LAb 4 fertifg

AirKoality/app/src/main/java/at/fhj/airkoality/ui/activity/MainActivity.java

@@ -1,6 +1,8 @@
 package at.fhj.airkoality.ui.activity;
 
+import android.content.SharedPreferences;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.design.widget.BottomNavigationView;
@@ -21,10 +23,13 @@ public class MainActivity extends AppCompatActivity {
 
     private static final  String LOCATION_LIST = "location_list";
     private static final  String MAP = "map";
+    private static final  String FRAGMENT_PREF_KEY = "last_fragment";
 
 
     private BottomNavigationView bottomNavigationView;
 
+    private SharedPreferences sharedPreferences;
+
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -36,6 +41,9 @@ public class MainActivity extends AppCompatActivity {
 
         bottomNavigationView = findViewById(R.id.bnvMain);
 
+
+        sharedPreferences = PreferenceManager.getDefaultSharedPreferences(this);
+
         FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
         transaction.add(R.id.flFragmentContainer, locationListFragment);
         transaction.add(R.id.flFragmentContainer, mapFragment);
@@ -49,15 +57,22 @@ public class MainActivity extends AppCompatActivity {
                 switch (menuItem.getItemId()){
                     case R.id.action_location:
                         setSelectedFragment(LOCATION_LIST);
+                        sharedPreferences.edit()
+                                .putString(FRAGMENT_PREF_KEY, LOCATION_LIST)
+                                .commit();
+
                         break;
                     case R.id.action_map:
                         setSelectedFragment(MAP);
+                        sharedPreferences.edit()
+                                .putString(FRAGMENT_PREF_KEY, MAP)
+                                .commit();
                         break;
                 }
                 return false;
             }
         });
-        setSelectedFragment(LOCATION_LIST);
+        setSelectedFragment(sharedPreferences.getString("last_fragment", LOCATION_LIST));
 
     }
 

README.md

@@ -59,4 +59,6 @@ RecyclerView -> Items der View wiederverwendbar machen
 - unterschiedliche Möglichkeiten der Speicherung
   - local storage (im App Verzeichnis)
   - external storage
-  - 
+  - shared preferences (key - value pairs, internes XML file)
+  - SQLite -> single file database
+- Permissions beim Speichern beachten