support loading more headlines from main menu

res/menu/main_menu.xml

@@ -20,7 +20,12 @@
           android:title="@string/close_article" 
           android:showAsAction="ifRoom|withText"/>
         
-          
+     <item android:id="@+id/load_more_articles"
+     	  android:visible="false"
+          android:icon="@android:drawable/ic_menu_more"
+          android:title="@string/load_more_articles" 
+          android:showAsAction="ifRoom|withText"/>
+     
      <item android:id="@+id/update_feeds"
      	  android:enabled="false"
           android:icon="@android:drawable/ic_menu_rotate"

res/values/strings.xml

@@ -33,4 +33,5 @@
     <string name="share_article">Share article</string>
     <string name="could_not_decode_content">Could not decode content (UnsupportedEncodingException)</string>
     <string name="sort_feeds_by_unread">Sort feeds by unread count</string>
+    <string name="load_more_articles">More headlines...</string>
 </resources>

src/org/fox/ttrss/HeadlinesFragment.java

@@ -79,7 +79,7 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 		Log.d(TAG, "onCreateView, feed=" + m_feed);
 		
 		if (m_feed != null && (m_articles == null || m_articles.size() == 0)) 
-			refresh();
+			refresh(false);
 		else
 			view.findViewById(R.id.loading_container).setVisibility(View.GONE);
 
@@ -121,13 +121,26 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 		}
 	}
 
-	public void refresh() {
+	public void refresh(boolean append) {
 		HeadlinesRequest req = new HeadlinesRequest();
 		
 		req.setApi(m_prefs.getString("ttrss_url", null));
 		
 		final String sessionId = ((MainActivity)getActivity()).getSessionId();
-
+		int skip = 0;
+		
+		if (append) {
+			for (Article a : m_articles) {
+				if (a.unread) ++skip;
+			}
+			
+			if (skip == 0) skip = m_articles.size();
+		}
+		
+		final int fskip = skip;
+		
+		req.setOffset(skip);
+		
 		HashMap<String,String> map = new HashMap<String,String>() {
 			{
 				put("op", "getHeadlines");
@@ -137,6 +150,7 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 				put("limit", String.valueOf(30));
 				put("offset", String.valueOf(0));
 				put("view_mode", "adaptive");
+				put("skip", String.valueOf(fskip));
 			}			 
 		};
 
@@ -154,6 +168,7 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 	}
 
 	private class HeadlinesRequest extends ApiRequest {
+		int m_offset = 0;
 		
 		protected void onPostExecute(JsonElement result) {
 			if (result != null) {
@@ -172,12 +187,14 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 							
 							getActivity().runOnUiThread(new Runnable() {
 								public void run() {
-									m_articles.clear();
+									
+									if (m_offset == 0)
+										m_articles.clear();
 									
 									for (Article f : articles) 
 										m_articles.add(f);
 									
-									m_adapter.notifyDataSetInvalidated();
+									m_adapter.notifyDataSetChanged();
 									
 									showLoading(false);
 								}
@@ -199,6 +216,10 @@ public class HeadlinesFragment extends Fragment implements OnItemClickListener {
 			return;
 
 	    }
+
+		public void setOffset(int skip) {
+			m_offset = skip;			
+		}
 	}
 	
 	public void catchupArticle(final Article article) {

src/org/fox/ttrss/MainActivity.java

@@ -225,6 +225,9 @@ public class MainActivity extends FragmentActivity implements FeedsFragment.OnFe
 		case R.id.close_article:
 			closeArticle();
 			return true;
+		case R.id.load_more_articles:
+			viewFeed(m_activeFeed, true);
+			return true;
 		case R.id.share_article:
 			shareArticle(m_selectedArticle);
 			return true;
@@ -285,14 +288,17 @@ public class MainActivity extends FragmentActivity implements FeedsFragment.OnFe
 					m_menu.findItem(R.id.update_feeds).setEnabled(true);
 					m_menu.findItem(R.id.show_feeds).setEnabled(true);
 				}
-				
+
+				m_menu.findItem(R.id.load_more_articles).setVisible(m_activeFeed != null);
+
 			} else {
 				m_menu.findItem(R.id.login).setVisible(true);
 				
 				m_menu.findItem(R.id.logout).setVisible(false);
 				m_menu.findItem(R.id.close_article).setVisible(false);
 				m_menu.findItem(R.id.share_article).setVisible(false);
-				
+				m_menu.findItem(R.id.load_more_articles).setVisible(false);
+
 				m_menu.findItem(R.id.update_feeds).setEnabled(false);
 				m_menu.findItem(R.id.show_feeds).setEnabled(false);
 			}
@@ -377,21 +383,30 @@ public class MainActivity extends FragmentActivity implements FeedsFragment.OnFe
 	@Override
 	public void onFeedSelected(Feed feed) {
 		Log.d(TAG, "Selected feed: " + feed.toString());
-		viewFeed(feed);
+		viewFeed(feed, false);
 	}
 
 	public Article getSelectedArticle() {
 		return m_selectedArticle;
 	}
 	
-	public void viewFeed(Feed feed) {
+	public void viewFeed(Feed feed, boolean append) {
 		m_activeFeed = feed;
+	
+		initMainMenu();
 		
-		HeadlinesFragment hf = new HeadlinesFragment();
+		if (!append) {
+			HeadlinesFragment hf = new HeadlinesFragment();
 		
-		FragmentTransaction ft = getSupportFragmentManager().beginTransaction();			
+			FragmentTransaction ft = getSupportFragmentManager().beginTransaction();			
-		ft.replace(R.id.headlines_fragment, hf);
+			ft.replace(R.id.headlines_fragment, hf);
-		ft.commit();
+			ft.commit();
+		} else {
+			HeadlinesFragment hf = (HeadlinesFragment)getSupportFragmentManager().findFragmentById(R.id.headlines_fragment);
+			if (hf != null) {
+				hf.refresh(true);
+			}
+		}
 	}
 
 	public void openArticle(Article article) {