Merge pull request #39 from GetStream/feature/messageInputInitialMessage

add initialMessage property to MessageInput

lib/src/message_input.dart

@@ -71,11 +71,15 @@ class MessageInput extends StatefulWidget {
     this.disableAttachments = false,
     this.doImageUploadRequest,
     this.doFileUploadRequest,
+    this.initialMessage,
   }) : super(key: key);
 
   /// Message to edit
   final Message editMessage;
 
+  /// Message to start with
+  final Message initialMessage;
+
   /// Function called after sending the message
   final void Function(Message) onMessageSent;
 
@@ -763,7 +767,7 @@ class _MessageInputState extends State<MessageInput> {
 
       sendingFuture = StreamChat.of(context).client.updateMessage(message);
     } else {
-      message = Message(
+      message = (widget.initialMessage ?? Message()).copyWith(
         parentId: widget.parentMessage?.id,
         text: text,
         attachments: _getAttachments(attachments).toList(),
@@ -839,12 +843,21 @@ class _MessageInputState extends State<MessageInput> {
     });
 
     if (widget.editMessage != null) {
-      _textController = TextEditingController(text: widget.editMessage.text);
+      _parseExistingMessage(widget.editMessage);
+    } else if (widget.initialMessage != null) {
+      _parseExistingMessage(widget.initialMessage);
+    } else {
+      _textController = TextEditingController();
+    }
+  }
+
+  void _parseExistingMessage(Message message) {
+    _textController = TextEditingController(text: message.text);
 
     _typingStarted = true;
     _messageIsPresent = true;
 
-      widget.editMessage.attachments.forEach((attachment) {
+    message.attachments?.forEach((attachment) {
       if (attachment.type == 'image') {
         _attachments.add(_SendingAttachment(
           type: FileType.image,
@@ -868,9 +881,6 @@ class _MessageInputState extends State<MessageInput> {
         ));
       }
     });
-    } else {
-      _textController = TextEditingController();
-    }
   }
 
   @override