handleBack in navigator and bottomtabs

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

 	private final String name;
 	private final ReactInstanceManager reactInstanceManager;
 	private boolean attachedToReactInstance = false;
+	private ReactRootView reactRootView;
 
 	public ReactRootViewController(final Activity activity, final String id, final String name, final ReactInstanceManager reactInstanceManager) {
 		super(activity, id);
 		this.reactInstanceManager = reactInstanceManager;
 	}
 
-//	@Override
-//	public void destroy() {
-//		reactRootView.unmountReactApplication();
-//	}
+	@Override
+	public void onDestroy() {
+		super.onDestroy();
+		if (reactRootView != null) reactRootView.unmountReactApplication();
+		reactRootView = null;
+	}
 
 	@Override
 	public void onAppear() {
 	@NonNull
 	@Override
 	protected View createView() {
-		ReactRootView reactRootView = new ReactRootView(getActivity());
+		reactRootView = new ReactRootView(getActivity());
 		Bundle opts = new Bundle();
 		opts.putString("id", getId());
 		reactRootView.startReactApplication(this.reactInstanceManager, this.name, opts);

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

 		return root;
 	}
 
+	@Override
+	public boolean handleBack() {
+		return !tabs.isEmpty() && tabs.get(selectedIndex).handleBack();
+	}
+
 	@Override
 	public boolean onNavigationItemSelected(@NonNull final MenuItem item) {
 		selectTabAtIndex(item.getItemId());

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

 		//
 	}
 
+	@Override
+	public boolean handleBack() {
+		return root != null && root.handleBack();
+	}
+
 	/*
 	 * Navigation methods
 	 */

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

 			@Override
 			public void run() {
 				getView().removeView(poppedTop.getView());
-				poppedTop.destroy();
+				poppedTop.onDestroy();
 			}
 		});
 	}
 			pop();
 		} else {
 			stack.remove(childController.getId());
-			childController.destroy();
+			childController.onDestroy();
 		}
 	}
 

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

 		//
 	}
 
-	public void destroy() {
-		getView().getViewTreeObserver().removeOnGlobalLayoutListener(this);
+	public void onDestroy() {
+		view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
 		view = null;
 	}
 

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

 import java.util.List;
 
 import static org.assertj.core.api.Java6Assertions.assertThat;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 public class BottomTabsControllerTest extends BaseTest {
 
 		assertThat(uut.findControllerById(child1.getId())).isEqualTo(child1);
 	}
 
+	@Test
+	public void handleBack_DelegatesToSelectedChild() throws Exception {
+		assertThat(uut.handleBack()).isFalse();
+
+		List<ViewController> tabs = createTabs();
+		ViewController spy = spy(tabs.get(2));
+		tabs.set(2, spy);
+		when(spy.handleBack()).thenReturn(true);
+		uut.setTabs(tabs);
+
+		assertThat(uut.handleBack()).isFalse();
+		uut.selectTabAtIndex(2);
+		assertThat(uut.handleBack()).isTrue();
+
+		verify(spy, times(1)).handleBack();
+	}
+
 	@NonNull
 	private List<ViewController> createTabs() {
 		return Arrays.asList(child1, child2, child3, child4, child5);

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

 import java.util.Arrays;
 
 import static org.assertj.core.api.Java6Assertions.assertThat;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
 
 public class NavigatorTest extends BaseTest {
 	private Activity activity;
 		assertThat(stack2.getChildControllers()).containsOnly(child2);
 	}
 
+	@Test
+	public void handleBack_DelegatesToRoot() throws Exception {
+		assertThat(uut.handleBack()).isFalse();
+		ViewController spy = spy(child1);
+		uut.setRoot(spy);
+		when(spy.handleBack()).thenReturn(true);
+		assertThat(uut.handleBack()).isTrue();
+		verify(spy, times(1)).handleBack();
+	}
+
 	@NonNull
 	private BottomTabsController newTabs() {
 		return new BottomTabsController(activity, "tabsController");

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

 		uut.push(child2);
 		uut.push(child3);
 
-		verify(child3, times(0)).destroy();
+		verify(child3, times(0)).onDestroy();
 		uut.pop();
-		verify(child3, times(1)).destroy();
+		verify(child3, times(1)).onDestroy();
 	}
 
 	@Test
 		uut.push(child2);
 		uut.push(child3);
 
-		verify(child2, times(0)).destroy();
+		verify(child2, times(0)).onDestroy();
 		uut.popSpecific(child2);
-		verify(child2, times(1)).destroy();
+		verify(child2, times(1)).onDestroy();
 	}
 
 	@Test
 		uut.push(child2);
 		uut.push(child3);
 
-		verify(child2, times(0)).destroy();
-		verify(child3, times(0)).destroy();
+		verify(child2, times(0)).onDestroy();
+		verify(child3, times(0)).onDestroy();
 		uut.popTo(child1);
-		verify(child2, times(1)).destroy();
-		verify(child3, times(1)).destroy();
+		verify(child2, times(1)).onDestroy();
+		verify(child3, times(1)).onDestroy();
 	}
 
 	private void assertHasSingleChildViewOfController(ViewController childController) {

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

 import org.junit.Test;
 import org.robolectric.Shadows;
 
+import java.lang.reflect.Field;
+
 import static org.assertj.core.api.Java6Assertions.assertThat;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 		spy.getView().getViewTreeObserver().dispatchOnGlobalLayout();
 		verify(spy, times(1)).onDisappear();
 	}
+
+	@Test
+	public void onDestroy_RemovesGlobalLayoutListener() throws Exception {
+		ViewController spy = spy(uut);
+		View view = spy.getView();
+		Shadows.shadowOf(view).setMyParent(mock(ViewParent.class));
+
+		spy.onDestroy();
+
+		Assertions.assertThat(view).isShown();
+		view.getViewTreeObserver().dispatchOnGlobalLayout();
+		verify(spy, times(0)).onAppear();
+		verify(spy, times(0)).onDisappear();
+	}
+
+	@Test
+	public void onDestroy_NullifiesTheView() throws Exception {
+		assertThat(uut.getView()).isNotNull();
+		uut.onDestroy();
+		Field field = ViewController.class.getDeclaredField("view");
+		field.setAccessible(true);
+		assertThat(field.get(uut)).isNull();
+	}
 }