UI: docker

UI: 容器视图
Container，
非常的有用。

对的

//tabbar背景视图
    private var bgView: UIView?

func clickBtn(curBtn: UIButton) {
        
        //1.取消之前选中按钮的状态
        let lastBtnView = bgView!.viewWithTag(300+selectedIndex)
        if let tmpBtn = lastBtnView {
            //上次选中的按钮
            let lastBtn = tmpBtn as! UIButton
            let lastView = tmpBtn.viewWithTag(400)
            if let tmpLabel = lastView {
                //上次选中的标签
                let lastLabel = tmpLabel as! UILabel
                lastBtn.selected = false
                lastLabel.textColor = UIColor.grayColor()
            }
        }
        
        //2.设置当前选中按钮的状态
        let curLabelView = curBtn.viewWithTag(400)
        if let tmpLabel = curLabelView {
            let curLabel = tmpLabel as! UILabel
            
            curBtn.selected = true
            curLabel.textColor = UIColor.orangeColor()
        }
        
        //3.选中视图控制器
        selectedIndex = curBtn.tag - 300
        
    }

崩的

func clickBtn(curBtn: UIButton) {
        
        //1.取消之前选中按钮的状态
        let lastBtnView = self.view.viewWithTag(300+selectedIndex)          //看这里
        if let tmpBtn = lastBtnView {