前言

过去的2016年是一个直播年，各大平台都相继接入了直播频道，电商，社交…更是火了一批做视频的，譬如喵播，映客，都斗鱼等直播平台。全民直播，一下子掀起了直播的技术潮，今天要聊聊如何实现一个ios的直播app。首先来看最终的效果：

最近也是因为入门swift不久，在网上找了一个项目就开始模仿，本项目用到的第三方库： Alamofire Kingfisher

Swift3.0的蝶变

swift3.0相对于2.x，渐渐的脱离了oc和c的风格，不管是从命名规范还是新能上都有了较大的提升，笔者认为应该是未来一个相对稳定的版本，而不是1.0和2.0时代的实验版本。相对于2.x，我们来看3.0或以后的3.x主要有哪些特性： 稳定二进制接口（ABI) API大家都知道是应用程序接口 API只是提供函数签名，而ABI是系统和语言层面的如果ABI稳定意味着以后Swift版本更新升级我们不需要再修改老版本 Swift 语言编译的库了。 弹性/韧性解决易碎二进制接口问题 Fragile binary interface problem是面向对象编程语言的通病如果在程序中引入了外部库我们的的程序中使用并继承了该外部库中的类如果外部库有改动我们必须重新编译所有该类的继承树而这类问题被称为脆弱的基类 (Fragile base class) 可移植性 这个对于高级语言是很重要的特性，这意味着Swift可被移植到其他平台上。 全面支持泛型特性 Swift 2.2已经很好的支持泛型但是还不够完善，Swift 3.0开始将全面支持泛型的所有特性。 新的API设计规范 Swift3.0 发布了新的语言设计规范其中在Swift3.0中标准库和核心库将会遵循这个设计规范。规范地址 从函数参数中删除var关键字

func doSomethingWithVar(var i: Int) {
     i = 2 // This will NOT have an effect on the caller's Int that was passed, but i can be modified locally
  }

func doSomethingWithInout(inout i: Int) {
       i = 2 // This will have an effect on the caller's Int that was passed.
}  

doSomethingWithVar(x)  
 print(x) // 1

doSomethingWithInout(&x)
 print(x) // 2

删除var是因为var与inout会产生歧义和混乱。 为autoreleasepool添加错误处理 旧版autoreleasepool处理错误方式：

func doWork() throws -> Result {
   var result: Result? = nil
   var error: ErrorProtocol? = nil
   autoreleasepool { 
          do {
            ... actual computation which hopefully assigns to result but might not ...
         } catch let e {
                       error = e
          }
     } 

    guard let result = result else { 
              throw error! 
      } 
          return result!
  }

Swift3.0 autoreleasepool 处理错误方式：

public func autoreleasepool<Result>(@noescape body: () throws -> Result) rethrows -> Result

  func doWork() throws -> Result {

     return try autoreleasepool
         { 
                 ... actual computation which either returns or throws       ...         
         }
}

允许直接引用（Default, Private, Repeat）关键字成员 在Swift3.0之前我们引用default和repeat成员时需要这样写：

let cell = UITableViewCell(style: .`default`, reuseIdentifier: nil)
particleSystem.imageSequenceAnimationMode = SCNParticleImageSequenceAnimationMode.`repeat`

Swift3.0时允许我们直接访问default repeat 关键字成员：

let cell = UITableViewCell(style: .default, reuseIdentifier: nil)
particleSystem.imageSequenceAnimationMode = SCNParticleImageSequenceAnimationMode.repeat

将声明式@noescape和@autoclosure 改为类型属性

func f(@noescape fn : () -> ()) {} // declaration  attribute 

//新的语法
func f(fn : @noescape () -> ()) {} // type attribute.
func f2(a : @autoclosure () -> ()) {} // type attribute.

重命名 Debug 标示符 Debug 标示符重命名后将会与#available #selector 关键字统一风格。

__FILE__ ->  #file
__LINE__ -> #line
__COLUMN__ -> #column
__FUNCTION__ -> #function
__DSO_HANDLE__ -> #dsohandle

斗鱼部分代码分析

本app采用的是mvvm的开发架构，做到业务，数据，页面的真正分离，我们来看几个核心的类： base

import UIKit  

private let kItemMargin : CGFloat = 10  
private let kHeaderViewH : CGFloat = 50  
private let NormalCellID = "NormalCellID"  
private let HeaderViewID = "HeaderViewID"  
let kNormalItemW = (kScreenW - 33 * kItemMargin) / 2  
let kNormalItemH = kNormalItemW * 3 / 4  
let kPrettyItemH = kNormalItemW * 5 / 4  
let PrettyCellID = "PrettyCellID"  

class BaseAnchorVC: BaseVC {  

    //!表示用到的时候保证有值  
    var baseVM : BaseVM!  

