remember scroll position on rotate. fixes #2011

2 files changed, 62 insertions, 14 deletions

diff --git a/src/main/java/de/pixart/messenger/ui/ConversationActivity.java b/src/main/java/de/pixart/messenger/ui/ConversationActivity.java
index 8e596303b..6d03cb5d6 100644
--- a/src/main/java/de/pixart/messenger/ui/ConversationActivity.java
+++ b/src/main/java/de/pixart/messenger/ui/ConversationActivity.java
@@ -110,12 +110,15 @@ public class ConversationActivity extends XmppActivity
 	private static final String STATE_OPEN_CONVERSATION = "state_open_conversation";
 	private static final String STATE_PANEL_OPEN = "state_panel_open";
 	private static final String STATE_PENDING_URI = "state_pending_uri";
+    private static final String STATE_FIRST_VISIBLE = "first_visible";
+    private static final String STATE_OFFSET_FROM_TOP = "offset_from_top";
 	final private List<Uri> mPendingImageUris = new ArrayList<>();
     final private List<Uri> mPendingPhotoUris = new ArrayList<>();
 	final private List<Uri> mPendingFileUris = new ArrayList<>();
     final private List<Uri> mPendingVideoUris = new ArrayList<>();
-	private String mOpenConverstaion = null;
+	private String mOpenConversation = null;
 	private boolean mPanelOpen = true;
+    private Pair<Integer,Integer> mScrollPosition = null;
 	private Uri mPendingGeoUri = null;
 	private boolean forbidProcessingPendings = false;
 	private Message mPendingDownloadableMessage = null;
@@ -191,9 +194,17 @@ public class ConversationActivity extends XmppActivity
 	protected void onCreate(final Bundle savedInstanceState) {
 		super.onCreate(savedInstanceState);
 		if (savedInstanceState != null) {
-			mOpenConverstaion = savedInstanceState.getString(STATE_OPEN_CONVERSATION, null);
+			mOpenConversation = savedInstanceState.getString(STATE_OPEN_CONVERSATION, null);
 			mPanelOpen = savedInstanceState.getBoolean(STATE_PANEL_OPEN, true);
-			String pending = savedInstanceState.getString(STATE_PENDING_URI, null);
+            int pos = savedInstanceState.getInt(STATE_FIRST_VISIBLE, -1);
+            int offset = savedInstanceState.getInt(STATE_OFFSET_FROM_TOP, 1);
+            if (pos >= 0 && offset <= 0) {
+                Log.d(Config.LOGTAG, "retrieved scroll position from instanceState " + pos + ":" + offset);
+                mScrollPosition = new Pair<>(pos, offset);
+            } else {
+                mScrollPosition = null;
+            }
+            String pending = savedInstanceState.getString(STATE_PENDING_URI, null);
 			if (pending != null) {
 				mPendingImageUris.clear();
 				mPendingImageUris.add(Uri.parse(pending));
@@ -1274,7 +1285,7 @@ public class ConversationActivity extends XmppActivity
 	@Override
 	protected void onNewIntent(final Intent intent) {
 		if (intent != null && ACTION_VIEW_CONVERSATION.equals(intent.getAction())) {
-			mOpenConverstaion = null;
+			mOpenConversation = null;
 			if (xmppConnectionServiceBound) {
 				handleViewConversationIntent(intent);
 				intent.setAction(Intent.ACTION_MAIN);
@@ -1323,7 +1334,12 @@ public class ConversationActivity extends XmppActivity
 		Conversation conversation = getSelectedConversation();
 		if (conversation != null) {
 			savedInstanceState.putString(STATE_OPEN_CONVERSATION, conversation.getUuid());
-		} else {
+            Pair<Integer, Integer> scrollPosition = mConversationFragment.getScrollPosition();
+            if (scrollPosition != null) {
+                savedInstanceState.putInt(STATE_FIRST_VISIBLE, scrollPosition.first);
+                savedInstanceState.putInt(STATE_OFFSET_FROM_TOP, scrollPosition.second);
+            }
+        } else {
 			savedInstanceState.remove(STATE_OPEN_CONVERSATION);
 		}
 		savedInstanceState.putBoolean(STATE_PANEL_OPEN, isConversationsOverviewVisable());
@@ -1411,7 +1427,7 @@ public class ConversationActivity extends XmppActivity
 				}
 				finish();
 			}
-		} else if (selectConversationByUuid(mOpenConverstaion)) {
+		} else if (selectConversationByUuid(mOpenConversation)) {
 			if (mPanelOpen) {
 				showConversationsOverview();
