spaghetti code loading view was spread in almost view controller.

LoginVC.swift

import SJProgressHUD
//import anything
//we also put SJProgressHUD in almost ViewController which need to render loading view.
class LoginVC: UIViewController {
  func viewDidLoad(){
    //other code here...
  }
  func buttonTapped(){
    //other logic here...
    SJProgressHUD.show(...)
  }
  func functionThatNeedToShowPopupError(){
    //other code here... blahblah blah
    SJProgressHUD.showError(...)
  }
  func otherFunction(){
    //other code here... @!(njdn910>!
    SJProgressHUD.hide()
    //and code again here...wtf!
  }
}