    lazy var collectionView : UICollectionView = {[unowned self] in  
        let layout = UICollectionViewFlowLayout()  
        layout.itemSize = CGSize(width: kNormalItemW, height: kNormalItemH)  
        layout.minimumLineSpacing = 0  
        layout.minimumInteritemSpacing = kItemMargin  
        layout.headerReferenceSize = CGSize(width: kScreenW, height: kHeaderViewH)  
        layout.sectionInset = UIEdgeInsets(top: 0, left: kItemMargin, bottom: 0, right: kItemMargin)  

        let collectionView = UICollectionView(frame: self.view.bounds, collectionViewLayout: layout)  
        collectionView.backgroundColor = UIColor.white  
        collectionView.dataSource = self  
        collectionView.delegate = self  
        collectionView.autoresizingMask = [.flexibleHeight, .flexibleWidth]  

        collectionView.register(UINib(nibName: "CollectionNormalCell", bundle: nil), forCellWithReuseIdentifier: NormalCellID)  
        collectionView.register(UINib(nibName: "CollectionPrettyCell", bundle: nil), forCellWithReuseIdentifier: PrettyCellID)  
        collectionView.register(UINib(nibName: "CollectionHeaderView", bundle: nil), forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: HeaderViewID)  

        return collectionView  
        }()  

    override func viewDidLoad() {  
        super.viewDidLoad()  
        setupUI()  
        loadData()  
    }  

}  

extension BaseAnchorVC {  
    override func setupUI() {  
        contentView = collectionView  
        view.addSubview(collectionView)  
        super.setupUI()  
    }  
}  

extension BaseAnchorVC {  
    func loadData() {  
    }  
}  

extension BaseAnchorVC : UICollectionViewDataSource {  
    func numberOfSections(in collectionView: UICollectionView) -> Int {  
        return baseVM.anchorGroups.count  
    }  

    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {  
        return baseVM.anchorGroups[section].anchors.count  
    }  

    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {  
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: NormalCellID, for: indexPath) as! CollectionNormalCell  
        cell.anchor = baseVM.anchorGroups[indexPath.section].anchors[indexPath.item]  
        return cell  
    }  

    func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {  
        let headerView = collectionView.dequeueReusableSupplementaryView(ofKind: kind, withReuseIdentifier: HeaderViewID, for: indexPath) as! CollectionHeaderView  
        headerView.group = baseVM.anchorGroups[indexPath.section]  
        return headerView  
    }  

}  

extension BaseAnchorVC : UICollectionViewDelegate {  
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {  
        let anchor = baseVM.anchorGroups[indexPath.section].anchors[indexPath.item]  
        anchor.isVertical == 0 ? pushNormalRoomVc(anchor) : presentShowRoomVc(anchor)  
    }  

    private func presentShowRoomVc(_ anchor : AnchorModel) {  
        let showVc = ShowRoomVC()  
        showVc.anchor = anchor  
        present(showVc, animated: true, completion: nil)  
    }  

    private func pushNormalRoomVc(_ anchor : AnchorModel) {  
        let normalVc = NormalRoomVC()  
        normalVc.anchor = anchor  
        navigationController?.pushViewController(normalVc, animated: true)  
    }  
}

import UIKit  

class GameVC: BaseAnchorVC {  
    fileprivate lazy var gameVM : GameVM = GameVM()  
    fileprivate lazy var menuView : MenuView = {  
        let menuView = MenuView.menuView()  
        menuView.frame = CGRect(x: 0, y: -kMenuViewH, width: kScreenW, height: kMenuViewH)//设置collectionView的-y,放置menuView  
        return menuView  
    }()  

}  

extension GameVC {  
    override func setupUI() {  
        super.setupUI()  
        collectionView.addSubview(menuView)  
        collectionView.contentInset = UIEdgeInsets(top: kMenuViewH, left: 0, bottom: 0, right: 0)//设置内边距  
    }  
}  

extension GameVC{  
    override func loadData() {  
        baseVM = self.gameVM  
        gameVM.requestData {  
            self.collectionView.reloadData()  
            var gameGroups = Array(self.gameVM.anchorGroups[1...15])//0...15 & gameGroups.removeFirst()  
            let moreGroup = AnchorGroup()  
            moreGroup.tag_name = "更多分类"  
            gameGroups.append(moreGroup)  
            self.menuView.groups = gameGroups  
            self.loadDataFinished()  
        }  
    }  
}

请求类：

import UIKit  
import Alamofire  

enum MethodType {  
    case get  
    case post  
}  

class HttpTools {  
    class func requestData(_ type : MethodType, URLString : String, parameters : [String : Any]? = nil, finishedCallback :  @escaping (_ result : Any) -> ()) {  
        let method = type == .get ? HTTPMethod.get : HTTPMethod.post  
        Alamofire.request(URLString, method: method, parameters: parameters).responseJSON { (response) in  
            guard let result = response.result.value else {  
                print(response.result.error)  
                return  
            }  
            finishedCallback(result)  
        }  
    }  
}

附：swift斗鱼app界面 oc代码原文

高仿ios斗鱼界面

前言

Swift3.0的蝶变

斗鱼部分代码分析