Started implementation of ScreenStack

android/app/src/main/java/com/reactnativenavigation/activities/BaseReactActivity.java

 import com.facebook.react.shell.MainReactPackage;
 import com.reactnativenavigation.BuildConfig;
 import com.reactnativenavigation.core.RctManager;
+import com.reactnativenavigation.core.objects.Screen;
 import com.reactnativenavigation.packages.RnnPackage;
 import com.reactnativenavigation.utils.ContextProvider;
 
 /**
  * Base Activity for React Native applications.
  */
-public class BaseReactActivity extends AppCompatActivity implements DefaultHardwareBackBtnHandler {
+public abstract class BaseReactActivity extends AppCompatActivity implements DefaultHardwareBackBtnHandler {
 
     private static final String TAG = "BaseReactActivity";
     private static final String REDBOX_PERMISSION_MESSAGE =
         }
     }
 
+    public abstract void push(Screen screen);
+
     @Override
     public boolean onCreateOptionsMenu(Menu menu) {
         mMenu = menu;

android/app/src/main/java/com/reactnativenavigation/activities/RootActivity.java

 import com.facebook.react.ReactRootView;
 import com.reactnativenavigation.R;
 import com.reactnativenavigation.core.RctManager;
+import com.reactnativenavigation.core.objects.Screen;
 
 /**
  * Created by guyc on 13/04/16.
         super.onPause();
         finish();
     }
+
+    public void push(Screen screen) {
+        //TODO
+    }
 }

android/app/src/main/java/com/reactnativenavigation/activities/SingleScreenActivity.java

 package com.reactnativenavigation.activities;
 
 import android.support.v7.widget.Toolbar;
-import android.view.View;
 import android.widget.FrameLayout;
 
 import com.reactnativenavigation.R;
 import com.reactnativenavigation.core.RctManager;
 import com.reactnativenavigation.core.objects.Screen;
-import com.reactnativenavigation.views.RctView;
+import com.reactnativenavigation.views.ScreenStack;
 
 /**
  * Created by guyc on 05/04/16.
 
     private Toolbar mToolbar;
     private FrameLayout mContentFrame;
+    private ScreenStack screenStack;
 
     @Override
     protected void handleOnCreate() {
 
         Screen screen = (Screen) getIntent().getSerializableExtra(EXTRA_SCREEN);
         setupToolbar(screen.title);
-        setupReactView(screen);
+
+        screenStack = new ScreenStack(this);
+        mContentFrame.addView(screenStack);
+        screenStack.push(screen);
     }
 
     private void setupToolbar(String title) {
         mToolbar.setTitle(title);
     }
-
-    private void setupReactView(Screen screen) {
-        View view = new RctView(this, mReactInstanceManager, screen);
-        mContentFrame.addView(view);
+    
+    @Override
+    public void push(Screen screen) {
+        screenStack.push(screen);
     }
 }

android/app/src/main/java/com/reactnativenavigation/activities/TabActivity.java

     private ViewPager mViewPager;
 
     private ArrayList<Screen> mScreens;
+    private ViewPagerAdapter adapter;
 
     @Override
     protected void handleOnCreate() {
         setupViewPager();
     }
 
+    @Override
+    public void push(Screen screen) {
+        adapter.pushScreen(screen);
+    }
+
     private void setupToolbar() {
         setSupportActionBar(mToolbar);
         mToolbar.setScreens(mScreens);
     }
 
     private void setupViewPager() {
-        ViewPagerAdapter adapter = new ViewPagerAdapter(this, mViewPager, mToolbar, mScreens);
+        adapter = new ViewPagerAdapter(this, mViewPager, mToolbar, mScreens);
         mViewPager.setAdapter(adapter);
         mTabLayout.setupWithViewPager(mViewPager);
         mTabLayout.setOnTabSelectedListener(adapter);

android/app/src/main/java/com/reactnativenavigation/adapters/ViewPagerAdapter.java

 import com.reactnativenavigation.activities.BaseReactActivity;
 import com.reactnativenavigation.core.RctManager;
 import com.reactnativenavigation.core.objects.Screen;
-import com.reactnativenavigation.views.RctView;
-import com.reactnativenavigation.views.RnnToolBar;
+import com.reactnativenavigation.views.ScreenStack;
 
 import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.Map;
 
 /**
  * Created by guyc on 02/04/16.
 
     private BaseReactActivity mContext;
     private ViewPager mViewPager;
-    private RnnToolBar mToolbar;
-    private final ArrayList<Screen> mScreens;
+    private Toolbar mToolbar;
     private final ReactInstanceManager mReactInstanceManager;
+    private final ArrayList<ScreenStack> screenStacks;
+    private final Map<String, ScreenStack> stacksByNavId;
+
 
     public ViewPagerAdapter(BaseReactActivity context, ViewPager viewPager, RnnToolBar toolbar,
                             ArrayList<Screen> screens) {
         mContext = context;
         mViewPager = viewPager;
         mToolbar = toolbar;
-        mScreens = screens;
+        screenStacks = new ArrayList<>();
+        stacksByNavId  = new HashMap<>();
+        for(Screen screen: screens){
+            ScreenStack stack = new ScreenStack(context);
+            stack.push(screen);
+            screenStacks.add(stack);
+            stacksByNavId.put(screen.navigatorId, stack);
+        }
         mReactInstanceManager = RctManager.getInstance().getReactInstanceManager();
     }
 