 			} else {
@@ -1420,9 +1436,12 @@ public class ConversationActivity extends XmppActivity
 					updateActionBarTitle(true);
 				}
 			}
-			this.mConversationFragment.reInit(getSelectedConversation());
-			mOpenConverstaion = null;
-		} else if (intent != null && ACTION_VIEW_CONVERSATION.equals(intent.getAction())) {
+            if (this.mConversationFragment.reInit(getSelectedConversation())) {
+                Log.d(Config.LOGTAG, "setting scroll position on fragment");
+                this.mConversationFragment.setScrollPosition(mScrollPosition);
+            }
+            mOpenConversation = null;
+        } else if (intent != null && ACTION_VIEW_CONVERSATION.equals(intent.getAction())) {
 			clearPending();
 			handleViewConversationIntent(intent);
 			intent.setAction(Intent.ACTION_MAIN);
diff --git a/src/main/java/de/pixart/messenger/ui/ConversationFragment.java b/src/main/java/de/pixart/messenger/ui/ConversationFragment.java
index 736c07aa9..1c9e215af 100644
--- a/src/main/java/de/pixart/messenger/ui/ConversationFragment.java
+++ b/src/main/java/de/pixart/messenger/ui/ConversationFragment.java
@@ -12,6 +12,8 @@ import android.content.IntentSender.SendIntentException;
 import android.os.Bundle;
 import android.os.Handler;
 import android.text.InputType;
+import android.util.Log;
+import android.util.Pair;
 import android.view.ContextMenu;
 import android.view.ContextMenu.ContextMenuInfo;
 import android.view.Gravity;
@@ -153,8 +155,12 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 									View v = messagesView.getChildAt(0);
 									final int pxOffset = (v == null) ? 0 : v.getTop();
 									ConversationFragment.this.conversation.populateWithMessages(ConversationFragment.this.messageList);
-									updateStatusMessages();
-									messageListAdapter.notifyDataSetChanged();
+                                    try {
+                                        updateStatusMessages();
+                                    } catch (IllegalStateException e) {
+                                        Log.d(Config.LOGTAG, "caught illegal state exception while updating status messages");
+                                    }
+                                    messageListAdapter.notifyDataSetChanged();
 									int pos = Math.max(getIndexOf(uuid,messageList),0);
 									messagesView.setSelectionFromTop(pos, pxOffset);
 									messagesLoaded = true;
@@ -210,7 +216,29 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 		}
 		return -1;
 	}
-	protected OnClickListener clickToDecryptListener = new OnClickListener() {
+
+    public Pair<Integer, Integer> getScrollPosition() {
+        if (this.messagesView.getCount() == 0 ||
+                this.messagesView.getLastVisiblePosition() == this.messagesView.getCount() - 1) {
+            return null;
+        } else {
+            final int pos = messagesView.getFirstVisiblePosition();
+            final View view = messagesView.getChildAt(0);
+            if (view == null) {
+                return null;
+            } else {
+                return new Pair<>(pos, view.getTop());
+            }
+        }
+    }
+
+    public void setScrollPosition(Pair<Integer, Integer> scrollPosition) {
+        if (scrollPosition != null) {
+            this.messagesView.setSelectionFromTop(scrollPosition.first, scrollPosition.second);
+        }
+    }
+
+    protected OnClickListener clickToDecryptListener = new OnClickListener() {
 
 		@Override
 		public void onClick(View v) {
@@ -747,9 +775,9 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 		}
 	}
 
-	public void reInit(Conversation conversation) {
+	public boolean reInit(Conversation conversation) {
 		if (conversation == null) {
-			return;
+			return false;
 		}
 		this.activity = (ConversationActivity) getActivity();
 		setupIme();
@@ -785,6 +813,7 @@ public class ConversationFragment extends Fragment implements EditMessage.Keyboa
 				pos = i < 0 ? bottom : i;
 			}
 			messagesView.setSelection(pos);
+            return pos == bottom;
 		}
 	}