infite scrolling

src/eu/siacs/conversations/persistance/DatabaseBackend.java

@@ -129,13 +129,25 @@ public class DatabaseBackend extends SQLiteOpenHelper {
 		return list;
 	}
 	
-	public List<Message> getMessages(Conversation conversation, int limit) {
+	public List<Message> getMessages(Conversation conversations, int limit) {
+		return getMessages(conversations, limit,-1);
+	}
+
+	public List<Message> getMessages(Conversation conversation, int limit, long timestamp) {
 		List<Message> list = new CopyOnWriteArrayList<Message>();
 		SQLiteDatabase db = this.getReadableDatabase();
+		Cursor cursor;
+		if (timestamp==-1) {
 			String[] selectionArgs = { conversation.getUuid() };
-		Cursor cursor = db.query(Message.TABLENAME, null, Message.CONVERSATION
+			cursor = db.query(Message.TABLENAME, null, Message.CONVERSATION
 					+ "=?", selectionArgs, null, null, Message.TIME_SENT + " DESC",
 					String.valueOf(limit));
+		} else {
+			String[] selectionArgs = { conversation.getUuid() , ""+timestamp};
+			cursor = db.query(Message.TABLENAME, null, Message.CONVERSATION
+					+ "=? and "+Message.TIME_SENT+"<?", selectionArgs, null, null, Message.TIME_SENT + " DESC",
+					String.valueOf(limit));
+		}
 		if (cursor.getCount() > 0) {
 			cursor.moveToLast();
 			do {

src/eu/siacs/conversations/services/XmppConnectionService.java

@@ -932,6 +932,14 @@ public class XmppConnectionService extends Service {
 		return this.conversations;
 	}
 	
+	public List<Message> getMoreMessages(Conversation conversation,long timestamp) {
+		List<Message> messages = databaseBackend.getMessages(conversation, 50, timestamp);
+		for(Message message : messages) {
+			message.setConversation(conversation);
+		}
+		return messages;
+	}
+
 	public List<Account> getAccounts() {
 		return this.accounts;
 	}

src/eu/siacs/conversations/ui/ConversationFragment.java

@@ -40,6 +40,8 @@ import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.View.OnLongClickListener;
 import android.view.ViewGroup;
+import android.widget.AbsListView.OnScrollListener;
+import android.widget.AbsListView;
 import android.widget.ArrayAdapter;
 import android.widget.Button;
 import android.widget.EditText;
@@ -68,6 +70,7 @@ public class ConversationFragment extends Fragment {
 	protected Bitmap selfBitmap;
 
 	private boolean useSubject = true;
+	private boolean messagesLoaded = false;
 
 	private IntentSender askForPassphraseIntent = null;
 
@@ -118,6 +121,33 @@ public class ConversationFragment extends Fragment {
 			startActivity(intent);
 		}
 	};
+
+	private OnScrollListener mOnScrollListener = new OnScrollListener() {
+
+		@Override
+		public void onScrollStateChanged(AbsListView view, int scrollState) {
+			// TODO Auto-generated method stub
+
+		}
+
+		@Override
+		public void onScroll(AbsListView view, int firstVisibleItem,
+				int visibleItemCount, int totalItemCount) {
+			if (firstVisibleItem == 0 && messagesLoaded) {
+				long timestamp = messageList.get(0).getTimeSent();
+				messagesLoaded = false;
+				List<Message> messages = activity.xmppConnectionService
+						.getMoreMessages(conversation, timestamp);
+				messageList.addAll(0, messages);
+				messageListAdapter.notifyDataSetChanged();
+				if (messages.size() != 0) {
+					messagesLoaded = true;
+				}
+				messagesView.setSelectionFromTop(messages.size() + 1, 0);
+			}
+		}
+	};
+
 	private ConversationActivity activity;
 
 	public void hidePgpPassphraseBox() {
@@ -163,6 +193,7 @@ public class ConversationFragment extends Fragment {
 		mucErrorText = (TextView) view.findViewById(R.id.muc_error_msg);
 
 		messagesView = (ListView) view.findViewById(R.id.messages_view);
+		messagesView.setOnScrollListener(mOnScrollListener);
 		messagesView.setTranscriptMode(ListView.TRANSCRIPT_MODE_NORMAL);
 
 		messageListAdapter = new ArrayAdapter<Message>(this.getActivity()
@@ -510,7 +541,8 @@ public class ConversationFragment extends Fragment {
 						} else {
 							displayInfoMessage(viewHolder,
 									R.string.install_openkeychain);
-							viewHolder.message_box.setOnClickListener(new OnClickListener() {
+							viewHolder.message_box
+									.setOnClickListener(new OnClickListener() {
 
 										@Override
 										public void onClick(View v) {
@@ -685,12 +717,14 @@ public class ConversationFragment extends Fragment {
 			}
 			if (this.conversation.getMessages().size() == 0) {
 				this.messageList.clear();
+				messagesLoaded = false;
 			} else {
-				for(Message message : this.conversation.getMessages()) {
+				for (Message message : this.conversation.getMessages()) {
 					if (!this.messageList.contains(message)) {
 						this.messageList.add(message);
 					}
 				}
+				messagesLoaded = true;
 				updateStatusMessages();
 			}
 			this.messageListAdapter.notifyDataSetChanged();