work on #1065

lib/android/app/src/main/java/com/reactnativenavigation/NavigationActivity.java

 import android.os.Bundle;
 import android.support.annotation.Nullable;
 import android.support.v7.app.AppCompatActivity;
-import android.widget.FrameLayout;
 
 import com.facebook.react.modules.core.DefaultHardwareBackBtnHandler;
-import com.reactnativenavigation.viewcontrollers.ViewController;
+import com.reactnativenavigation.viewcontrollers.Navigator;
 
 public class NavigationActivity extends AppCompatActivity implements DefaultHardwareBackBtnHandler {
-	private ViewController viewController;
+	private Navigator navigator;
 
 	@Override
 	protected void onCreate(@Nullable Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
-		setContentView(new FrameLayout(this));
-		app().getInitializer().onActivityCreated(this);
+		navigator = new Navigator(this);
+		navigator.onActivityCreated();
 	}
 
 	@Override
 	protected void onResume() {
 		super.onResume();
-		app().getInitializer().onActivityResumed(this);
+		navigator.onActivityResumed();
 	}
 
 	@Override
 	protected void onPause() {
 		super.onPause();
-		app().getInitializer().onActivityPaused(this);
+		navigator.onActivityPaused();
 	}
 
 	@Override
 	protected void onDestroy() {
 		super.onDestroy();
-		app().getInitializer().onActivityDestroyed(this);
-	}
-
-
-	public void setViewController(ViewController viewController) {
-		this.viewController = viewController;
-		setContentView(viewController.getView());
+		navigator.onActivityDestroyed();
 	}
 
 	@Override
 
 	@Override
 	public void onBackPressed() {
-		if (!viewController.handleBack()) {
+		if (!navigator.handleBack()) {
 			super.onBackPressed();
 		}
 	}
 
-	private NavigationApplication app() {
-		return ((NavigationApplication) getApplication());
+	public Navigator getNavigator() {
+		return navigator;
 	}
 }

lib/android/app/src/main/java/com/reactnativenavigation/NavigationApplication.java

 package com.reactnativenavigation;
 
+import android.app.Activity;
 import android.app.Application;
+import android.os.Bundle;
 
 import com.facebook.react.ReactApplication;
 import com.facebook.react.ReactNativeHost;
 import com.reactnativenavigation.react.NavigationReactInitializer;
 import com.reactnativenavigation.react.NavigationReactNativeHost;
 
-public abstract class NavigationApplication extends Application implements ReactApplication {
+public abstract class NavigationApplication extends Application implements ReactApplication, Application.ActivityLifecycleCallbacks {
 
 	private Store store;
 	private NavigationReactNativeHost reactNativeHost;
 		store = new Store();
 		reactNativeHost = new NavigationReactNativeHost(this, isDebug(), store);
 		initializer = new NavigationReactInitializer(reactNativeHost.getReactInstanceManager(), isDebug());
+		registerActivityLifecycleCallbacks(this);
 	}
 
 	@Override
 
 	public abstract boolean isDebug();
 
-	NavigationReactInitializer getInitializer() {
-		return initializer;
+	@Override
+	public void onActivityCreated(final Activity activity, final Bundle savedInstanceState) {
+		if (activity instanceof NavigationActivity) {
+			initializer.onActivityCreated((NavigationActivity) activity);
+		}
+	}
+
+	@Override
+	public void onActivityStarted(final Activity activity) {
+	}
+
+	@Override
+	public void onActivityResumed(final Activity activity) {
+		if (activity instanceof NavigationActivity) {
+			initializer.onActivityResumed((NavigationActivity) activity);
+		}
+	}
+
+	@Override
+	public void onActivityPaused(final Activity activity) {
+		if (activity instanceof NavigationActivity) {
+			initializer.onActivityPaused((NavigationActivity) activity);
+		}
+	}
+
+	@Override
+	public void onActivityStopped(final Activity activity) {
+	}
+
+	@Override
+	public void onActivitySaveInstanceState(final Activity activity, final Bundle outState) {
+	}
+
+	@Override
+	public void onActivityDestroyed(final Activity activity) {
+		if (activity instanceof NavigationActivity) {
+			initializer.onActivityDestroyed((NavigationActivity) activity);
+		}
 	}
 }

lib/android/app/src/main/java/com/reactnativenavigation/layout/impl/ReactRootViewController.java

 	private final String id;
 	private final String name;
 	private final ReactInstanceManager reactInstanceManager;
+	private boolean attachedToReactInstance = false;
 
 	public ReactRootViewController(final Activity activity, final String id, final String name, final ReactInstanceManager reactInstanceManager) {
 		super(activity);
 //
 //	private void onStop() {
 //		new NavigationEvent(reactInstanceManager.getCurrentReactContext()).containerStop(id);
+//	}
+
+//	@Override
+//	public void onStart() {
+//		super.onStart();
+//		if (attachedToReactInstance) {
+//			new NavigationEvent(reactInstanceManager.getCurrentReactContext()).containerStart(id);
+//		} else {
+//			throw new RuntimeException("Not yet attached to react");
+//		}
 //	}
 
