rework databasehelper as a singleton

simplify offline interaction with the database

org.fox.ttrss/src/main/java/org/fox/ttrss/CommonActivity.java

@@ -31,8 +31,10 @@ public class CommonActivity extends ActionBarActivity {
     public static final int EXCERPT_MAX_LENGTH = 256;
     public static final int EXCERPT_MAX_QUERY_LENGTH = 2048;
 
-	private SQLiteDatabase m_readableDb;
+	private DatabaseHelper m_databaseHelper;
-	private SQLiteDatabase m_writableDb;
+
+	//private SQLiteDatabase m_readableDb;
+	//private SQLiteDatabase m_writableDb;
 
 	private boolean m_smallScreenMode = true;
 	private String m_theme;
@@ -57,6 +59,14 @@ public class CommonActivity extends ActionBarActivity {
 		m_smallScreenMode = smallScreen;
 	}
 
+	public DatabaseHelper getDatabaseHelper() {
+		return m_databaseHelper;
+	}
+
+	public SQLiteDatabase getDatabase() {
+		return m_databaseHelper.getWritableDatabase();
+	}
+
 	public boolean getUnreadOnly() {
 		return m_prefs.getBoolean("show_unread_only", true);
 	}
@@ -82,21 +92,6 @@ public class CommonActivity extends ActionBarActivity {
 		toast.show();
 	}
 
-	private void initDatabase() {
-		DatabaseHelper dh = new DatabaseHelper(getApplicationContext());
-		
-		m_writableDb = dh.getWritableDatabase();
-		m_readableDb = dh.getReadableDatabase();
-	}
-	
-	public synchronized SQLiteDatabase getReadableDb() {
-		return m_readableDb;
-	}
-
-	public synchronized SQLiteDatabase getWritableDb() {
-		return m_writableDb;
-	}
-
 	@Override
 	public void onResume() {
 		super.onResume();
@@ -113,13 +108,12 @@ public class CommonActivity extends ActionBarActivity {
 	@Override
 	public void onDestroy() {
 		super.onDestroy();
-
-		m_readableDb.close();
-		m_writableDb.close();
 	}
 
 	@Override
 	public void onCreate(Bundle savedInstanceState) {
+		m_databaseHelper = DatabaseHelper.getInstance(this);
+
 		m_prefs = PreferenceManager
 				.getDefaultSharedPreferences(getApplicationContext());
 
@@ -129,8 +123,6 @@ public class CommonActivity extends ActionBarActivity {
 			m_theme = m_prefs.getString("theme", CommonActivity.THEME_DEFAULT);
 		}
 
-		initDatabase();
-
 		super.onCreate(savedInstanceState);
 	}
 

org.fox.ttrss/src/main/java/org/fox/ttrss/OnlineActivity.java

@@ -14,7 +14,6 @@ import android.content.IntentFilter;
 import android.content.SharedPreferences;
 import android.content.pm.PackageInfo;
 import android.content.pm.PackageManager;
-import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
 import android.preference.PreferenceManager;
@@ -277,40 +276,6 @@ public class OnlineActivity extends CommonActivity {
 		}
 	}
 	
-	private boolean hasPendingOfflineData() {
-		try {
-			Cursor c = getReadableDb().query("articles",
-					new String[] { "COUNT(*)" }, "modified = 1", null, null, null,
-					null);
-			if (c.moveToFirst()) {
-				int modified = c.getInt(0);
-				c.close();
-	
-				return modified > 0;
-			}
-		} catch (IllegalStateException e) {
-			// db is closed? ugh
-		}
-
-		return false;
-	}
-
-	private boolean hasOfflineData() {
-		try {
-			Cursor c = getReadableDb().query("articles",
-					new String[] { "COUNT(*)" }, null, null, null, null, null);
-			if (c.moveToFirst()) {
-				int modified = c.getInt(0);
-				c.close();
-	
-				return modified > 0;
-			}
-		} catch (IllegalStateException e) {
-			// db is closed?
-		}
-
-		return false;
-	}
 
