Improved send message form UI

lib/ui/screens/conversation_screen.dart

@@ -97,21 +97,24 @@ class _ConversationScreenState extends State<ConversationScreen> {
         image: image,
       ),
     );
+
+    // In case a message was already written in the input
+    _updatedText(_textEditingController.text);
   }
 
   /// Send a new text message
   Future<void> _submitTextMessage(BuildContext context, String content) async {
-    _submitMessage(
+    if (await _submitMessage(
             context,
             NewConversationMessage(
               conversationID: widget.conversationID,
               message: content,
-      ),
-    );
+            )) ==
+        SendMessageResult.SUCCESS) _clearSendMessageForm();
   }
 
   /// Submit a new message
-  Future<void> _submitMessage(
+  Future<SendMessageResult> _submitMessage(
       BuildContext context, NewConversationMessage message) async {
     //Send the message
     _setSending(true);
@@ -119,9 +122,7 @@ class _ConversationScreenState extends State<ConversationScreen> {
     _setSending(false);
 
     //Check the result of the operation
-    if (result == SendMessageResult.SUCCESS)
-      _clearSendMessageForm();
-    else
+    if (result != SendMessageResult.SUCCESS)
       Scaffold.of(context).showSnackBar(
         SnackBar(
           content: Text(
@@ -132,6 +133,14 @@ class _ConversationScreenState extends State<ConversationScreen> {
           duration: Duration(milliseconds: 500),
         ),
       );
+
+    return result;
+  }
+
+  void _updatedText(String text) {
+    setState(() {
+      _isMessageValid = text.length > 4;
+    });
   }
 
   /// Clear send message form
@@ -173,20 +182,20 @@ class _ConversationScreenState extends State<ConversationScreen> {
             child: new IconButton(
               icon: new Icon(
                 Icons.photo_camera,
-                  color: Theme.of(context).accentColor,
+                color: _isSendingMessage
+                    ? Theme.of(context).disabledColor
+                    : Theme.of(context).accentColor,
+              ),
+              onPressed: () => _sendImage(context),
             ),
-                onPressed: () => _sendImage(context)),
           ),
 
           // Message area
           new Flexible(
             child: new TextField(
+              enabled: !_isSendingMessage,
               controller: _textEditingController,
-              onChanged: (String messageText) {
-                setState(() {
-                  _isMessageValid = messageText.length > 4;
-                });
-              },
+              onChanged: _updatedText,
               onSubmitted: _isMessageValid
                   ? (s) => _submitTextMessage(context, s)
                   : null,