[Android] Add ability to start app with deep stack (#2761)

For example, the following code will start a single screen app with two
screens pushed into the stack.

```js
Navigation.startSingleScreenApp({
    components: [
    {
      screen: 'example.Types',
      title: 'Navigation Types',
      overrideBackPress: true
    },
    {
      screen: 'example.Types.CustomButtonScreen',
      title: 'Custom Buttons'
    }
  ]
});
```

android/app/src/main/java/com/reactnativenavigation/layouts/BottomTabsLayout.java

         ScreenParams screenParams = params.tabParams.get(position);
         ScreenStack newStack = new ScreenStack(getActivity(), getScreenStackParent(), screenParams.getNavigatorId(), this);
         newStack.pushInitialScreen(screenParams, createScreenLayoutParams(screenParams));
+        for (ScreenParams screen : screenParams.screens) {
+            newStack.pushInitialScreen(screen, createScreenLayoutParams(screen));
+        }
         screenStacks[position] = newStack;
     }
 

android/app/src/main/java/com/reactnativenavigation/layouts/SingleScreenLayout.java

         stack = new ScreenStack(getActivity(), parent, screenParams.getNavigatorId(), this);
         LayoutParams lp = new LayoutParams(MATCH_PARENT, MATCH_PARENT);
         pushInitialScreen(lp);
+        pushAdditionalScreens(lp);
+        stack.show(NavigationType.Push);
     }
 
     protected void pushInitialScreen(LayoutParams lp) {
         stack.pushInitialScreen(screenParams, lp);
-        stack.show(NavigationType.Push);
+    }
+
+    private void pushAdditionalScreens(LayoutParams lp) {
+        for (ScreenParams screen : screenParams.screens) {
+            stack.pushInitialScreen(screen, lp);
+        }
     }
 
     private void sendScreenChangedEventAfterInitialPush() {

android/app/src/main/java/com/reactnativenavigation/params/ScreenParams.java

 package com.reactnativenavigation.params;
 
+import java.util.Collections;
 import java.util.List;
 
 public class ScreenParams extends BaseScreenParams {
     public String tabLabel;
     public List<PageParams> topTabParams;
     public List<String> sharedElementsTransitions;
+    public List<ScreenParams> screens = Collections.EMPTY_LIST; // used to init a stack with multiple screens
 
     public boolean hasTopTabs() {
         return topTabParams != null && !topTabParams.isEmpty();

android/app/src/main/java/com/reactnativenavigation/params/parsers/ScreenParamsParser.java

         result.leftButton = ButtonParser.parseLeftButton(params);
 
         result.topTabParams = parseTopTabs(params);
+        if (hasKey(params, "screens")) {
+            result.screens = parseScreens(params.getBundle("screens"));
+        }
 
         if (hasKey(params, FRAGMENT_CREATOR_CLASS_NAME)) {
             result.fragmentCreatorClassName = params.getString(FRAGMENT_CREATOR_CLASS_NAME);
             }
         });
     }
+
+    private static List<ScreenParams> parseScreens(Bundle screens) {
+        return new Parser().parseBundle(screens, new ParseStrategy<ScreenParams>() {
+            @Override
+            public ScreenParams parse(Bundle screen) {
+                return ScreenParamsParser.parse(screen);
+            }
+        });
+    }
 }

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

     public void pushInitialScreen(ScreenParams initialScreenParams, LayoutParams params) {
         Screen initialScreen = ScreenFactory.create(activity, initialScreenParams, leftButtonOnClickListener);
         initialScreen.setVisibility(View.INVISIBLE);
+        removeCurrentScreen();
         addScreen(initialScreen, params);
     }
 
+    private void removeCurrentScreen() {
+        if (!stack.empty()) parent.removeView(peek());
+    }
+
     public void push(final ScreenParams params, LayoutParams layoutParams, Promise onPushComplete) {
         Screen nextScreen = ScreenFactory.create(activity, params, leftButtonOnClickListener);
         final Screen previousScreen = stack.peek();

src/deprecated/platformSpecificDeprecated.android.js

 import * as newPlatformSpecific from './../platformSpecific';
 
