Make compose box behave similarly on all modes.

Fixes #178.

Author: reachme-ankita

app/src/main/java/com/zulip/android/activities/ZulipActivity.java

@@ -259,10 +259,35 @@ public void muteTopic(Message message) {
 
     @Override
     public void recyclerViewScrolled() {
-        if (chatBox.getVisibility() == View.VISIBLE && !isTextFieldFocused) {
+            /* in this method we check if the messageEt is empty or not
+            if messageEt is not empty, it means that the user has typed something in the chatBox and that the chatBox should be open
+            in spite of scrolling */
+        if(chatBox.getVisibility()== View.VISIBLE && !isCurrentModeStream()){
+            //if messageEt is empty in private msg mode, then the chatBox can disappear on scrolling else it will stay
+            if(messageEt.getText().toString().equals(""))
+            {
+                displayChatBox(false);
+                displayFAB(true);
+
+            }
+        }
+
+        else if(chatBox.getVisibility()==View.VISIBLE && isCurrentModeStream()){
+            //check if messageEt is empty in stream msg mode, then the chatBox can disappear on scrolling else it will disappear
+            if(messageEt.getText().toString().equals("") && topicActv.getText().toString().equals(""))
+            {
+                displayChatBox(false);
+                displayFAB(true);
+
+            }
+        }
+        /*check if stream edittext, topic edittext and messageEt edittext is empty in a general msg mode(i.e. when the floating
+        button is pressed by user). If all fields are empty, then on scrolling the chatBox will disappear else not  */
+        else if (chatBox.getVisibility() == View.VISIBLE && streamActv.getText().toString().equals("") && topicActv.getText().toString().equals("") && messageEt.getText().toString().equals("")) {
             displayChatBox(false);
             displayFAB(true);
         }
+
     }
 
     public RefreshableCursorAdapter getPeopleAdapter() {