其实抓下京东app的首页，或者别的大型项目的首页啥的，一般会抓到多个页面相关的接口，例如轮播图的、数据列表、等等。
很多app会把所有接口请求完才展示数据，如果其中有一个错误就整个页面展示错误页面，我感觉这是对好的接口的一种浪费，所以我感觉应该做到 请求到一个就展示一个接口的数据；比如说轮播图请求成功就展示轮播图的 没请求成功的在相关的UI模块展示没成功的错误页面。
废话不说了，上代码；举例 加载框吧‘

WechatIMG8.png

先看使用

    func loadAData() {
        aView.showLoadingView()
        RequestManager.request(path: "xxx/project-list", parameters: nil) { result in
            aView.view.hiddenLoadingView()
            switch result {
            case .success(let data) :
               self.updateUI(data: data)             
                let state:EmptyViewState = list.count == 0 ? .emptyData : .none
                aView.showEmptyView(state: state) {
                    self.loadAData()
                }
                break
            case .failure(let error):
                aView.showEmptyView(state: error.toEmptyState()) {
                    self.loadAData()
                }
                aView.showToast(message: error.msg)
                break
            }
        }
    }

实现

//
//  TKHUD.swift
//  模块开发
//
//  Created by 天空吸引我 on 2020/6/11.
//  Copyright © 2020 libtinker. All rights reserved.
//

import UIKit

class TKHUD:UIView {

   lazy var messageLabel:UILabel = {
        let label = UILabel()
        label.font = UIFont.systemFont(ofSize: 14.0)
        label.textColor = UIColor.white
        label.layer.masksToBounds = true
        label.numberOfLines = 0
        label.textAlignment = .center
       return label
    }()
    
    lazy var contentView:UIView = {
        let view = UIView()
        view.frame = CGRect.init(x: 0, y: 0, width: 100, height: 100)
        view.backgroundColor = UIColor.init(red: 58/255.0, green: 59/255.0, blue: 73/255.0, alpha: 1.0).withAlphaComponent(0.5)
        view.layer.cornerRadius = 4.0
        self.addSubview(view)
        return view
    }()
        
    lazy var activityIndicatorView:UIActivityIndicatorView = {
        let activityIndicatorView = UIActivityIndicatorView()
        activityIndicatorView.frame = CGRect.init(x: 10, y: 10, width: 80, height: 80)
        activityIndicatorView.color = UIColor.white
        if #available(iOS 13.0, *) {
            activityIndicatorView.style = .large
        } else {
            activityIndicatorView.style = .whiteLarge
        }
        self.addSubview(activityIndicatorView)
        return activityIndicatorView
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        
        self.isUserInteractionEnabled = false
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    public func addLoadingView() {
        self.contentView.addSubview(self.activityIndicatorView)
        self.contentView.center = self.center
        self.activityIndicatorView.startAnimating()
    }

    public func addToastView(message:String) {
        self.contentView.backgroundColor = UIColor.black.withAlphaComponent(0.5)
        let boundingRect = message.boundingRect(with: CGSize(width: self.bounds.size.width-90, height: CGFloat.greatestFiniteMagnitude), options: .usesLineFragmentOrigin, attributes:[NSAttributedString.Key.font:UIFont.systemFont(ofSize: 14)], context: nil)
        self.contentView.frame = CGRect.init(x: 0, y: 0, width: self.bounds.size.width-60, height: boundingRect.height+20)
        self.contentView.center = self.center;
        
        self.messageLabel.text = message
        self.contentView.addSubview(self.messageLabel)
        self.messageLabel.frame = CGRect(x: (self.contentView.bounds.size.width-boundingRect.width)/2, y: (self.contentView.bounds.size.height-boundingRect.height)/2, width: boundingRect.width, height:boundingRect.height)
    }
}

extension UIView {
    public func showLoadingView(){
        let loadingView = TKHUD(frame: self.bounds)
        loadingView.addLoadingView()
        self.addSubview(loadingView);
    }
    
    public func hiddenLoadingView(){
        for  subView in self.subviews {
            if subView.classForCoder == TKHUD.classForCoder() {
                subView.removeFromSuperview()
            }
        }
    }
    
    public func showToast(message:String,afterDelay:TimeInterval = 2.5) {
        let toastView = TKHUD(frame: self.bounds)
        toastView.addToastView(message: message)
        self.addSubview(toastView)
        if afterDelay>0 {
            DispatchQueue.main.asyncAfter(deadline: .now() + afterDelay) {
                toastView.removeFromSuperview()
            }
        }
    }
}