我正在制作社交媒体应用。
用户 - 显示名称 - 用户名 - profileImg - 密码 - 电子邮件
评论 - 用户名 - 评论 - 到
朋友 - 追随者 - 关注
主题标签 - 井号 - 至 - 通过 - 评论
喜欢 - 至 - 通过
帖子 - postImg - 用户名 - 标题 - uuid
我的问题是当用户发布带有标题文字的图像时 我想要检索用户名，profileImg，标题，评论，评论，postImg，喜欢计数
我的方法是重新设计帖子db
帖子 - postImg - 用户名 - 标题 - uuid - 评论 - 评论 - profileImg - 喜欢的次数
但我认为这是糟糕的db设计。
func loadPosts() {
//STEP 1. Find posts related to people who we are following
let followQuery = PFQuery(className: “friends")
followQuery.whereKey(“following", equalTo: PFUser.current()!.username!)
followQuery.findObjectsInBackground (block: { (objects:[PFObject]?, error:Error?) -> Void in
if error == nil {
//clean up
self.followArray.removeAll(keepingCapacity: false)
//Appending where people following..
//find related objects
for object in objects! {
self.followArray.append(object.object(forKey: “following") as! String)
}
//append current user to see own posts in feed
self.followArray.append(PFUser.current()!.username!)
//STEP 2. Find posts made by people appended to followArray
let query = PFQuery(className: "posts")
query.whereKey("username", containedIn: self.followArray)
query.limit = self.page
query.addDescendingOrder("createdAt")
query.findObjectsInBackground(block: { (objects:[PFObject]?, error:Error?) -> Void in
if error == nil {
//clean up
self.usernameArray.removeAll(keepingCapacity: false)
// self.profileArray.removeAll(keepCapacity: false)
self.dateArray.removeAll(keepingCapacity: false)
self.postArray.removeAll(keepingCapacity: false)
self.descriptionArray.removeAll(keepingCapacity: false)
self.uuidArray.removeAll(keepingCapacity: false)
self.commentsArray.removeAll(keepingCapacity: false)
self.commentsByArray.removeAll(keepingCapacity: false)
//find related objects
for object in objects! {
self.usernameArray.append(object.object(forKey: "username") as! String)
// self.profileArray.append(object.objectForKey("profileImg") as! PFFile)
self.dateArray.append(object.createdAt)
self.postArray.append(object.object(forKey: "postImg") as! PFFile)
self.descriptionArray.append(object.object(forKey: "title") as! String)
self.uuidArray.append(object.object(forKey: "uuid") as! String)
//set Comments
let comment = object.object(forKey: "comment") as! String
let by = object.object(forKey: "commentby") as! String
let commentString = " " + comment
self.commentsByArray.append(by)
self.commentsArray.append(commentString)
}
//reload tableView & end spinning of refresher
self.tableView.reloadData()
self.refresher.endRefreshing()
} else {
print(error!.localizedDescription)
}
})
} else {
print(error!.localizedDescription)
}
})
}
定义的单元格
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
//define cell
let cell = tableView.dequeueReusableCell(withIdentifier: "ShopDetailCell", for: indexPath) as! ShopDetailCell
cell.userNameLabel.text = usernameArray[(indexPath as NSIndexPath).row - 1]
cell.userNameLabel.sizeToFit()
cell.uuidLabel.text = uuidArray[(indexPath as NSIndexPath).row - 1]
cell.descriptionLabel.text = descriptionArray[indexPath.row - 1]
cell.descriptionLabel.sizeToFit()
cell.commentLabel.sizeToFit()
//Load ProfileImage
let profileImgQuery = PFQuery(className: "_User")
profileImgQuery.whereKey("username", equalTo: usernameArray[(indexPath as NSIndexPath).row - 1])
profileImgQuery.findObjectsInBackground(block: {(objects:[PFObject]?, error:Error?) -> Void in
if error == nil {
//shown wrong user
if objects!.isEmpty {
print("Wrong User")
}
//find related to user information
for object in objects! {
//Set Image
let profilePictureObject = object.object(forKey: "profileImg") as? PFFile
profilePictureObject?.getDataInBackground { (imageData:Data?, error:Error?) -> Void in
if(imageData != nil)
{
let profileURL : URL = URL(string: profilePictureObject!.url!)!
cell.userImg.sd_setImage(with: profileURL, placeholderImage: UIImage(named: "holderImg"))
}
}
}
} else {
print(error?.localizedDescription)
}
})
//Clip to circle
cell.userImg.layoutIfNeeded()
cell.userImg.layer.cornerRadius = cell.userImg.frame.size.width/2
cell.userImg.clipsToBounds = true
// place post picture using the sdwebimage
let postURL : URL = URL(string: postArray[(indexPath as NSIndexPath).row - 1].url!)!
