swift - 带有 SDWebImage 的 JSQMessagesViewController 中的用户特定头像

Question

正如标题所暗示的，我正在使用 JSQMessagesViewController。我希望每个用户都有自己的 Avatar [UIImage] 从 FirebaseDatabase 中的 URL 获取它并通过提取它。 SDWeb 图像。我能把这个放进去；

override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = super.collectionView(collectionView, cellForItemAt: indexPath) as! JSQMessagesCollectionViewCell

    let message = messages[indexPath.item]

    if let messageID = message.senderId {
        rootRef.child("users").child(messageID).observe(.value, with: { (snapshot) in

            if let profileURL = (snapshot.value as AnyObject!)!["profileURL"] as! String! {
                let profileNSURL: NSURL = NSURL(string: profileURL)!
                cell.avatarImageView.sd_setImage(with: profileNSURL as URL)
            }
        })
    }
            return cell
}

但是，每次您发送消息并重新加载表格时，图像都会消失然后重新出现，因为我假设它会再次通过所有索引路径。

下面是处理头像数据源的方法；

override func collectionView(_ collectionView: JSQMessagesCollectionView!, avatarImageDataForItemAt indexPath: IndexPath!) -> JSQMessageAvatarImageDataSource! {
 return ???????????????????????????????????????
}

但似乎无法组织与 cellForItemAt 中相同的逻辑？谁能帮忙？...非常感谢。

更新:- ******************************************** **********************

override func collectionView(_ collectionView: JSQMessagesCollectionView!, avatarImageDataForItemAt indexPath: IndexPath!) -> JSQMessageAvatarImageDataSource! {

    let placeHolderImage = UIImage(named: "Circled User Male Filled-25")
    let avatarImage = JSQMessagesAvatarImage(avatarImage: nil, highlightedImage: nil, placeholderImage: placeHolderImage)

    let message = messages[indexPath.item]

    if let messageID = message.senderId {

        rootRef.child("users").child(messageID).observe(.value, with: { (snapshot) in

            if let profileURL = (snapshot.value as AnyObject!)!["profileURL"] as! String! {

                let profileNSURL: NSURL = NSURL(string: profileURL)!

                // download avatar image here somehow!?
                let manager: SDWebImageManager = SDWebImageManager.shared()
                manager.downloadImage(with: profileNSURL as URL!, options: [], progress: { (receivedSize: Int, actualSize: Int) in
                    print(receivedSize, actualSize)
                }, completed: { (image, error, cached, finished, url) in
                    avatarImage!.avatarImage = image
                })
            }
        })
    }

    return avatarImage
}

这和它打印出图像尺寸没有错误。然而图像并没有从占位符图像改变!...

Answer 1

万岁!我终于从文档中弄明白了……在所有地方。

您必须按如下方式初始设置现有头像...

所以在;

let message = messages[indexPath.item]

添加以下内容。

       if avatarImage?.avatarImage == nil {
       avatarImage?.avatarImage = SDImageCache.shared().imageFromDiskCache(forKey: message.senderId)
       }

然后检查 Avatars 是否存在，如果不存在，就去获取它们!但是将它们设置为您在现有头像中拥有的 key 。例如(message.senderID)

if image != nil {
manager.imageCache.store(image, forKey: message.senderId)

DispatchQueue.main.async
{                                
avatarImage!.avatarImage = image
avatarImage!.avatarHighlightedImage = image
}

砰!化身无处不在。希望这对某人有帮助!