Updated the empty list message with more contextual information---this time around server failures and errors.

app/src/main/java/com/example/android/sunshine/app/ForecastFragment.java

@@ -16,9 +16,11 @@
 package com.example.android.sunshine.app;
 
 import android.content.Intent;
+import android.content.SharedPreferences;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.LoaderManager;
 import android.support.v4.content.CursorLoader;
@@ -40,7 +42,7 @@ import com.example.android.sunshine.app.sync.SunshineSyncAdapter;
 /**
  * Encapsulates fetching the forecast and displaying it as a {@link ListView} layout.
  */
-public class ForecastFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor> {
+public class ForecastFragment extends Fragment implements LoaderManager.LoaderCallbacks<Cursor>, SharedPreferences.OnSharedPreferenceChangeListener {
     public static final String LOG_TAG = ForecastFragment.class.getSimpleName();
     private ForecastAdapter mForecastAdapter;
 
@@ -105,6 +107,20 @@ public class ForecastFragment extends Fragment implements LoaderManager.LoaderCa
         setHasOptionsMenu(true);
     }
 
+    @Override
+    public void onResume() {
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
+        sp.registerOnSharedPreferenceChangeListener(this);
+        super.onResume();
+    }
+
+    @Override
+    public void onPause() {
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getActivity());
+        sp.unregisterOnSharedPreferenceChangeListener(this);
+        super.onPause();
+    }
+
     @Override
     public void onCreateOptionsMenu(Menu menu, MenuInflater inflater) {
         inflater.inflate(R.menu.forecastfragment, menu);
@@ -281,11 +297,29 @@ public class ForecastFragment extends Fragment implements LoaderManager.LoaderCa
             if ( null != tv ) {
                 // if cursor is empty, why? do we have an invalid location
                 int message = R.string.empty_forecast_list;
-                if (!Utility.isNetworkAvailable(getActivity()) ) {
+                @SunshineSyncAdapter.LocationStatus int location = Utility.getLocationStatus(getActivity());
-                    message = R.string.empty_forecast_list_no_network;
+                switch (location) {
+                    case SunshineSyncAdapter.LOCATION_STATUS_SERVER_DOWN:
+                        message = R.string.empty_forecast_list_server_down;
+                        break;
+                    case SunshineSyncAdapter.LOCATION_STATUS_SERVER_INVALID:
+                        message = R.string.empty_forecast_list_server_error;
+                        break;
+                    default:
+                        if (!Utility.isNetworkAvailable(getActivity()) ) {
+                            message = R.string.empty_forecast_list_no_network;
+                        }
                 }
                 tv.setText(message);
             }
         }
     }
+
+    @Override
+    public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) {
+        if ( key.equals(getString(R.string.pref_location_status_key)) ) {
+            updateEmptyView();
+        }
+    }
+
 }

app/src/main/java/com/example/android/sunshine/app/Utility.java

@@ -22,6 +22,8 @@ import android.net.NetworkInfo;
 import android.preference.PreferenceManager;
 import android.text.format.Time;
 
+import com.example.android.sunshine.app.sync.SunshineSyncAdapter;
+
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.Date;
@@ -253,7 +255,7 @@ public class Utility {
      * Returns true if the network is available or about to become available.
      *
      * @param c Context used to get the ConnectivityManager
-     * @return
+     * @return true if the network is available
      */
     static public boolean isNetworkAvailable(Context c) {
         ConnectivityManager cm =
@@ -263,4 +265,16 @@ public class Utility {
         return activeNetwork != null &&
                 activeNetwork.isConnectedOrConnecting();
     }
+
+    /**
+     *
+     * @param c Context used to get the SharedPreferences
+     * @return the location status integer type
+     */
+    @SuppressWarnings("ResourceType")
+    static public @SunshineSyncAdapter.LocationStatus
+    int getLocationStatus(Context c){
+        SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(c);
+        return sp.getInt(c.getString(R.string.pref_location_status_key), SunshineSyncAdapter.LOCATION_STATUS_UNKNOWN);
+    }
 }

app/src/main/res/values/strings.xml

@@ -115,6 +115,7 @@
     <!-- Empty Weather Database -->
     <string name="empty_forecast_list">No Weather Information Available</string>
     <string name="empty_forecast_list_no_network">No weather information available. The network is not available to fetch weather data.</string>
-
+    <string name="empty_forecast_list_server_down">No weather information available. The server is not returning data.</string>
+    <string name="empty_forecast_list_server_error">No weather information available. The server is not returning valid data. Please check for an updated version of Sunshine.</string>
 
 </resources>