 	@Override
 	public void onPause() {
@@ -463,7 +428,7 @@ public class OnlineActivity extends CommonActivity {
 		startActivityForResult(intent, 0);
 		overridePendingTransition(0, 0);
 
-		if (hasPendingOfflineData())
+		if (getDatabaseHelper().hasPendingOfflineData())
 			syncOfflineData();
 		
 		finish();
@@ -1192,7 +1157,7 @@ public class OnlineActivity extends CommonActivity {
 		setSessionId(null);
 		initMenu();
 		
-		if (hasOfflineData()) {
+		if (getDatabaseHelper().hasOfflineData()) {
 
 			AlertDialog.Builder builder = new AlertDialog.Builder(
 					OnlineActivity.this)

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineActivity.java

@@ -207,10 +207,10 @@ public class OfflineActivity extends CommonActivity {
 			SQLiteStatement stmtSelectAll = null;
 			
 			if (isCat) {
-				stmtSelectAll = getWritableDb().compileStatement(
+				stmtSelectAll = getDatabase().compileStatement(
 						"UPDATE articles SET selected = 1 WHERE feed_id IN (SELECT "+BaseColumns._ID+" FROM feeds WHERE cat_id = ?)");
 			} else {
-				stmtSelectAll = getWritableDb().compileStatement(
+				stmtSelectAll = getDatabase().compileStatement(
 								"UPDATE articles SET selected = 1 WHERE feed_id = ?");
 			}
 			
@@ -224,10 +224,10 @@ public class OfflineActivity extends CommonActivity {
 			SQLiteStatement stmtSelectUnread = null;
 			
 			if (isCat) {
-				stmtSelectUnread = getWritableDb().compileStatement(
+				stmtSelectUnread = getDatabase().compileStatement(
 						"UPDATE articles SET selected = 1 WHERE feed_id IN (SELECT "+BaseColumns._ID+" FROM feeds WHERE cat_id = ?) AND unread = 1");
 			} else {
-				stmtSelectUnread = getWritableDb().compileStatement(
+				stmtSelectUnread = getDatabase().compileStatement(
 								"UPDATE articles SET selected = 1 WHERE feed_id = ? AND unread = 1");
 			}
 			
@@ -455,7 +455,7 @@ public class OfflineActivity extends CommonActivity {
 			if (oap != null) {
 				int articleId = oap.getSelectedArticleId();
 				
-				SQLiteStatement stmt = getWritableDb().compileStatement(
+				SQLiteStatement stmt = getDatabase().compileStatement(
 						"UPDATE articles SET modified = 1, marked = NOT marked WHERE "
 								+ BaseColumns._ID + " = ?");
 				stmt.bindLong(1, articleId);
@@ -470,7 +470,7 @@ public class OfflineActivity extends CommonActivity {
 			return true; */
 		case R.id.selection_toggle_unread:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = getWritableDb()
+				SQLiteStatement stmt = getDatabase()
 						.compileStatement(
 								"UPDATE articles SET modified = 1, unread = NOT unread WHERE selected = 1");
 				stmt.execute();
@@ -481,7 +481,7 @@ public class OfflineActivity extends CommonActivity {
 			return true;
 		case R.id.selection_toggle_marked:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = getWritableDb()
+				SQLiteStatement stmt = getDatabase()
 						.compileStatement(
 								"UPDATE articles SET modified = 1, marked = NOT marked WHERE selected = 1");
 				stmt.execute();
@@ -492,7 +492,7 @@ public class OfflineActivity extends CommonActivity {
 			return true;
 		case R.id.selection_toggle_published:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = getWritableDb()
+				SQLiteStatement stmt = getDatabase()
 						.compileStatement(
 								"UPDATE articles SET modified = 1, published = NOT published WHERE selected = 1");
 				stmt.execute();
@@ -505,7 +505,7 @@ public class OfflineActivity extends CommonActivity {
 			if (oap != null) {
 				int articleId = oap.getSelectedArticleId();
 				
