Question

我有一个private void ListDrawer() { regionList = new ArrayList<>(); try { JSONArray jsonMain= new JSONArray(JSONResult); for (int i = 0; i < jsonMain.length(); i++) { JSONObject jsonChild = jsonMain.getJSONObject(i); String id=jsonChild.optString("id"); String name=jsonChild.optString("name"); String description=jsonChild.optString("description"); String base_office=jsonChild.optString("base_office"); regionList.add(new RegionList(id, name, description,base_office)); } } catch (Exception ee) { MyRegionActivity.this.finish(); } ArrayAdapter adapter = new RegionListAdapter(MyRegionActivity.this, R.layout.activity_my_region, regionList); adapter.notifyDataSetChanged(); lv.setAdapter(adapter);，它是我应用中所有其他视图控制器的子类。

我有一些状态变量必须在所有视图控制器中保持一致，所以我打算编写代码，以便在BaseViewController中来回传递这些状态变量一次。为此，我提供了一个帮助函数BaseViewController用于向前传递并使用pushStatefulViewControllerWithIdentifier()进行向后传递。

StatePassBackDelegate

我这里有强大的参考周期吗？
我应该在这里使用单身模式吗？

Answer 1

我在代码中看不到保留周期。如果您担心某个对象在预期时没有被破坏，您可以记录其解除分配以进行检查：
```
deinit {
    print("deinit of \(self)")
}
```
同意，您需要为状态关怀引入一些模型级实体，而不是在控制器层上使用它。如果您不打算通过单元测试覆盖相关逻辑，单例就可以了。

<强> EDITED

您可以在app delegate中存储共享对象。

不确定我是否完全了解您的应用对象模型。我假设应该在所有应用程序中共享状态，因此最好将一些SystemStateMachine注入所有感兴趣的组件。希望它有所帮助：

    @UIApplicationMain
    class MyAppDelegate: UIResponder, UIApplicationDelegate {

        var controllersFactory: IViewControllersFactory! = nil

        func applicationDidFinishLaunching(application: UIApplication) {

            let storyboard = UIStoryboard(name:NSBundle.mainBundle().infoDictionary!["UIMainStoryboardFile"] as! String , bundle: NSBundle.mainBundle())
            controllersFactory = ViewControllersFactory(storyboard: storyboard, stateMachine: SystemStateMachine())
        }
    }

    struct SystemState : OptionSetType {
        let rawValue: Int

        static let None   = SystemState(rawValue: 0)
        static let Connected = SystemState(rawValue: 1 << 0)
        static let LoggedIn  = SystemState(rawValue: 1 << 1)

    }

    protocol ISystemStateMachine {

        var currentState: SystemState { get set }
    }

    class SystemStateMachine: ISystemStateMachine {

        var currentState: SystemState = .None
    }

    protocol IViewControllersFactory {

        func instantiateViewController(identifier: String) -> BaseViewController?
    }

    class ViewControllersFactory: IViewControllersFactory {

        let _storyboard: UIStoryboard
        let _stateMachine: ISystemStateMachine

        init(storyboard: UIStoryboard, stateMachine: ISystemStateMachine) {
            _storyboard = storyboard
            _stateMachine = stateMachine
        }

        func instantiateViewController(identifier: String) -> BaseViewController? {
            if let vc = _storyboard.instantiateViewControllerWithIdentifier(identifier) as? BaseViewController {
                vc.stateMachine = _stateMachine
                return vc
            }
            return nil
        }
    }

    class BaseViewController: UIViewController {

        var stateMachine: ISystemStateMachine!

        // MARK: Lifecycle
        func somethingWorthHappen() {
            //switch state
            stateMachine.currentState.insert(.Connected)
        }
        func somethingWorth2Happen() {
            //switch state
            stateMachine.currentState.insert(.LoggedIn)

            guard let appDelegate = UIApplication.sharedApplication().delegate as? MyAppDelegate else {
                //log an error
                return
            }
            if let vc = appDelegate.controllersFactory.instantiateViewController("myViewController") {
                navigationController!.pushViewController(vc, animated: true)
            }
        }
    }

我这里有强大的参考周期吗？

1 个答案: