Attempted tab-next support. Closes #54

Author: danvick

lib/src/form_builder.dart

@@ -166,7 +166,7 @@ class FormBuilderState extends State<FormBuilder> {
   Widget build(BuildContext context) {
     return Form(
       key: _formKey,
-      child: widget.child,
+      child: FocusTraversalGroup(child: widget.child),
       autovalidate: widget.autovalidate,
       onWillPop: widget.onWillPop,
       onChanged: () {

lib/src/form_builder_field.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/scheduler.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_form_builder/flutter_form_builder.dart';
 
 class FormBuilderField<T> extends FormField<T> {
@@ -72,6 +73,8 @@ class FormBuilderFieldState<T> extends FormFieldState<T> {
 
   FocusNode _node;
 
+  FocusAttachment _nodeAttachment;
+
   bool _focused = false;
 
   @override
@@ -87,7 +90,7 @@ class FormBuilderFieldState<T> extends FormFieldState<T> {
             : null);
     _node = widget.focusNode ?? FocusNode(debugLabel: '${widget.attribute}');
     _node.addListener(_handleFocusChange);
-    // _nodeAttachment = _node.attach(context, onKey: _handleKeyPress);
+    _nodeAttachment = _node.attach(context, onKey: _handleKeyPress);
     setValue(_initialValue);
   }
 
@@ -99,6 +102,17 @@ class FormBuilderFieldState<T> extends FormFieldState<T> {
     }
   }
 
+  bool _handleKeyPress(FocusNode node, RawKeyEvent event) {
+    if (event is RawKeyDownEvent) {
+      print('Focus node ${node.debugLabel} got key event: ${event.logicalKey}');
+      if (event.logicalKey == LogicalKeyboardKey.tab) {
+        FocusScope.of(context).nextFocus();
+        return true;
+      }
+    }
+    return false;
+  }
+
   @override
   void dispose() {
     _formBuilderState?.unregisterFieldKey(widget.attribute);