-				SQLiteStatement stmt = getWritableDb().compileStatement(
+				SQLiteStatement stmt = getDatabase().compileStatement(
 						"UPDATE articles SET modified = 1, published = NOT published WHERE "
 								+ BaseColumns._ID + " = ?");
 				stmt.bindLong(1, articleId);
@@ -524,12 +524,12 @@ public class OfflineActivity extends CommonActivity {
 				SQLiteStatement stmt = null;
 				
 				if (isCat) {
-					stmt = getWritableDb().compileStatement(
+					stmt = getDatabase().compileStatement(
 							"UPDATE articles SET modified = 1, unread = 0 WHERE " +
 							"updated >= (SELECT updated FROM articles WHERE " + BaseColumns._ID + " = ?) " +
 							"AND feed_id IN (SELECT "+BaseColumns._ID+" FROM feeds WHERE cat_id = ?)");						
 				} else {
-					stmt = getWritableDb().compileStatement(
+					stmt = getDatabase().compileStatement(
 							"UPDATE articles SET modified = 1, unread = 0 WHERE " +
 							"updated >= (SELECT updated FROM articles WHERE " + BaseColumns._ID + " = ?) " +
 							"AND feed_id = ?");						
@@ -614,9 +614,9 @@ public class OfflineActivity extends CommonActivity {
 	}
 	
 	protected Cursor getArticleById(int articleId) {
-		Cursor c = getReadableDb().query("articles", null,
+		Cursor c = getDatabase().query("articles", null,
 				BaseColumns._ID + "=?",
-				new String[] { String.valueOf(articleId) }, null, null, null);
+				new String[]{String.valueOf(articleId)}, null, null, null);
 
 		c.moveToFirst();
 
@@ -659,9 +659,9 @@ public class OfflineActivity extends CommonActivity {
 	}
 	
 	protected Cursor getFeedById(int feedId) {
-		Cursor c = getReadableDb().query("feeds", null,
+		Cursor c = getDatabase().query("feeds", null,
 				BaseColumns._ID + "=?",
-				new String[] { String.valueOf(feedId) }, null, null, null);
+				new String[]{String.valueOf(feedId)}, null, null, null);
 
 		c.moveToFirst();
 
@@ -669,9 +669,9 @@ public class OfflineActivity extends CommonActivity {
 	}
 
 	protected Cursor getCatById(int catId) {
-		Cursor c = getReadableDb().query("categories", null,
+		Cursor c = getDatabase().query("categories", null,
 				BaseColumns._ID + "=?",
-				new String[] { String.valueOf(catId) }, null, null, null);
+				new String[]{String.valueOf(catId)}, null, null, null);
 
 		c.moveToFirst();
 
@@ -715,8 +715,8 @@ public class OfflineActivity extends CommonActivity {
 	}
 
 	protected int getSelectedArticleCount() {
-		Cursor c = getReadableDb().query("articles",
+		Cursor c = getDatabase().query("articles",
-				new String[] { "COUNT(*)" }, "selected = 1", null, null, null,
+				new String[]{"COUNT(*)"}, "selected = 1", null, null, null,
 				null);
 		c.moveToFirst();
 		int selected = c.getInt(0);
@@ -730,12 +730,12 @@ public class OfflineActivity extends CommonActivity {
 		Cursor c;
 		
 		if (isCat) {
-			c = getReadableDb().query("articles",
+			c = getDatabase().query("articles",
 				new String[] { "COUNT(*)" }, "unread = 1 AND feed_id IN (SELECT "+BaseColumns._ID+" FROM feeds WHERE cat_id = ?)", 
 				new String[] { String.valueOf(feedId) },
 				null, null, null);
 		} else {
-			c = getReadableDb().query("articles",
+			c = getDatabase().query("articles",
 				new String[] { "COUNT(*)" }, "unread = 1 AND feed_id = ?", 
 				new String[] { String.valueOf(feedId) }, 
 				null, null, null);
@@ -749,7 +749,7 @@ public class OfflineActivity extends CommonActivity {
 	}
 	
 	protected void deselectAllArticles() {
-		getWritableDb().execSQL("UPDATE articles SET selected = 0 ");
+		getDatabase().execSQL("UPDATE articles SET selected = 0 ");
 		refresh();
 	}
 
