Android: Support tab switching

android/app/src/main/java/com/reactnativenavigation/layout/LayoutFactory.java

@@ -9,6 +9,7 @@ import com.reactnativenavigation.layout.bottomtabs.BottomTabsCreator;
 import java.util.List;
 
 public class LayoutFactory {
+
     public interface RootViewCreator {
         View createRootView(String id, String name);
     }
@@ -49,7 +50,11 @@ public class LayoutFactory {
 
     private View createBottomTabs(LayoutNode node) {
         final BottomTabsContainer tabsContainer = new BottomTabsContainer(activity, bottomTabsCreator);
-        tabsContainer.setTabContent(create(node.children.get(0)));
+
+        for (LayoutNode child : node.children) {
+            final View tabContent = create(child);
+            tabsContainer.addTabContent(tabContent);
+        }
         return tabsContainer;
     }
 

android/app/src/main/java/com/reactnativenavigation/layout/bottomtabs/BottomTabs.java

@@ -2,36 +2,83 @@ package com.reactnativenavigation.layout.bottomtabs;
 
 import android.graphics.Color;
 import android.os.Build;
+import android.support.annotation.NonNull;
 import android.support.design.widget.BottomNavigationView;
+import android.view.Menu;
+import android.view.MenuItem;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.RelativeLayout;
 import android.widget.RelativeLayout.LayoutParams;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static android.widget.RelativeLayout.ALIGN_PARENT_BOTTOM;
 
-public class BottomTabs {
+public class BottomTabs implements BottomNavigationView.OnNavigationItemSelectedListener {
 
     private static final AtomicInteger viewId = new AtomicInteger(1);
 
     private BottomNavigationView bottomNavigationView;
+    private List<View> tabsContent;
+    private int currentTabId;
 
     public void attach(RelativeLayout parentLayout) {
-        bottomNavigationView = new BottomNavigationView(parentLayout.getContext());
-        bottomNavigationView.setId(generateViewId());
-        bottomNavigationView.setBackgroundColor(Color.DKGRAY);
+        createBottomNavigation(parentLayout);
+        addButtomNavigationToParent(parentLayout);
+        bottomNavigationView.setOnNavigationItemSelectedListener(this);
+        tabsContent = new ArrayList<>(bottomNavigationView.getMaxItemCount());
+    }
 
+    public void addTab(String label, View tabContent) {
+        int tabId = getTabsCount();
+        bottomNavigationView.getMenu().add(0, tabId, Menu.NONE, label);
+
+        attachTabContent(tabContent);
+        tabsContent.add(tabContent);
+
+        if (isFirstTabEver()) {
+            currentTabId = 0;
+            showCurrentTab();
+        } else {
+            hideTab(tabId);
+        }
+    }
+
+    public int getTabsCount() {
+        return bottomNavigationView.getMenu().size();
+    }
+
+    @Override
+    public boolean onNavigationItemSelected(@NonNull MenuItem item) {
+        final int id = item.getItemId();
+
+        hideCurrentTab();
+        currentTabId = id;
+        showCurrentTab();
+        return true;
+    }
+
+    private void addButtomNavigationToParent(RelativeLayout parentLayout) {
         LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
         lp.addRule(ALIGN_PARENT_BOTTOM);
         bottomNavigationView.setLayoutParams(lp);
         parentLayout.addView(bottomNavigationView, lp);
     }
 
-    public void addTab(String label, View tabContent) {
-        bottomNavigationView.getMenu().add(label);
+    private void createBottomNavigation(RelativeLayout parentLayout) {
+        bottomNavigationView = new BottomNavigationView(parentLayout.getContext());
+        bottomNavigationView.setId(generateViewId());
+        bottomNavigationView.setBackgroundColor(Color.DKGRAY);
+    }
+
+    private boolean isFirstTabEver() {
+        return bottomNavigationView.getMenu().size() == 1;
+    }
 
+    private void attachTabContent(View tabContent) {
         LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
         params.addRule(RelativeLayout.ABOVE, bottomNavigationView.getId());
 
@@ -39,6 +86,18 @@ public class BottomTabs {
         parent.addView(tabContent, params);
     }
 
+    private void showCurrentTab() {
+        tabsContent.get(currentTabId).setVisibility(View.VISIBLE);
+    }
+
+    private void hideCurrentTab() {
+        hideTab(currentTabId);
+    }
+
+    private void hideTab(int tabId) {
+        tabsContent.get(tabId).setVisibility(View.GONE);
+    }
+
     private int generateViewId() {
         if (Build.VERSION.SDK_INT >= 17) {
             return View.generateViewId();

android/app/src/main/java/com/reactnativenavigation/layout/bottomtabs/BottomTabsContainer.java

@@ -13,8 +13,8 @@ public class BottomTabsContainer extends RelativeLayout {
         createBottomTabs(bottomTabsCreator);
     }
 