cell.postImg.sd_setImage(with: postURL, placeholderImage: UIImage(named: "holderImg"))
//Calculate post date
let from = dateArray[(indexPath as NSIndexPath).row - 1]
let now = Date()
let components : NSCalendar.Unit = [.second, .minute, .hour, .day, .weekOfMonth]
let difference = (Calendar.current as NSCalendar).components(components, from: from!, to: now, options: [])
// logic what to show : Seconds, minutes, hours, days, or weeks
if difference.second! <= 0 {
cell.dateLabel.text = "NOW"
}
if difference.second! > 0 && difference.minute! == 0 {
cell.dateLabel.text = "\(difference.second!) SEC AGO"
}
if difference.minute! > 0 && difference.hour! == 0 {
cell.dateLabel.text = "\(difference.minute!) MIN AGO"
}
if difference.hour! > 0 && difference.day! == 0 {
cell.dateLabel.text = "\(difference.hour!) HR AGO"
}
if difference.day! > 0 && difference.weekOfMonth! == 0 {
cell.dateLabel.text = "\(difference.day!) DAY AGO"
}
if difference.weekOfMonth! > 0 {
cell.dateLabel.text = "\(difference.weekOfMonth!) WEEK AGO"
}
cell.dateLabel.sizeToFit()
//Set Text Label
if cell.descriptionLabel.text!.isEmpty == true || cell.descriptionLabel.text == " "{
if cell.commentLabel.text!.isEmpty == true || cell.commentLabel.text == " "{
cell.dateTop.constant = 7
}else {
cell.dateTop.constant = cell.commentTop.constant + cell.commentLabel.frame.height + 8
}
}else {
if cell.commentLabel.text!.isEmpty == true || cell.commentLabel.text == " "{
cell.dateTop.constant = cell.descriptionTop.constant + cell.descriptionLabel.frame.height + 8
}else {
cell.commentTop.constant = cell.descriptionTop.constant + cell.descriptionLabel.frame.height + 8
cell.dateTop.constant = cell.commentTop.constant + cell.commentLabel.frame.height + 8
}
}
// manipulate like button depending on did user like it or not
let didLike = PFQuery(className: "likes")
didLike.whereKey("by", equalTo: PFUser.current()!.username!)
didLike.whereKey("to", equalTo: cell.uuidLabel.text!)
didLike.countObjectsInBackground(block: {(count:Int32, error:Error?) -> Void in
//if no any likes are found, else found likes
if count==0 {
cell.likeBtn.setTitle("unlike", for: UIControlState())
cell.likeBtn.setImage(UIImage(named:"heartBtn"), for: UIControlState())
}else{
cell.likeBtn.setTitle("like", for: UIControlState())
cell.likeBtn.setImage(UIImage(named: "heartTapBtn"), for: UIControlState())
}
})
//count total likes of shown post
let countLikes = PFQuery(className: "likes")
countLikes.whereKey("to", equalTo: cell.uuidLabel.text!)
countLikes.countObjectsInBackground(block: {(count:Int32, error:Error?) -> Void in
cell.likesLabel.text="\(count) likes"
})
cell.userNameLabel.layer.setValue(indexPath, forKey: "index")
cell.commentBtn.layer.setValue(indexPath, forKey: "index")
cell.moreBtn.layer.setValue(indexPath, forKey: "index")
return cell
}
你们有人可以建议我吗？
我已阅读本教程“https://parse.com/tutorials/anypic”，但我无法确定哪种数据模型对我更好
我希望使用连接或指针方法。
答案 0 :(得分：1)
只要用户发帖，您就可以将currentUser保存为Posts类中的指针。
注意：我将在Objective-C中进行演示，但您很容易将其转换为Swift。但是如果您在阅读objc代码时遇到问题，我将编辑我对Swift版本的回答。
func post { //make a post
var post = PFObject(className:"Posts")
post["user"] = PFUser.current()//save the current user as a pointer pointing to the User class. You can add a column of type pointer in your parse dashboard inside your Posts class.
//set up other attributes here...
post.saveInBackground()
}
然后，当我们进行查询时，我们可以使用includeKey来包含用户指针。
let query = PFQuery(className: "posts")
query.whereKey("username", containedIn: self.followArray)
query.includeKey("user")// THIS IS IMPORTANT
query.limit = self.page
query.addDescendingOrder("createdAt")
query.findObjectsInBackground(block: { (objects:[PFObject]?, error:Error?) -> Void in
if !error {
//we can access the user pointer by doing:
for object in objects {
var user = object["user"]
var username = user.username
var profileImage = user["profileImg"] //a PFFile
//...
}
}
此外，您始终可以使用PFQueryTableViewController为您加载对象，因此您无需手动存储查询结果。