@@ -780,14 +780,14 @@ public class OfflineActivity extends CommonActivity {
 
 	public void catchupFeed(int feedId, boolean isCat) {
 		if (isCat) {
-			SQLiteStatement stmt = getWritableDb().compileStatement(
+			SQLiteStatement stmt = getDatabase().compileStatement(
-					"UPDATE articles SET modified = 1, unread = 0 WHERE feed_id IN (SELECT "+
+					"UPDATE articles SET modified = 1, unread = 0 WHERE feed_id IN (SELECT " +
-						BaseColumns._ID+" FROM feeds WHERE cat_id = ?)");
+							BaseColumns._ID + " FROM feeds WHERE cat_id = ?)");
 			stmt.bindLong(1, feedId);
 			stmt.execute();
 			stmt.close();
 		} else {
-			SQLiteStatement stmt = getWritableDb().compileStatement(
+			SQLiteStatement stmt = getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, unread = 0 WHERE feed_id = ?");
 			stmt.bindLong(1, feedId);
 			stmt.execute();

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineArticleFragment.java

@@ -126,7 +126,7 @@ public class OfflineArticleFragment extends Fragment {
 		
 		View view = inflater.inflate(R.layout.fragment_article, container, false);
 
-		m_cursor = m_activity.getReadableDb().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
+		m_cursor = m_activity.getDatabase().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
 				new String[] { "articles.*", "feeds.title AS feed_title" }, "articles." + BaseColumns._ID + "=?", 
 				new String[] { String.valueOf(m_articleId) }, null, null, null);
 

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineArticlePager.java

@@ -66,11 +66,11 @@ public class OfflineArticlePager extends Fragment {
 		String orderBy = (m_prefs.getBoolean("offline_oldest_first", false)) ? "updated" : "updated DESC";
 		
 		if (m_searchQuery == null || m_searchQuery.equals("")) {
-			return m_activity.getReadableDb().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
+			return m_activity.getDatabase().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
 					new String[] { "articles."+BaseColumns._ID, "feeds.title AS feed_title" }, feedClause, 
 					new String[] { String.valueOf(m_feedId) }, null, null, orderBy);
 		} else {
-			return m_activity.getReadableDb().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
+			return m_activity.getDatabase().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
 					new String[] { "articles."+BaseColumns._ID },
 					feedClause + " AND (articles.title LIKE '%' || ? || '%' OR content LIKE '%' || ? || '%')", 
 					new String[] { String.valueOf(m_feedId), m_searchQuery, m_searchQuery }, null, null, orderBy);

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineDetailActivity.java

@@ -145,7 +145,7 @@ public class OfflineDetailActivity extends OfflineActivity implements OfflineHea
 	public void onArticleSelected(int articleId, boolean open) {
 		
 		if (!open) {
-			SQLiteStatement stmt = getWritableDb().compileStatement(
+			SQLiteStatement stmt = getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, unread = 0 " + "WHERE " + BaseColumns._ID
 							+ " = ?");
 		

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineDownloadService.java

@@ -180,7 +180,7 @@ public class OfflineDownloadService extends Service {
 	}
 	
 	private void initDatabase() {
-		DatabaseHelper dh = new DatabaseHelper(getApplicationContext());
+		DatabaseHelper dh = DatabaseHelper.getInstance(this);
 		m_writableDb = dh.getWritableDatabase();
 		m_readableDb = dh.getReadableDatabase();
 	}

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineFeedCategoriesFragment.java

@@ -61,7 +61,7 @@ public class OfflineFeedCategoriesFragment extends BaseFeedlistFragment implemen
 		
 		String order = m_prefs.getBoolean("sort_feeds_by_unread", false) ? "unread DESC, title" : "title";
 		
