swift 展示无网络view

1. 用xib自定义view，类型：NetworkStateView

2. 因为多个界面要使用该view，就统一在UIViewController的扩展中提供显示、移出2个方法

//
// MARK: - 网络监测
//
fileprivate var kNetworkName: String = "kNetworkName"
extension UIViewController {
    
    fileprivate var vNetwork: NetworkStateView? {
        set {
            objc_setAssociatedObject(self, &kNetworkName, newValue, objc_AssociationPolicy.OBJC_ASSOCIATION_RETAIN_NONATOMIC)
        }
        get {
            return objc_getAssociatedObject(self, &kNetworkName) as? NetworkStateView
        }
    }
    
    ///无网络，vc遵守NetworkStateViewProtocol协议
    func extShowNetworkStateView(vc: UIViewController & NetworkStateViewProtocol) {
        
        vNetwork = NetworkStateView.loadUseXibName()
        vNetwork?.frame = self.view.bounds
        vNetwork?.delegate = vc
        view.addSubview(vNetwork!)
    }

    ///移出
    func extRemoveNetworkStateView() {
        vNetwork?.delegate = nil
        
        UIView.animate(withDuration: kAnimateTime, animations: {
            self.vNetwork?.alpha = 0.1
        }) { (done) in
            self.vNetwork?.removeFromSuperview()
        }
    }
}

////
//// MARK: - NetworkStateViewProtocol
////
//extension UIViewController: NetworkStateViewProtocol {
//    func networkStateViewReload(_ view: NetworkStateView) {
//    }
//}

3. ViewController根据网络状态显示移出无网络view

• 显示

if ReachableManager.shared.stateUseless {
    extShowNetworkStateView(vc: self)
}

• 移出

extRemoveNetworkStateView()

• 遵守NetworkStateViewProtocol协议

//
// MARK: - NetworkStateViewProtocol
//
extension IdentifyCategoryVC: NetworkStateViewProtocol {
    func networkStateViewReload(_ view: NetworkStateView) {
        loadData()
    }
}