Android: Set bottom tabs layout over tabs content

android/app/deprecated/java/com/reactnativenavigation/utils/ViewUtils.java

         return pixels * scaledDensity;
     }
 
+    public static float getScreenHeight() {
+        WindowManager wm = (WindowManager) NavigationApplication.instance.getSystemService(Context.WINDOW_SERVICE);
+        DisplayMetrics metrics = new DisplayMetrics();
+        wm.getDefaultDisplay().getMetrics(metrics);
+        return metrics.heightPixels;
+    }
+
     public static int generateViewId() {
         if (Build.VERSION.SDK_INT >= 17) {
             return View.generateViewId();
         }
     }
 
-    public static float getScreenHeight() {
-        WindowManager wm = (WindowManager) NavigationApplication.instance.getSystemService(Context.WINDOW_SERVICE);
-        DisplayMetrics metrics = new DisplayMetrics();
-        wm.getDefaultDisplay().getMetrics(metrics);
-        return metrics.heightPixels;
-    }
-
     private static int compatGenerateViewId() {
         for (; ; ) {
             final int result = viewId.get();

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

 package com.reactnativenavigation.layout.bottomtabs;
 
+import android.graphics.Color;
+import android.os.Build;
 import android.support.design.widget.BottomNavigationView;
+import android.view.View;
+import android.view.ViewGroup;
 import android.widget.RelativeLayout;
+import android.widget.RelativeLayout.LayoutParams;
+
+import java.util.concurrent.atomic.AtomicInteger;
 
 import static android.widget.RelativeLayout.ALIGN_PARENT_BOTTOM;
 
 public class BottomTabs {
 
+    private static final AtomicInteger viewId = new AtomicInteger(1);
+
     private BottomNavigationView bottomNavigationView;
 
     public void attach(RelativeLayout parentLayout) {
         bottomNavigationView = new BottomNavigationView(parentLayout.getContext());
+        bottomNavigationView.setId(generateViewId());
+        bottomNavigationView.setBackgroundColor(Color.DKGRAY);
 
-        RelativeLayout.LayoutParams lp =
-                new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.MATCH_PARENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
+        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) {
+    public void addTab(String label, View tabContent) {
         bottomNavigationView.getMenu().add(label);
+
+        LayoutParams params = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
+        params.addRule(RelativeLayout.ABOVE, bottomNavigationView.getId());
+
+        ViewGroup parent = (ViewGroup) bottomNavigationView.getParent();
+        parent.addView(tabContent, params);
+    }
+
+    private int generateViewId() {
+        if (Build.VERSION.SDK_INT >= 17) {
+            return View.generateViewId();
+        } else {
+            return compatGenerateViewId();
+        }
+    }
+
+    private int compatGenerateViewId() {
+        while(true) {
+            final int result = viewId.get();
+            // aapt-generated IDs have the high byte nonzero; clamp to the range under that.
+            int newValue = result + 1;
+            if (newValue > 0x00FFFFFF) newValue = 1; // Roll over to 1, not 0.
+            if (viewId.compareAndSet(result, newValue)) {
+                return result;
+            }
+        }
     }
 }

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

         createBottomTabs(bottomTabsCreator);
     }
 
-    public void setTabContent(View tab) {
-        bottomTabs.addTab("#0");
-
-        LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
-        addView(tab, lp);
+    public void setTabContent(View tabContent) {
+        bottomTabs.addTab("#0", tabContent);
     }
 
     private void createBottomTabs(BottomTabsCreator bottomTabsCreator) {

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

 import android.view.View;
 import android.view.ViewGroup;
 
-import com.reactnativenavigation.layout.bottomtabs.BottomTabs;
-import com.reactnativenavigation.layout.bottomtabs.BottomTabsContainer;
 import com.reactnativenavigation.layout.Container;
 import com.reactnativenavigation.layout.ContainerStack;
 import com.reactnativenavigation.layout.LayoutFactory;
 import com.reactnativenavigation.layout.LayoutNode;
+import com.reactnativenavigation.layout.bottomtabs.BottomTabs;
+import com.reactnativenavigation.layout.bottomtabs.BottomTabsContainer;
 import com.reactnativenavigation.layout.bottomtabs.BottomTabsCreator;
 
 import org.junit.Before;
 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;
 import static org.mockito.Mockito.when;
 
 @RunWith(RobolectricTestRunner.class)
     }
 
     @Test
-    public void returnsContainerStack() throws Exception  {
+    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);
     }
 
     @Test
-    public void returnsContainerStackWithMultipleViews() throws Exception  {
+    public void returnsContainerStackWithMultipleViews() throws Exception {
         final View mockView1 = mock(View.class);
         final View mockView2 = mock(View.class);
         when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView1);
 
     @Test
     public void returnsSingleTabContent() throws Exception {
+        BottomTabs bottomTabsMock = mock(BottomTabs.class);
         when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView);
         final LayoutNode containerNode = createContainerNode();
         final LayoutNode tabNode = createTabNode(containerNode);
 
-        final View result = createLayoutFactory().create(tabNode);
+        final View result = createLayoutFactory(bottomTabsMock).create(tabNode);
 
         assertThat(result).isInstanceOf(BottomTabsContainer.class);
-        View containerView = assertViewChildrenCount((BottomTabsContainer) result, 1).get(0);
-        assertThat(containerView).isInstanceOf(Container.class);
-        assertViewChildren((Container) containerView, mockView);
+        verify(bottomTabsMock).addTab(eq("#0"), any(Container.class));
     }
 
     @Test(expected = IllegalArgumentException.class)
-    public void throwsExceptionForUnknownType() throws Exception  {
+    public void throwsExceptionForUnknownType() throws Exception {
         when(rootViewCreator.createRootView(eq(VIEW_ID), eq(VIEW_NAME))).thenReturn(mockView);
         final LayoutNode node = new LayoutNode(VIEW_ID, "***unknownType***", Collections.<String, Object>emptyMap());
 
     }
 
     private LayoutFactory createLayoutFactory() {
-        BottomTabs bottomTabs = mock(BottomTabs.class);
-        BottomTabsCreator bottomTabsCreator = mock(BottomTabsCreator.class);
-        when(bottomTabsCreator.create()).thenReturn(bottomTabs);
+        return createLayoutFactory(null);
+    }
+
+    private LayoutFactory createLayoutFactory(BottomTabs bottomTabs) {
+        BottomTabsCreator bottomTabsCreator = null;
+        if (bottomTabs != null) {
+            bottomTabsCreator = mock(BottomTabsCreator.class);
+            when(bottomTabsCreator.create()).thenReturn(bottomTabs);
+        }
+
         return new LayoutFactory(activity, rootViewCreator, bottomTabsCreator);
     }