swift-stroybord和xib关联文件

单独的view进行关联，如下

 class func sharedInstance() -> DeviceAlertView {        let nibView = Bundle.main.loadNibNamed("DeviceAlertView", owner: self, options: nil)!.first as! DeviceAlertView        nibView.backgroundColor = UIColor.black.withAlphaComponent(0.4)        nibView.frame = UIScreen.main.bounds        return nibView    }

stroybord上用了view，又用另外的的xib进行关联，如下

override init(frame: CGRect) {        super.init(frame: frame)        initViewFromNib()    }    required init?(coder aDecoder: NSCoder) {        super.init(coder: aDecoder)        initViewFromNib()    }    private func initViewFromNib() {        let nibView = Bundle.main.loadNibNamed("SearchEmptyView", owner: self, options: nil)?[0] as! UIView        self.searchEmptyView = nibView        self.searchEmptyView.frame = bounds        self.addSubview(searchEmptyView)    }