let ref = Database.database().reference()
        ref.child("posts").observe(.childAdded) { (snapshot: DataSnapshot) in
            if  let dict = snapshot.value as? [String: Any] {
                guard let titleText = dict["title"] as? String else{return}
                let locationDetails = dict["location"] as! String
                let captionText = dict["caption"] as! String
                let photoUrlString = dict["photoUrl"] as! String
                let priceText = dict["price"] as! String
                let categoryText = dict["category"] as! String
                let usernameLabel = dict["username"] as! String
                let profileImageURL = dict["pic"] as! String
                let heartInt = dict["heart"] as! Int
                let timestampString = dict["timestamp"] as! String
                let post = Post(titleText: titleText, captionText: captionText, locationDetails: locationDetails, photoUrlString: photoUrlString, priceText: priceText,categoryText: categoryText, usernameLabel: usernameLabel, profileImageURL: profileImageURL, heartInt: heartInt, timestampString: timestampString)
                self.posts.append(post)
                print(self.posts)
                self.collectionView.reloadItems(at: [indexPath])


            }
        }
    }

Answer 1

您应按如下所示提供所需的indexPath，

if let indexPath = self.collectionView.indexPathsForSelectedItems?.first {
    print(indexPath)
    loadPostsValue(indexPath: indexPath)
}

当前，您没有传递IndexPath的对象，而是传递了Type抱怨的compiler的对象。另外，indexPathsForSelectedItems是所有选定项的array，因此如果您的indexPath的多项选择已关闭，则应该检索第一个collectionView。

编辑，我认为一种简单的方法是当您已经从委托方法本身中选择了indexPathsForSelectedItems时不使用indexPath。您只需将其传递如下，

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

正如您在评论中提到的那样，我认为如果您只想更新点赞次数，可以按以下步骤操作

func loadPostsValue(indexPath: IndexPath) {
    let ref = Database.database().reference()
    ref.child("posts").observe(.childAdded) { (snapshot: DataSnapshot) in
        if let dict = snapshot.value as? [String: Any] {
            guard let titleText = dict["title"] as? String else{ return }
            let post = self.posts[indexPath.row]
            post.heartInt = dict["heart"] as! Int
            self.collectionView.reloadItems(at: [indexPath])
        }
    }
}

无法仅重新加载选定的单元格

1 个答案: