From f2aaac3285130675ea6c3429b5a7675ec47d8555 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Paczos?= <lukas.paczos@gmail.com>
Date: Tue, 22 Jan 2019 16:06:39 +0100
Subject: [android] fix ViewPagerActivity style not loading after rotation

---
 .../activity/fragment/ViewPagerActivity.java       | 41 +++++++++++++++++++---
 1 file changed, 37 insertions(+), 4 deletions(-)

diff --git a/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/fragment/ViewPagerActivity.java b/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/fragment/ViewPagerActivity.java
index 63c63b690e..c494842b14 100644
--- a/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/fragment/ViewPagerActivity.java
+++ b/platform/android/MapboxGLAndroidSDKTestApp/src/main/java/com/mapbox/mapboxsdk/testapp/activity/fragment/ViewPagerActivity.java
@@ -3,9 +3,10 @@ package com.mapbox.mapboxsdk.testapp.activity.fragment;
 import android.os.Bundle;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
-import android.support.v4.app.FragmentPagerAdapter;
+import android.support.v4.app.FragmentStatePagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.support.v7.app.AppCompatActivity;
+
 import com.mapbox.mapboxsdk.camera.CameraPosition;
 import com.mapbox.mapboxsdk.geometry.LatLng;
 import com.mapbox.mapboxsdk.maps.MapboxMapOptions;
@@ -18,19 +19,51 @@ import com.mapbox.mapboxsdk.testapp.R;
  */
 public class ViewPagerActivity extends AppCompatActivity {
 
+  private ViewPager viewPager;
+  private MapFragmentAdapter adapter;
+
   @Override
   protected void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
     setContentView(R.layout.activity_viewpager);
 
-    ViewPager viewPager = (ViewPager) findViewById(R.id.viewpager);
+    viewPager = (ViewPager) findViewById(R.id.viewpager);
     if (viewPager != null) {
-      MapFragmentAdapter adapter = new MapFragmentAdapter(getSupportFragmentManager());
+      adapter = new MapFragmentAdapter(getSupportFragmentManager());
       viewPager.setAdapter(adapter);
     }
   }
 
-  static class MapFragmentAdapter extends FragmentPagerAdapter {
+  @Override
+  protected void onRestoreInstanceState(Bundle savedInstanceState) {
+    super.onRestoreInstanceState(savedInstanceState);
+
+    int currentPosition = viewPager.getCurrentItem();
+    SupportMapFragment mapFragment;
+
+    if (Math.abs(0 - currentPosition) <= 1) {
+      mapFragment = (SupportMapFragment) adapter.instantiateItem(viewPager, 0);
+      mapFragment.getMapAsync(mapboxMap -> {
+        mapboxMap.setStyle(Style.MAPBOX_STREETS);
+      });
+    }
+
+    if (Math.abs(1 - currentPosition) <= 1) {
+      mapFragment = (SupportMapFragment) adapter.instantiateItem(viewPager, 1);
+      mapFragment.getMapAsync(mapboxMap -> {
+        mapboxMap.setStyle(Style.DARK);
+      });
+    }
+
+    if (Math.abs(2 - currentPosition) <= 1) {
+      mapFragment = (SupportMapFragment) adapter.instantiateItem(viewPager, 2);
+      mapFragment.getMapAsync(mapboxMap -> {
+        mapboxMap.setStyle(Style.SATELLITE);
+      });
+    }
+  }
+
+  static class MapFragmentAdapter extends FragmentStatePagerAdapter {
 
     private static int NUM_ITEMS = 3;
 
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