-		return m_activity.getReadableDb().query("cats_unread", 
+		return m_activity.getDatabase().query("cats_unread", 
 				null, unreadOnly, null, null, null, order);
 	}
 	

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineFeedsFragment.java

@@ -99,10 +99,10 @@ public class OfflineFeedsFragment extends BaseFeedlistFragment implements OnItem
 		String order = m_prefs.getBoolean("sort_feeds_by_unread", false) ? "unread DESC, title" : "title";
 		
 		if (m_catId != -1) {
-			return m_activity.getReadableDb().query("feeds_unread", 
+			return m_activity.getDatabase().query("feeds_unread", 
 					null, unreadOnly + " AND cat_id = ?",  new String[] { String.valueOf(m_catId) }, null, null, order);
 		} else {		
-			return m_activity.getReadableDb().query("feeds_unread", 
+			return m_activity.getDatabase().query("feeds_unread", 
 				null, unreadOnly, null, null, null, order);
 		}
 	}

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineHeadlinesFragment.java

@@ -87,7 +87,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 	}
 	
 	public int getSelectedArticleCount() {
-		Cursor c = m_activity.getReadableDb().query("articles", 
+		Cursor c = m_activity.getDatabase().query("articles", 
 				new String[] { "COUNT(*)" }, "selected = 1", null, null, null, null);
 		c.moveToFirst();
 		int selected = c.getInt(0);
@@ -116,7 +116,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			return true;
 		case R.id.selection_toggle_marked:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = m_activity.getWritableDb()
+				SQLiteStatement stmt = m_activity.getDatabase()
 				.compileStatement(
 						"UPDATE articles SET modified = 1, marked = NOT marked WHERE selected = 1");
 				stmt.execute();
@@ -124,7 +124,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			} else {
 				int articleId = getArticleIdAtPosition(info.position);
 				
-				SQLiteStatement stmt = m_activity.getWritableDb().compileStatement(
+				SQLiteStatement stmt = m_activity.getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, marked = NOT marked WHERE "
 							+ BaseColumns._ID + " = ?");
 				stmt.bindLong(1, articleId);
@@ -135,7 +135,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			return true;
 		case R.id.selection_toggle_published:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = m_activity.getWritableDb()
+				SQLiteStatement stmt = m_activity.getDatabase()
 				.compileStatement(
 						"UPDATE articles SET modified = 1, published = NOT published WHERE selected = 1");
 				stmt.execute();
@@ -143,7 +143,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			} else {
 				int articleId = getArticleIdAtPosition(info.position);
 				
-				SQLiteStatement stmt = m_activity.getWritableDb().compileStatement(
+				SQLiteStatement stmt = m_activity.getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, published = NOT published WHERE "
 							+ BaseColumns._ID + " = ?");
 				stmt.bindLong(1, articleId);
@@ -154,7 +154,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			return true;
 		case R.id.selection_toggle_unread:
 			if (getSelectedArticleCount() > 0) {
-				SQLiteStatement stmt = m_activity.getWritableDb()
+				SQLiteStatement stmt = m_activity.getDatabase()
 				.compileStatement(
 						"UPDATE articles SET modified = 1, unread = NOT unread WHERE selected = 1");
 				stmt.execute();
@@ -162,7 +162,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			} else {
 				int articleId = getArticleIdAtPosition(info.position);
 				
-				SQLiteStatement stmt = m_activity.getWritableDb().compileStatement(
+				SQLiteStatement stmt = m_activity.getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, unread = NOT unread WHERE "
 							+ BaseColumns._ID + " = ?");
 				stmt.bindLong(1, articleId);
@@ -186,12 +186,12 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 				String updatedOperator = (m_prefs.getBoolean("offline_oldest_first", false)) ? "<" : ">";
 				
