Fixed NullPointer exceptions when cleaning notifications and courses on

preferences change

SWADroid/res/xml/preferences.xml

@@ -66,6 +66,7 @@
         <Preference
             android:defaultValue=""
             android:summary="@string/author_preferences"
+            android:key="aboutPref"
             android:title="@string/organization_preferences" />
     </PreferenceCategory>
 

SWADroid/src/es/ugr/swad/swadroid/Preferences.java

@@ -36,8 +36,8 @@ import android.preference.Preference.OnPreferenceChangeListener;
 import android.preference.Preference.OnPreferenceClickListener;
 import android.preference.PreferenceActivity;
 import android.preference.PreferenceManager;
-import es.ugr.swad.swadroid.modules.Courses;
-import es.ugr.swad.swadroid.modules.notifications.Notifications;
+import android.util.Log;
+import es.ugr.swad.swadroid.model.DataBaseHelper;
 import es.ugr.swad.swadroid.utils.Base64;
 
 /**
@@ -53,6 +53,10 @@ public class Preferences extends PreferenceActivity implements OnPreferenceChang
 	 * User identifier.
 	 */
 	private String userID;
+	/**
+	 * Database Helper.
+	 */
+	private static DataBaseHelper dbHelper; 
 	/**
 	 * User identifier preference name.
 	 */
@@ -316,6 +320,16 @@ public class Preferences extends PreferenceActivity implements OnPreferenceChang
 		userIDPref.setSummary(prefs.getString(USERIDPREF, ""));
 		userPasswordPref.setSummary(stars);
 	}
+	
+	/**
+	 * Deletes notifications and courses data from database
+	 */
+	private void cleanDatabase() {
+		dbHelper.emptyTable(Global.DB_TABLE_NOTIFICATIONS);
+		dbHelper.emptyTable(Global.DB_TABLE_COURSES);
+		setLastCourseSelected(0);
+		Global.setDbCleaned(true);
+	}
 
 	/**
 	 * Initializes preferences of activity.
@@ -342,6 +356,17 @@ public class Preferences extends PreferenceActivity implements OnPreferenceChang
 		//Restore preferences
 		addPreferencesFromResource(R.xml.preferences);
 		prefs = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
+		
+		//Initialize database
+		try {
+			dbHelper = new DataBaseHelper(this);
+		} catch (Exception ex) {
+			Log.e(ex.getClass().getSimpleName(), ex.getMessage());
+			ex.printStackTrace();
+			
+			//Send exception details to Bugsense
+			BugSenseHandler.sendException(ex);
+		}
 
 		userID = prefs.getString(USERIDPREF, "");
 		userPassword = prefs.getString(USERPASSWORDPREF, "");
@@ -507,14 +532,11 @@ public class Preferences extends PreferenceActivity implements OnPreferenceChang
 	 */
 	public boolean onPreferenceChange(Preference preference, Object newValue) {
 		String key = preference.getKey();
-		Notifications n = new Notifications();
-		Courses c = new Courses();
 
 		//If preferences have changed, logout and save new preferences
 		if (USERIDPREF.equals(key) || USERPASSWORDPREF.equals(key)) {
 			Global.setLogged(false);
-			n.clearNotifications(this);
-			c.clearCourses(this);
+			cleanDatabase();
 			Global.setPreferencesChanged();
 			editor.commit();
 		}
@@ -529,9 +551,8 @@ public class Preferences extends PreferenceActivity implements OnPreferenceChang
 
 		if (SERVERPREF.equals(key)) {
 			Global.setLogged(false);
-			n.clearNotifications(this);
-			c.clearCourses(this);
-			Global.setPreferencesChanged();			
+			cleanDatabase();
+			Global.setPreferencesChanged();
 			editor.commit();
 		}
 

SWADroid/src/es/ugr/swad/swadroid/gui/MenuActivity.java

@@ -92,7 +92,7 @@ public class MenuActivity extends Activity {
 	}
 
 	/**
-	 * Deletes notifications and tests data from database
+	 * Deletes all data from database
 	 */
 	protected void cleanDatabase() {
 		dbHelper.cleanTables();

SWADroid/src/es/ugr/swad/swadroid/gui/MenuExpandableListActivity.java

@@ -93,7 +93,7 @@ public class MenuExpandableListActivity extends ExpandableListActivity {
 	}
 
 	/**
-	 * Deletes notifications and tests data from database
+	 * Deletes all data from database
 	 */
 	protected void cleanDatabase() {
 		dbHelper.cleanTables();