 async function startSingleScreenApp(params) {
-  const screen = params.screen;
-  if (!screen.screen) {
+  const components = params.components;
+  if (!params.screen && !components) {
     console.error('startSingleScreenApp(params): screen must include a screen property');
     return;
   }
+
+  if (components) {
+    params.screen = createSingleScreen(components[0]);
+    components.shift();
+    params.screen.screens = components.map(createSingleScreen);
+  } else {
+    params.screen = createSingleScreen(params.screen);
+  }
+
+  params.sideMenu = convertDrawerParamsToSideMenuParams(params.drawer);
+  params.overrideBackPress = params.screen.overrideBackPress;
+  params.animateShow = convertAnimationType(params.animationType);
+  params.appStyle = convertStyleParams(params.appStyle);
+    if (params.appStyle) {
+      params.appStyle.orientation = getOrientation(params);
+    }
+
+  return await newPlatformSpecific.startApp(params);
+}
+
+function createSingleScreen(params) {
+  let screen = params;
   addNavigatorParams(screen);
   addNavigatorButtons(screen, params.drawer);
   addNavigationStyleParams(screen);
   screen.passProps = params.passProps;
-
   /*
    * adapt to new API
    */
   adaptTopTabs(screen, screen.navigatorID);
   screen.screenId = screen.screen;
-  params.screen = adaptNavigationStyleToScreenStyle(screen);
-  params.screen = adaptNavigationParams(screen);
-  params.appStyle = convertStyleParams(params.appStyle);
-  if (params.appStyle) {
-    params.appStyle.orientation = getOrientation(params);
-  }
-  params.sideMenu = convertDrawerParamsToSideMenuParams(params.drawer);
-  params.overrideBackPress = screen.overrideBackPress;
-  params.animateShow = convertAnimationType(params.animationType);
-
-  return await newPlatformSpecific.startApp(params);
+  screen = adaptNavigationStyleToScreenStyle(screen);
+  screen = adaptNavigationParams(screen);
+  return screen;
 }
 
 function getOrientation(params) {
   params.tabs = _.cloneDeep(params.tabs);
 
   params.tabs.forEach(function(tab, idx) {
-    addNavigatorParams(tab, null, idx);
-    addNavigatorButtons(tab, params.drawer);
-    addNavigationStyleParams(tab);
-    addTabIcon(tab);
-    if (!tab.passProps) {
-      tab.passProps = params.passProps;
+    if (tab.components) {
+      const components = tab.components;
+      const screen = createBottomTabScreen(components[0], idx, params)
+      const {label, icon} = components[0];
+      components.shift();
+      console.log('guyca', `${JSON.stringify(components[0])}`);
+      screen.screens = components.map(c => createBottomTabScreen({...c, icon, label}, idx, params));
+      
+      newTabs.push(screen);
+    } else {
+      newTabs.push(createBottomTabScreen(tab, idx, params));
     }
-
-    adaptTopTabs(tab, tab.navigatorID);
-
-    tab.screenId = tab.screen;
-
-    let newtab = adaptNavigationStyleToScreenStyle(tab);
-    newtab = adaptNavigationParams(tab);
-    newtab.overrideBackPress = tab.overrideBackPress;
-    newtab.timestamp = Date.now();
-    newTabs.push(newtab);
   });
   params.tabs = newTabs;
 
   return await newPlatformSpecific.startApp(params);
 }
 
+function createBottomTabScreen(tab, idx, params) {
+  addNavigatorParams(tab, null, idx);
+  addNavigatorButtons(tab, params.drawer);
+  addNavigationStyleParams(tab);
+  addTabIcon(tab);
+  if (!tab.passProps) {
+    tab.passProps = params.passProps;
+  }
+
+  adaptTopTabs(tab, tab.navigatorID);
+
+  tab.screenId = tab.screen;
+
+  let newtab = adaptNavigationStyleToScreenStyle(tab);
+  newtab = adaptNavigationParams(tab);
+  newtab.overrideBackPress = tab.overrideBackPress;
+  newtab.timestamp = Date.now();
+  return newtab;
+};
+
 function addTabIcon(tab) {
   if (tab.icon) {
     const icon = resolveAssetSource(tab.icon);
 }
 
 function addNavigatorButtons(screen, sideMenuParams) {
-
   const Screen = Navigation.getRegisteredScreen(screen.screen);
   if (screen.navigatorButtons == null) {
     screen.navigatorButtons = _.cloneDeep(Screen.navigatorButtons);