[Android] Bottom tab not update (#275)

Fixes #259

Issue
Screen doesn't update when switching between tabs.

Problem
When ScreenContainer re-added. mFragmentManager is destroyed.

android/src/main/java/com/swmansion/rnscreens/ScreenContainer.java

@@ -235,10 +235,24 @@ protected boolean hasScreen(ScreenFragment screenFragment) {
     return mScreenFragments.contains(screenFragment);
   }
 
+  protected void ensureFragmentManager() {
+    if (mFragmentManager != null && mFragmentManager.isDestroyed()) {
+      // When fragmentManager is destroyed, try to remove current fragment's views
+      for (int i = 0, size = mScreenFragments.size(); i < size; i++) {
+        ScreenFragment screenFragment = mScreenFragments.get(i);
+        removeView(screenFragment.getScreenRootView());
+      }
+      mFragmentManager = null;
+      mActiveScreenFragments.clear();
+      mNeedUpdate = true;
+    }
+  }
+
   @Override
   protected void onAttachedToWindow() {
     super.onAttachedToWindow();
     mIsAttached = true;
+    ensureFragmentManager();
     updateIfNeeded();
   }
 

android/src/main/java/com/swmansion/rnscreens/ScreenFragment.java

@@ -1,11 +1,13 @@
 package com.swmansion.rnscreens;
 
 import android.annotation.SuppressLint;
+import android.content.Context;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.fragment.app.Fragment;
 
@@ -33,6 +35,10 @@ public View onCreateView(LayoutInflater inflater,
     return mScreenView;
   }
 
+  protected ViewGroup getScreenRootView() {
+    return mScreenView;
+  }
+
   public Screen getScreen() {
     return mScreenView;
   }

android/src/main/java/com/swmansion/rnscreens/ScreenStackFragment.java

@@ -96,6 +96,11 @@ public View onCreateView(LayoutInflater inflater,
     return mScreenRootView;
   }
 
+  @Override
+  protected ViewGroup getScreenRootView() {
+    return mScreenRootView;
+  }
+
   public boolean isDismissable() {
     View child = mScreenView.getChildAt(0);
     if (child instanceof ScreenStackHeaderConfig) {