Swift开发：自定义标签栏UITabBarController (Swift项目开始的第一步)

  class MainTabBarController: UITabBarController, MainTabBarDelegate{
    
    var tarbarConfigArr:[Dictionary<String,String>]! //标签栏配置数组，从Plist文件中读取
    var mainTabBarView: MainTabBarView! //自定义的底部TabbarView
    
    //MARK: - Life Cycle
    override init(nibName nibNameOrNil: String?, bundle nibBundleOrNil: Bundle?){
        //1.调用父类的初始化方法
        super.init(nibName: nil, bundle: nil)
        //2.读取Plist文件,初始化标签栏配置数组
        self.tarbarConfigArr = self.getConfigArrFromPlistFile()
        //3.创建视图控制器
        self.createControllers()
        //4.创建自定义TabBarView
        self.createMainTabBarView()
    }
    
    required init?(coder aDecoder: NSCoder){
        fatalError("init(coder:) has not been implemented")
    }
    
    override func viewDidLoad(){
        super.viewDidLoad()
    }
    
    override func viewWillAppear(_ animated: Bool){
        super.viewWillAppear(animated)
    }
    
    
    //MARK: - Private Methods
    //读取Tabbar配置文件
    private  func  getConfigArrFromPlistFile() ->([Dictionary<String,String>]?){
        let  filePath: String? = Bundle.main.path(forResource: "TabBarConfig", ofType: "plist")
        let plistData = NSDictionary(contentsOfFile: filePath ?? "")
        let configArr = plistData?.object(forKey: "Tabbars") as? [Dictionary<String,String>]
        return configArr;
    }

    //创建视图控制器
    private func createControllers(){
        var controllerNameArray = [String]() //控制器类名数组
        var controllerTitle = [String]()     //控制器Title数组
        for dictionary in self.tarbarConfigArr{
            controllerNameArray.append(dictionary["ClassName"]!);
            controllerTitle.append(dictionary["Title"]!)
            
        guard controllerNameArray.count > 0 else{
            print("error:控制器数组为空")
            return
        }
        //初始化导航控制器数组
        var nvcArray = [BaseNavigationViewController]()
        //在Swift中, 通过字符串创建一个类, 那么必须加上命名空间clsName
        let clsName = Bundle.main.infoDictionary!["CFBundleExecutable"] as! String
        for i in 0...controllerNameArray.count-1 {
            //动态获取的命名空间是不包含.的, 所以需要我们自己手动拼接
            let anyClass: AnyClass? = NSClassFromString(clsName + "." + controllerNameArray[i])
            //将AnyClass类型转换为BaseViewController类型，
            //因为Swift中通过一个Class来创建一个对象, 必须告诉系统这个Class的确切类型
            if let vcClassType = anyClass as? BaseViewController.Type {
                let viewcontroller = vcClassType.init()
                viewcontroller.title = controllerTitle[i]
                let nav = BaseNavigationViewController(rootViewController:viewcontroller)
                nvcArray.append(nav)
            }
        }
        //设置标签栏控制器数组
        self.viewControllers = nvcArray
        }
    }

    //创建自定义Tabbar
    private func createMainTabBarView(){
        //1.获取系统自带的标签栏视图的frame,并将其设置为隐藏
        let tabBarRect = self.tabBar.frame;
        self.tabBar.isHidden = true;
        //3.使用得到的frame，和plist数据创建自定义标签栏
        mainTabBarView = MainTabBarView(frame: tabBarRect,tabbarConfigArr:tarbarConfigArr!);
        mainTabBarView.delegate = self
        self.view .addSubview(mainTabBarView)
    }
    
    //MARK: - MainTabBarDelegate
    func didChooseItem(itemIndex: Int) {
        self.selectedIndex = itemIndex
    }
}

