代码之家 › 专栏 › 技术社区 › Lukas Bimba

快速访问单元设置内的数据结构

swift ios

-1

Lukas Bimba · 技术社区 · 6 年前

我正在将一个firebase数据快照附加到一个nsobject,其中的项目是“客户”、“员工”和“业务”。设置如下:

var customerData = [CustomerData]()
var employeeData = [EmployeeData]()
var businessData = [BusinessData]()

func getCustomerData() {
    Database.database().reference().child("user_profiles").observe(.childAdded, with: { snapshot in
        self.customerData.append(CustomerData(snapshot: snapshot))
    })
}

func getEmployeeData() {
    Database.database().reference().child("employees").observe(.childAdded, with: { snapshot in
        self.employeeData.append(EmployeeData(snapshot: snapshot))
    })
}

func getBusinessData() {
    Database.database().reference().child("Businesses").observe(.childAdded, with: { snapshot in
        self.businessData.append(BusinessData(snapshot: snapshot))
    })
}

客户、员工和业务的数据结构如下

import UIKit
import Firebase

class CustomerData: NSObject {

var customerName: String?
var customerPicture: String?
var customerUID: String?

init(snapshot: DataSnapshot) {
    if let dictionary = snapshot.value as? [String: AnyObject] {
        customerName = dictionary["name"] as? String
        customerUID = dictionary["uid"] as? String
        customerPicture = dictionary["profPicString"] as? String
    }
}
}

我只想访问单元内的快照数据,以保持消息详细信息的最新,如配置文件图片和名称。下面是我的手机设置:

 override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: cellId, for: indexPath) as! ChatMessageCell

    cell.chatLogController = self

    let customer = customerData
    let employee = employeeData
    let business = businessData

    let message = messages[indexPath.row]

    cell.message = message
    cell.customer = customer
    cell.employee = employee
    cell.business = business

    setupChatMessageCell(cell,message,customer,employee,business)

    if let text = message.text {
        cell.textView.text = text
        cell.bubbleWidthAnchor?.constant = estimateSizeOfText(text).width + 32
        cell.textView.isHidden = false
    } else if message.imageUrl != nil {
        cell.bubbleWidthAnchor?.constant = 200
        cell.textView.isHidden = true
    }

    cell.playButton.isHidden = message.videoUrl == nil

    return cell
}

    private func setupChatMessageCell(_ cell: ChatMessageCell, _ message: GroupMessage, _ customer: CustomerData, _ employee: EmployeeData, _ business: BusinessData) {


    if message.fromId == customer.customerUID {
        //outgoing messages
        cell.bubbleView.backgroundColor = ChatMessageCell.blueColor
        cell.textView.textColor = .white
        cell.bubbleLeftAnchor?.isActive = false
        cell.bubbleRightAnchor?.isActive = true
        cell.profileImageView.isHidden = true
        cell.nameLabel.textColor = .gray
        cell.nameRightAnchor?.isActive = true
        cell.nameLeftAnchor?.isActive = false
        cell.nameLabel.text = message.name?.description
        //cell.nameLabel.text = message.customerName
    } else if message.fromId == employee.employeeUID {
        //incoming messagese
        let customerImage = employee.employeePicture
        cell.profileImageView.loadImageUsingCacheWithUrlString(customerImage!)
        cell.profileImageView.isHidden = false
        cell.bubbleView.backgroundColor = UIColor(red: 240, green: 240, blue: 240)
        cell.textView.textColor = .black
        cell.bubbleLeftAnchor?.isActive = true
        cell.bubbleRightAnchor?.isActive = false
        cell.profileImageView.isHidden = false
        cell.nameRightAnchor?.isActive = false
        cell.nameLeftAnchor?.isActive = true
        cell.nameLabel.textColor = .black
        cell.nameLabel.text = message.name?.description
    } else if message.fromId == business.businessUID {
        let customerImage = business.businessPicture
        cell.profileImageView.loadImageUsingCacheWithUrlString(customerImage!)
        cell.profileImageView.isHidden = false
        cell.bubbleView.backgroundColor = UIColor(red: 240, green: 240, blue: 240)
        cell.textView.textColor = .black
        cell.bubbleLeftAnchor?.isActive = true
        cell.bubbleRightAnchor?.isActive = false
        cell.profileImageView.isHidden = false
        cell.nameRightAnchor?.isActive = false
        cell.nameLeftAnchor?.isActive = true
        cell.nameLabel.textColor = .black
        cell.nameLabel.text = message.name?.description
    }

    if let imageUrl = message.imageUrl {
        cell.messageImageView.loadImageUsingCacheWithUrlString(imageUrl)
        cell.messageImageView.isHidden = false
        cell.bubbleView.backgroundColor = .clear
    } else {
        cell.messageImageView.isHidden = true
    }
}

问题是,我不认为以“[index.path]”访问它是正确的方式,这正是我处理“消息”的方式。如何在单元设置中访问这些数据结构,以便始终保持用户信息的最新?“无法将类型”[CustomerData]“的值赋给类型”CustomerData?“之类的错误。”那么,访问单元内这些数据结构的正确方法是什么呢?

1 回复 | 直到 6 年前

Robert Dresler Gustavo Vollbrecht 6 年前

问题是,我不认为以“[index.path]”访问它是正确的方式,这正是我处理“消息”的方式。

这不是真的。经过 row 或 item 性质 IndexPath 由于数据源数组中元素的索引是获取特定元素的正确方法。

但是,你在使用 UICollectionView ,所以您应该使用 项目 属性而不是 行 即使功能相同

UITababVIEW

let item = dataSourceArray[indexPath.row]

ui集合视图

let item = dataSourceArray[indexPath.item]

但是,对于正在设置某个单元格的其他方法,不应将该单元格作为参数传递。

相反,在集合视图的单元格子类中,创建用于设置单元格视图等的方法。

class ChatMessageCell: UICollectionViewCell {
    ...
    var message: Message!
    ...
    func setupCell() {
        ... // here you can work with cell's properites e.g. message, ...
    }
}

…然后打电话进来 cellForItemAt

在这个方法中,您应该更改与内容相关的内容。”“修饰”的内容,如更改视图颜色等。您可以将其设置在重写的内部 UICollectionViewCell 方法 prepareForReuse()

override func prepareForReuse() {
    super.prepareForReuse()
    ...
}