Handling gratefully screen rotation and configuration changes.

app/src/main/java/pl/tpolgrabia/urbanexplorer/MainActivity.java

@@ -5,6 +5,7 @@ import android.content.Intent;
 import android.location.Location;
 import android.location.LocationManager;
 import android.os.Bundle;
+import android.os.PersistableBundle;
 import android.provider.Settings;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
@@ -40,6 +41,7 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
     private static final int WIKI_FRAGMENT_ID = 1;
     private static final double MAX_FRAGMENT_ID = WIKI_FRAGMENT_ID;
     private static final double MIN_FRAGMENT_ID = HOME_FRAGMENT_ID;
+    private static final String FRAG_ID = "FRAG_ID";
     public static DisplayImageOptions options;
     private GestureDetectorCompat gestureDetector;
     private float SWIPE_THRESHOLD = 50;
@@ -67,7 +69,11 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
+        Log.v(CLASS_TAG, "onCreate");
         setContentView(R.layout.activity_main);
+
+        currentFragmentId = 0;
+
 //        Toolbar toolbar = (Toolbar) findViewById(R.id.navbar);
 //        setSupportActionBar(toolbar);
 
@@ -84,10 +90,10 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
 
         ImageLoader.getInstance().init(config);
 
-        getSupportFragmentManager()
+//        getSupportFragmentManager()
-            .beginTransaction()
+//            .beginTransaction()
-            .replace(R.id.fragments, new HomeFragment())
+//            .replace(R.id.fragments, new HomeFragment())
-            .commit();
+//            .commit();
 
         // lLinearLayout locations = (LinearLayout) findViewById(R.id.locations);
         // locations.setOnTouchListener(new OnSwipeTouchListener);
@@ -96,6 +102,13 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
         initLocalication();
         Fabric fabric = new Fabric.Builder(this).debuggable(true).kits(new Crashlytics()).build();
         Fabric.with(fabric);
+
+        Integer fragId = savedInstanceState != null ? savedInstanceState.getInt(FRAG_ID) : null;
+        Log.v(CLASS_TAG, "Restored orig frag id: " + fragId);
+        currentFragmentId = fragId == null ? 0 : fragId;
+        Log.v(CLASS_TAG, "Set final frag id: " + fragId);
+        switchFragment();
+
     }
 
     @Override
@@ -303,7 +316,7 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
     @Override
     protected void onResume() {
         super.onResume();
-
+        Log.v(CLASS_TAG, "onResume");
         if (locationProvider != null) {
             locationService.requestLocationUpdates(locationProvider,
                 AppConstants.MIN_TIME,
@@ -317,11 +330,18 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
     @Override
     protected void onPause() {
         super.onPause();
+        Log.v(CLASS_TAG, "onPause");
         if (locationServicesActivated) {
             locationService.removeUpdates(locationCallback);
         }
     }
 
+    @Override
+    protected void onDestroy() {
+        super.onDestroy();
+        Log.v(CLASS_TAG, "onDestroy");
+    }
+
     @Override
     public void onActivityResult(int requestCode, int resultCode, Intent data) {
 
@@ -339,4 +359,14 @@ public class MainActivity extends ActionBarActivity implements GestureDetector.O
                 super.onActivityResult(requestCode, resultCode, data);
         }
     }
+
+
+    @Override
+    protected void onSaveInstanceState(Bundle outState) {
+        Log.v(CLASS_TAG, "1 Saving current fragment id: " + currentFragmentId);
+        super.onSaveInstanceState(outState);
+        outState.putSerializable(FRAG_ID, currentFragmentId);
+        Log.v(CLASS_TAG, "2 Saving current fragment id: " + currentFragmentId);
+    }
+
 }

app/src/main/java/pl/tpolgrabia/urbanexplorer/fragments/HomeFragment.java

@@ -4,13 +4,13 @@ import android.content.Context;
 import android.location.Location;
 import android.location.LocationManager;
 import android.os.Bundle;
+import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
 import android.util.Log;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 import android.widget.*;
-import com.androidquery.AQuery;
 import pl.tpolgrabia.urbanexplorer.MainActivity;
 import pl.tpolgrabia.urbanexplorer.R;
 import pl.tpolgrabia.urbanexplorer.callbacks.PanoramioResponseCallback;
@@ -33,15 +33,14 @@ public class HomeFragment extends Fragment  {
 
     private static final int PANORAMIA_BULK_DATA_SIZE = 10;
     private LocationManager locationService;
-    private AQuery aq;
     private boolean initialized = false;
 
     private View inflatedView;
-    private Long pageId = 1L;
+    private Long pageId;
-    private Semaphore loading = new Semaphore(1, true);
+    private Semaphore loading;
-    private List<PanoramioImageInfo> photos = new ArrayList<>();
+    private List<PanoramioImageInfo> photos;
     private String locationProvider;
-    private boolean noMorePhotos = false;
+    private boolean noMorePhotos;
 
     public HomeFragment() {
         // Required empty public constructor
@@ -50,7 +49,21 @@ public class HomeFragment extends Fragment  {
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
-        aq = new AQuery(getActivity());
+        Log.v(CLASS_TAG, "onCreate");
+        pageId = 1L;
+        loading = new Semaphore(1, true);
+        photos = new ArrayList<>();
+        noMorePhotos = false;
+
+    }
+
+    @Override
+    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
+        super.onActivityCreated(savedInstanceState);
+        initLocationCallback();
+    }
+
+    private void initLocationCallback() {
         MainActivity mainActivity = ((MainActivity) getActivity());
         mainActivity.getLocationCallback()
             .addCallback(new StandardLocationListenerCallback() {
@@ -66,7 +79,6 @@ public class HomeFragment extends Fragment  {
                     }
                 }
             });
-
     }
 
     private Double safeParseDouble(CharSequence text) {
@@ -273,6 +285,7 @@ public class HomeFragment extends Fragment  {
     @Override
     public void onResume() {
         super.onResume();
+        Log.v(CLASS_TAG, "onResume");
         locationProvider = LocationUtils.getDefaultLocation(getActivity());
         updateLocationInfo();
     }
@@ -292,4 +305,24 @@ public class HomeFragment extends Fragment  {
             locationInfo.setText("Location: " + currLocation.getLatitude() + "," + currLocation.getLongitude());
         }
     }
+
+    @Override
+    public void onPause() {
+        super.onPause();
+        Log.v(CLASS_TAG, "onPause");
+    }
+
+    @Override
+    public void onDestroy() {
+        super.onDestroy();
+        Log.v(CLASS_TAG, "onDestroy");
+    }
+
+    @Override
+    public void onSaveInstanceState(Bundle outState) {
+        super.onSaveInstanceState(outState);
+
+        Log.v(CLASS_TAG, "Saving state");
+    }
+
 }

app/src/main/java/pl/tpolgrabia/urbanexplorer/fragments/WikiLocationsFragment.java

@@ -72,6 +72,13 @@ public class WikiLocationsFragment extends Fragment {
             @Override
             public void onClick(View v) {
                 final Location location = locationService.getLastKnownLocation(LocationUtils.getDefaultLocation(getActivity()));
+
+                if (location == null) {
+                    Log.i(CLASS_TAG, "Sorry, location is still not available");
+                    Toast.makeText(getActivity(), "Sorry, location is still not available", Toast.LENGTH_SHORT).show();
+                    return;
+                }
+
                 Editable search_limit = ((EditText) inflatedView.findViewById(R.id.wiki_search_limit)).getText();
                 Editable radius_limit = ((EditText) inflatedView.findViewById(R.id.wiki_search_radius)).getText();