Update README.md

Author: flytreeleft

README.md

@@ -13,7 +13,6 @@ A simple, smart and powerful flutter calculator widget.
 - **Auto-resize** the formula or result font size to adapt the text box's boundary.
 - Supports **undo** and **redo**.
 - Supports to relocate and input symbols.
-- [**WIP**] Supports to specify the result's precision.
 
 ## Getting Started
 
@@ -24,7 +23,7 @@ dependencies:
   flutter_calculator:
     git:
       url: git://github.com/flytreeleft/flutter_calculator.git
-      ref: master
+      ref: bugfix-0.1.x
 ```
 
 - Import package `import 'package:flutter_calculator/flutter_calculator.dart';` and call `await showCalculator(context: context);` in your code:
@@ -52,18 +51,10 @@ class HomePage extends StatefulWidget {
 }
 
 class _HomePageState extends State<HomePage> {
-  final FocusNode _focusNode = FocusNode();
   final TextEditingController _textController = TextEditingController(text: '0.00');
 
-  @override
-  void initState() {
-    this._focusNode.addListener(this._showCalculatorDialog);
-    super.initState();
-  }
-
   @override
   void dispose() {
-    this._focusNode.removeListener(this._showCalculatorDialog);
     this._textController.dispose();
     super.dispose();
   }
@@ -75,21 +66,17 @@ class _HomePageState extends State<HomePage> {
       body: TextField(
         showCursor: false,
         readOnly: true,
-        focusNode: this._focusNode,
         controller: this._textController,
+        onTap: () => this._showCalculatorDialog(),
       ),
     );
   }
 
   void _showCalculatorDialog() async {
-    if (!this._focusNode.hasFocus) {
-      return;
-    }
-
-    final result = await showCalculator(context: this.context);
+    final result = await showCalculator(context: this.context) ?? 0.00;
 
     this._textController.value = this._textController.value.copyWith(
-          text: result?.toString() ?? '0.00',
+          text: result.toStringAsFixed(2),
         );
   }
 }