  //自定义标签栏代理协议
protocol MainTabBarDelegate {
    func didChooseItem(itemIndex:Int)
}

class MainTabBarView: UIView {
    var delegate:MainTabBarDelegate? //代理,点击item
    var itemArray:[MainTabBarItem] = [] //标签Item数组
   
    init(frame: CGRect,tabbarConfigArr:[Dictionary<String,String>]) {
        super.init(frame: frame)
        self.backgroundColor = UIColor.white
        let screenW = UIScreen.main.bounds.size.width
        let itemWidth = screenW / CGFloat(tabbarConfigArr.count)
        for i in 0..<tabbarConfigArr.count{
            let itemDic = tabbarConfigArr[i];
            let itemFrame = CGRect(x: itemWidth * CGFloat(i) , y: 0, width: itemWidth, height: frame.size.height)
            //创建Item视图
            let itemView = MainTabBarItem(frame: itemFrame, itemDic:itemDic, itemIndex: i)
            self.addSubview(itemView)
            self.itemArray.append(itemView)
            //添加事件点击处理
            itemView.tag = i
            itemView.addTarget(self, action:#selector(self.didItemClick(item:))  , for: UIControlEvents.touchUpInside)
            //默认点击第一个,即首页
            if i == 0 {
                self .didItemClick(item: itemView)
            }
        }
    }
   
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
   
    //点击单个标签视图，通过currentSelectState的属性观察器更新标签item的显示
    //并且通过代理方法切换标签控制器的当前视图控制器
    func didItemClick(item:MainTabBarItem){
        for i in 0..<itemArray.count{
            let tempItem = itemArray[i]
            if i == item.tag{
                tempItem.currentSelectState = true
            }else{
                tempItem.currentSelectState = false
            }
        }
        //执行代理方法
        self.delegate?.didChooseItem(itemIndex: item.tag)
    }
}

class MainTabBarItem: UIControl {
    var itemDic:Dictionary<String, String>
    let imgView: UIImageView
    let titleLabel: UILabel
   
    //属性观察器
    var currentSelectState = false {
        didSet{
            if currentSelectState {
                //被选中
                imgView.image = UIImage(named:itemDic["SelectedImg"]!)
                titleLabel.textColor = UIColor.red
            }else{
                //没被选中
                imgView.image = UIImage(named: itemDic["NormalImg"]!)
                titleLabel.textColor = UIColor.lightGray
            }
        }
    }
   
    init(frame:CGRect, itemDic:Dictionary<String, String>, itemIndex:Int) {
        self.itemDic = itemDic
       
        //布局使用的参数
        let defaulutLabelH:CGFloat = 20.0 //文字的高度
        var imgTop:CGFloat = 3
        var imgWidth:CGFloat = 25
        //中间的按钮的布局参数做特殊处理
        if itemIndex == 1{
            imgTop = -20
            imgWidth = 50
        }
        let imgLeft:CGFloat = (frame.size.width - imgWidth)/2
        let imgHeight:CGFloat  = frame.size.height - defaulutLabelH - imgTop
        //图片
        imgView = UIImageView(frame: CGRect(x: imgLeft, y: imgTop, width:imgWidth, height:imgHeight))
        imgView.image = UIImage(named: itemDic["NormalImg"]!)
        imgView.contentMode = UIViewContentMode.scaleAspectFit
        //title
        titleLabel = UILabel(frame:CGRect(x: 0, y: frame.height - defaulutLabelH, width: frame.size.width, height: defaulutLabelH))
        titleLabel.text = itemDic["Title"]!
        titleLabel.textAlignment = NSTextAlignment.center
        titleLabel.font = UIFont.systemFont(ofSize: 11)
        titleLabel.textColor = UIColor.lightGray
       
        super.init(frame: frame)
        self.addSubview(imgView)
        self.addSubview(titleLabel)
    }
   
    required init?(coder aDecoder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
}

    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
        //创建App窗口
        self.window = UIWindow(frame: UIScreen.main.bounds)
        self.window?.backgroundColor = UIColor.orange
        self.window?.makeKeyAndVisible()
        //设置Window的根视图控制器为自定义的标签栏
        self.window?.rootViewController = MainTabBarController();
        return true
    }