 				if (m_feedIsCat) {
-					stmt = m_activity.getWritableDb().compileStatement(
+					stmt = m_activity.getDatabase().compileStatement(
 							"UPDATE articles SET modified = 1, unread = 0 WHERE " +
 							"updated "+updatedOperator+" (SELECT updated FROM articles WHERE " + BaseColumns._ID + " = ?) " +
 							"AND unread = 1 AND feed_id IN (SELECT "+BaseColumns._ID+" FROM feeds WHERE cat_id = ?)");						
 				} else {
-					stmt = m_activity.getWritableDb().compileStatement(
+					stmt = m_activity.getDatabase().compileStatement(
 							"UPDATE articles SET modified = 1, unread = 0 WHERE " +
 							"updated "+updatedOperator+" (SELECT updated FROM articles WHERE " + BaseColumns._ID + " = ?) " +
 							"AND unread = 1 AND feed_id = ?");						
@@ -285,7 +285,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 			m_feedIsCat = savedInstanceState.getBoolean("feedIsCat");
             m_compactLayoutMode = savedInstanceState.getBoolean("compactLayoutMode");
 		} else {
-			m_activity.getWritableDb().execSQL("UPDATE articles SET selected = 0 ");
+			m_activity.getDatabase().execSQL("UPDATE articles SET selected = 0 ");
 		}
 
         if ("HL_COMPACT".equals(m_prefs.getString("headline_mode", "HL_DEFAULT")))
@@ -365,11 +365,11 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 		String orderBy = (m_prefs.getBoolean("offline_oldest_first", false)) ? "updated" : "updated DESC";
 		
 		if (m_searchQuery == null || m_searchQuery.equals("")) {
-			return m_activity.getReadableDb().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
+			return m_activity.getDatabase().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
 					new String[] { "articles.*", "feeds.title AS feed_title" }, feedClause, 
 					new String[] { String.valueOf(m_feedId) }, null, null, orderBy);
 		} else {
-			return m_activity.getReadableDb().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
+			return m_activity.getDatabase().query("articles LEFT JOIN feeds ON (feed_id = feeds."+BaseColumns._ID+")", 
 					new String[] { "articles.*", "feeds.title AS feed_title" },
 					feedClause + " AND (articles.title LIKE '%' || ? || '%' OR content LIKE '%' || ? || '%')", 
 					new String[] { String.valueOf(m_feedId), m_searchQuery, m_searchQuery }, null, null, orderBy);
@@ -596,7 +596,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
                     public void onClick(View view) {
                         Log.d(TAG, "textImage : onclicked");
 
-                        SQLiteStatement stmtUpdate = m_activity.getWritableDb().compileStatement("UPDATE articles SET selected = NOT selected " +
+                        SQLiteStatement stmtUpdate = m_activity.getDatabase().compileStatement("UPDATE articles SET selected = NOT selected " +
                                 "WHERE " + BaseColumns._ID + " = ?");
 
                         stmtUpdate.bindLong(1, articleId);
@@ -651,7 +651,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 
 					@Override
 					public void onClick(View v) {
-						SQLiteStatement stmtUpdate = m_activity.getWritableDb().compileStatement("UPDATE articles SET modified = 1, marked = NOT marked " +
+						SQLiteStatement stmtUpdate = m_activity.getDatabase().compileStatement("UPDATE articles SET modified = 1, marked = NOT marked " +
 								"WHERE " + BaseColumns._ID + " = ?");
 
 						stmtUpdate.bindLong(1, articleId);
@@ -673,7 +673,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
 
                     @Override
                     public void onClick(View v) {
-                        SQLiteStatement stmtUpdate = m_activity.getWritableDb().compileStatement("UPDATE articles SET modified = 1, published = NOT published " +
+                        SQLiteStatement stmtUpdate = m_activity.getDatabase().compileStatement("UPDATE articles SET modified = 1, published = NOT published " +
                                 "WHERE " + BaseColumns._ID + " = ?");
 
                         stmtUpdate.bindLong(1, articleId);
@@ -734,7 +734,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
                     public void onClick(View view) {
                         CheckBox cb = (CheckBox) view;
 
-                        SQLiteStatement stmtUpdate = m_activity.getWritableDb().compileStatement("UPDATE articles SET selected = ? " +
+                        SQLiteStatement stmtUpdate = m_activity.getDatabase().compileStatement("UPDATE articles SET selected = ? " +
                                 "WHERE " + BaseColumns._ID + " = ?");
 