+    public void pushScreen(Screen screen){
+        ScreenStack stack = stacksByNavId.get(screen.navigatorId);
+        stack.push(screen);
+    }
+
     @Override
     public Object instantiateItem(ViewGroup container, int position) {
-        Screen screen = mScreens.get(position);
-        View view = new RctView(mContext, mReactInstanceManager, screen);
+        ScreenStack view = screenStacks.get(position);
         container.addView(view);
         return view;
     }
 
     @Override
     public int getCount() {
-        return mScreens.size();
+        return screenStacks.size();
     }
 
     @Override
 
     @Override
     public CharSequence getPageTitle(int position) {
-        return mScreens.get(position).title;
+        return screenStacks.get(position).peek().title;
     }
 
     @Override
 
         // Send tab selected event
         WritableMap params = Arguments.createMap();
-        Screen screen = mScreens.get(position);
+        Screen screen = screenStacks.get(position).peek();
         params.putString(Screen.KEY_NAVIGATOR_EVENT_ID, screen.navigatorEventId);
 
         mToolbar.setupToolbarButtonsAsync(mScreens.get(position));

android/app/src/main/java/com/reactnativenavigation/modules/RctActivityModule.java

 import com.facebook.react.bridge.ReactMethod;
 import com.facebook.react.bridge.ReadableArray;
 import com.facebook.react.bridge.ReadableMap;
+import com.reactnativenavigation.activities.BaseReactActivity;
 import com.reactnativenavigation.activities.SingleScreenActivity;
 import com.reactnativenavigation.activities.TabActivity;
 import com.reactnativenavigation.core.objects.Screen;
         Activity context = ContextProvider.getActivityContext();
         if (context != null && !context.isFinishing()) {
             Intent intent = new Intent(context, TabActivity.class);
-
             Bundle extras = new Bundle();
             extras.putSerializable(TabActivity.EXTRA_SCREENS, createScreens(screens));
             intent.putExtras(extras);
-
             context.startActivity(intent);
         }
     }
 
     @ReactMethod
     public void startSingleScreenApp(ReadableMap screen) {
-        navigatorPush(screen);
-    }
-
-    @ReactMethod
-    public void navigatorPush(ReadableMap screen) {
-        Activity context = ContextProvider.getActivityContext();
+        BaseReactActivity context = ContextProvider.getActivityContext();
         if (context != null && !context.isFinishing()) {
             Intent intent = new Intent(context, SingleScreenActivity.class);
-
             Bundle extras = new Bundle();
             extras.putSerializable(SingleScreenActivity.EXTRA_SCREEN, new Screen(screen));
             intent.putExtras(extras);
-
             context.startActivity(intent);
         }
     }
+
+    @ReactMethod
+    public void navigatorPush(ReadableMap screen) {
+        BaseReactActivity context = ContextProvider.getActivityContext();
+         if (context != null && !context.isFinishing()) {
+             context.push(new Screen(screen));
+        }
+    }
 }

android/app/src/main/java/com/reactnativenavigation/utils/ContextProvider.java

 package com.reactnativenavigation.utils;
 
-import android.app.Activity;
 import android.support.annotation.Nullable;
 
+import com.reactnativenavigation.activities.BaseReactActivity;
+
 import java.lang.ref.WeakReference;
 
 /**
  * Created by guyc on 10/03/16.
  */
 public class ContextProvider {
-    private static WeakReference<Activity> sActivityWR;
+    private static WeakReference<BaseReactActivity> sActivityWR;
 
-    public static void setActivityContext(Activity activity) {
+    public static void setActivityContext(BaseReactActivity activity) {
         if (sActivityWR == null) {
             sActivityWR = new WeakReference<>(activity);
         }
     }
 
-    public static @Nullable Activity getActivityContext() {
+    public static @Nullable BaseReactActivity getActivityContext() {
         return sActivityWR != null ? sActivityWR.get() : null;
     }
 

android/app/src/main/java/com/reactnativenavigation/views/ScreenStack.java

+package com.reactnativenavigation.views;
+
+import android.animation.LayoutTransition;
+import android.widget.FrameLayout;
+
+import com.facebook.react.ReactInstanceManager;
+import com.reactnativenavigation.activities.BaseReactActivity;
+import com.reactnativenavigation.core.RctManager;
+import com.reactnativenavigation.core.objects.Screen;
+
+import java.util.Stack;
+
+import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;
+
+public class ScreenStack extends FrameLayout {
+
+    private class ScreenView{
+        Screen screen;
+        RctView view;
+
+        public ScreenView(Screen screen, RctView view) {
+            this.screen = screen;
+            this.view = view;
+        }
+    }
+
+    private final Stack<ScreenView> stack = new Stack<>();
+    private final ReactInstanceManager mReactInstanceManager = RctManager.getInstance().getReactInstanceManager();
+    private final BaseReactActivity reactActivity;
+
+    public ScreenStack(BaseReactActivity context){
+        super(context);
+        reactActivity = context;
+        setLayoutTransition(new LayoutTransition());
+    }
+
+    public void push(Screen screen){
+        RctView view = new RctView(reactActivity, mReactInstanceManager, screen);
+        addView(view, MATCH_PARENT, MATCH_PARENT);
+        stack.push(new ScreenView(screen, view));
+    }
+
+    public Screen pop(){
+        ScreenView popped = stack.pop();
+        removeView(popped.view);
+        return popped.screen;
+    }
+
+    public boolean isEmpty(){
+        return stack.isEmpty();
+    }
+
+    public int getStackSize(){
+        return stack.size();
+    }
+
+    public Screen peek(){
+        return stack.peek().screen;
+    }
+}