 	@Override
 			@Override
 			public void onAttachedToReactInstance(final ReactRootView reactRootView) {
 				reactRootView.setEventListener(null);
-				onStart();
+				attachedToReactInstance = true;
 			}
 		});
 		return reactRootView;

lib/android/app/src/main/java/com/reactnativenavigation/react/NavigationModule.java

 import com.reactnativenavigation.parse.JSONParser;
 import com.reactnativenavigation.parse.LayoutNodeParser;
 import com.reactnativenavigation.utils.UiThread;
+import com.reactnativenavigation.viewcontrollers.Navigator;
 import com.reactnativenavigation.viewcontrollers.ViewController;
 
 public class NavigationModule extends ReactContextBaseJavaModule {
 			public void run() {
 				final LayoutNode layoutTree = LayoutNodeParser.parse(JSONParser.parse(rawLayoutTree));
 				final ViewController viewController = newLayoutFactory().createAndSaveToStore(layoutTree);
-				activity().setViewController(viewController);
+				navigator().setRoot(viewController);
 			}
 		});
 	}
 		return (NavigationActivity) getCurrentActivity();
 	}
 
+	private Navigator navigator() {
+		return activity().getNavigator();
+	}
+
 	@NonNull
 	private LayoutFactory newLayoutFactory() {
 		return new LayoutFactory(activity(), reactInstanceManager, store);

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/Navigator.java

+package com.reactnativenavigation.viewcontrollers;
+
+import android.app.Activity;
+import android.view.View;
+import android.widget.FrameLayout;
+
+public class Navigator extends ViewController {
+	private boolean activityResumed = false;
+	private ViewController pendingViewControllerStart;
+
+	public Navigator(final Activity activity) {
+		super(activity);
+	}
+
+	@Override
+	protected View createView() {
+		FrameLayout view = new FrameLayout(getActivity());
+		return view;
+	}
+
+	public boolean isActivityResumed() {
+		return activityResumed;
+	}
+
+	public void setRoot(final ViewController viewController) {
+		getActivity().setContentView(viewController.getView());
+		if (activityResumed) {
+//			viewController.onStart();
+		} else {
+			pendingViewControllerStart = viewController;
+		}
+	}
+
+	public void onActivityCreated() {
+		getActivity().setContentView(getView());
+	}
+
+	public void onActivityResumed() {
+		activityResumed = true;
+		if (pendingViewControllerStart != null) {
+//			pendingViewControllerStart.onStart();
+			pendingViewControllerStart = null;
+		}
+	}
+
+	public void onActivityPaused() {
+		activityResumed = false;
+	}
+
+	public void onActivityDestroyed() {
+	}
+}

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/StackController.java

 	}
 
 	public void push(final ViewController child) {
-		ViewController previousTop = peek();
+		final ViewController previousTop = peek();
 
 		child.setStackController(this);
 		stack.push(child);
-		getView().addView(child.getView());
 
+		getView().addView(child.getView());
 		if (previousTop != null) {
 			getView().removeView(previousTop.getView());
 		}

lib/android/app/src/main/java/com/reactnativenavigation/viewcontrollers/ViewController.java

 	public View getView() {
 		if (view == null) {
 			view = createView();
-			onCreate();
 		}
 		return view;
 	}
-
-	public void onCreate() {
-
-	}
-
-	public void onStart() {
-
-	}
-
-	public void onStop() {
-
-	}
-
-	public void onDestroy() {
-
-	}
-
 }

lib/android/app/src/test/java/com/reactnativenavigation/viewcontrollers/NavigatorTest.java

+package com.reactnativenavigation.viewcontrollers;
+
+import android.app.Activity;
+
+import com.reactnativenavigation.BaseTest;
+import com.reactnativenavigation.mocks.SimpleViewController;
+
+import org.junit.Test;
+
+import static org.assertj.core.api.Java6Assertions.assertThat;
+import static org.mockito.Mockito.spy;
+
+public class NavigatorTest extends BaseTest {
+	private Activity activity;
+	private Navigator uut;
+	private SimpleViewController viewController;
+
+	@Override
+	public void beforeEach() {
+		super.beforeEach();
+		activity = newActivity();
+		viewController = spy(new SimpleViewController(activity, "simpleViewController"));
+		uut = new Navigator(activity);
+	}
+
+
+	@Test
+	public void isActivityRusumed() throws Exception {
+		assertThat(uut.isActivityResumed()).isFalse();
+		uut.onActivityCreated();
+		assertThat(uut.isActivityResumed()).isFalse();
+		uut.onActivityResumed();
+		assertThat(uut.isActivityResumed()).isTrue();
+		uut.onActivityPaused();
+		assertThat(uut.isActivityResumed()).isFalse();
+	}
+}