                         stmtUpdate.bindLong(1, cb.isChecked() ? 1 : 0);
@@ -897,7 +897,7 @@ public class OfflineHeadlinesFragment extends Fragment implements OnItemClickLis
         if (scrollState == SCROLL_STATE_IDLE && m_prefs.getBoolean("headlines_mark_read_scroll", false)) {
             if (!m_readArticleIds.isEmpty()) {
 
-                SQLiteStatement stmt = m_activity.getWritableDb().compileStatement(
+                SQLiteStatement stmt = m_activity.getDatabase().compileStatement(
                         "UPDATE articles SET modified = 1, unread = 0 " + "WHERE " + BaseColumns._ID
                                 + " = ?");
 

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineMasterActivity.java

@@ -321,7 +321,7 @@ public class OfflineMasterActivity extends OfflineActivity implements OfflineHea
 	public void onArticleSelected(int articleId, boolean open) {
 		
 		if (!open) {
-			SQLiteStatement stmt = getWritableDb().compileStatement(
+			SQLiteStatement stmt = getDatabase().compileStatement(
 					"UPDATE articles SET modified = 1, unread = 0 " + "WHERE " + BaseColumns._ID
 							+ " = ?");
 	

org.fox.ttrss/src/main/java/org/fox/ttrss/offline/OfflineUploadService.java

@@ -89,7 +89,7 @@ public class OfflineUploadService extends IntentService {
 	}
 
 	private void initDatabase() {
-		DatabaseHelper dh = new DatabaseHelper(getApplicationContext());
+		DatabaseHelper dh = DatabaseHelper.getInstance(this);
 		m_writableDb = dh.getWritableDatabase();
 		m_readableDb = dh.getReadableDatabase();
 	}

org.fox.ttrss/src/main/java/org/fox/ttrss/util/DatabaseHelper.java

@@ -1,5 +1,7 @@
 package org.fox.ttrss.util;
+
 import android.content.Context;
+import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteOpenHelper;
 import android.provider.BaseColumns;
@@ -11,9 +13,21 @@ public class DatabaseHelper extends SQLiteOpenHelper {
 	private final String TAG = this.getClass().getSimpleName();
 	public static final String DATABASE_NAME = "OfflineStorage.db";
 	public static final int DATABASE_VERSION = 4;
+	private static DatabaseHelper m_instance;
+	private Context m_context;
 
-	public DatabaseHelper(Context context) {
+	private DatabaseHelper(Context context) {
 		super(context, DATABASE_NAME, null, DATABASE_VERSION);
+		m_context = context;
+	}
+
+	public static synchronized DatabaseHelper getInstance(Context context) {
+
+		if (m_instance == null) {
+			m_instance = new DatabaseHelper(context.getApplicationContext());
+		}
+
+		return m_instance;
 	}
 
 	@Override
@@ -86,4 +100,39 @@ public class DatabaseHelper extends SQLiteOpenHelper {
 		onCreate(db);
 	}
 
+	public boolean hasPendingOfflineData() {
+		try {
+			Cursor c = getReadableDatabase().query("articles",
+					new String[] { "COUNT(*)" }, "modified = 1", null, null, null,
+					null);
+			if (c.moveToFirst()) {
+				int modified = c.getInt(0);
+				c.close();
+
+				return modified > 0;
+			}
+		} catch (IllegalStateException e) {
+			// db is closed? ugh
+		}
+
+		return false;
+	}
+
+	public boolean hasOfflineData() {
+		try {
+			Cursor c = getReadableDatabase().query("articles",
+					new String[] { "COUNT(*)" }, null, null, null, null, null);
+			if (c.moveToFirst()) {
+				int modified = c.getInt(0);
+				c.close();
+
+				return modified > 0;
+			}
+		} catch (IllegalStateException e) {
+			// db is closed?
+		}
+
+		return false;
+	}
+
 }