-    public void setTabContent(View tabContent) {
-        bottomTabs.addTab("#0", tabContent);
+    public void addTabContent(View tabContent) {
+        bottomTabs.addTab("#" + bottomTabs.getTabsCount(), tabContent);
     }
 
     private void createBottomTabs(BottomTabsCreator bottomTabsCreator) {

android/app/src/test/java/com/reactnativenavigation/LayoutFactoryTest.java

@@ -16,6 +16,7 @@ import com.reactnativenavigation.layout.bottomtabs.BottomTabsCreator;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
+import org.mockito.ArgumentCaptor;
 import org.robolectric.Robolectric;
 import org.robolectric.RobolectricTestRunner;
 
@@ -27,7 +28,6 @@ import java.util.List;
 
 import static org.assertj.core.api.Java6Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
-import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -44,12 +44,14 @@ public class LayoutFactoryTest {
 
     private Activity activity;
     private View mockView;
+    private View otherMockView;
     private LayoutFactory.RootViewCreator rootViewCreator;
 
     @Before
     public void setUp() {
         activity = Robolectric.buildActivity(AppCompatActivity.class).get();
         mockView = new View(activity);
+        otherMockView = new View(activity);
         rootViewCreator = mock(LayoutFactory.RootViewCreator.class);
     }
 
@@ -68,7 +70,7 @@ public class LayoutFactoryTest {
     public void returnsContainerStack() throws Exception {
         when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView);
         final LayoutNode containerNode = createContainerNode();
-        final LayoutNode stackNode = getContainerStackNode(containerNode);
+        final LayoutNode stackNode = createContainerStackNode(containerNode);
 
         final ViewGroup result = (ViewGroup) createLayoutFactory().create(stackNode);
 
@@ -86,7 +88,7 @@ public class LayoutFactoryTest {
 
         final LayoutNode containerNode1 = createContainerNode(VIEW_ID, VIEW_NAME);
         final LayoutNode containerNode2 = createContainerNode(OTHER_VIEW_ID, OTHER_VIEW_NAME);
-        final LayoutNode stackNode = getContainerStackNode(Arrays.asList(containerNode1, containerNode2));
+        final LayoutNode stackNode = createContainerStackNode(containerNode1, containerNode2);
 
         final ViewGroup result = (ViewGroup) createLayoutFactory().create(stackNode);
 
@@ -101,14 +103,41 @@ public class LayoutFactoryTest {
     @Test
     public void returnsSingleTabContent() throws Exception {
         BottomTabs bottomTabsMock = mock(BottomTabs.class);
+        when(bottomTabsMock.getTabsCount()).thenReturn(0);
+
         when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView);
         final LayoutNode containerNode = createContainerNode();
         final LayoutNode tabNode = createTabNode(containerNode);
 
         final View result = createLayoutFactory(bottomTabsMock).create(tabNode);
 
+        assertThat(result).isInstanceOf(BottomTabsContainer.class);
+
+        ArgumentCaptor<Container> containerCaptor = ArgumentCaptor.forClass(Container.class);
+        verify(bottomTabsMock).addTab(eq("#0"), containerCaptor.capture());
+        Container container = containerCaptor.getValue();
+        View view = assertViewChildrenCount(container, 1).get(0);
+        assertThat(view).isEqualTo(mockView);
+    }
+
+    @Test
+    public void returnsTwoTabContent() throws Exception {
+        BottomTabs bottomTabsMock = mock(BottomTabs.class);
+        when(bottomTabsMock.getTabsCount()).thenReturn(0, 1);
+
+        when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView);
+        final LayoutNode firstTabRootNode = createContainerNode(VIEW_ID, VIEW_NAME);
+
+        when(rootViewCreator.createRootView(eq(OTHER_VIEW_ID), eq(OTHER_VIEW_NAME))).thenReturn(otherMockView);
+        final LayoutNode secondTabRootNode = createContainerStackNode(createContainerNode(OTHER_VIEW_ID, OTHER_VIEW_NAME));
+
+        final LayoutNode tabNode = createTabNode(firstTabRootNode, secondTabRootNode);
+
+        final View result = createLayoutFactory(bottomTabsMock).create(tabNode);
+
         assertThat(result).isInstanceOf(BottomTabsContainer.class);
         verify(bottomTabsMock).addTab(eq("#0"), any(Container.class));
+        verify(bottomTabsMock).addTab(eq("#1"), any(ContainerStack.class));
     }
 
     @Test(expected = IllegalArgumentException.class)
@@ -141,18 +170,14 @@ public class LayoutFactoryTest {
         return new LayoutNode(id, "Container", new HashMap<String, Object>() {{ put("name", name); }});
     }
 
-    private LayoutNode getContainerStackNode(LayoutNode innerNode) {
-        return getContainerStackNode(Arrays.asList(innerNode));
-    }
-
-    private LayoutNode getContainerStackNode(List<LayoutNode> children) {
+    private LayoutNode createContainerStackNode(LayoutNode... children) {
         LayoutNode node = new LayoutNode();
         node.type = "ContainerStack";
-        node.children = children;
+        node.children = Arrays.asList(children);
         return node;
     }
 
-    private LayoutNode createTabNode(LayoutNode children) {
+    private LayoutNode createTabNode(LayoutNode... children) {
         LayoutNode node = new LayoutNode();
         node.type = "BottomTabs";
         node.children = Arrays.asList(children);