From 2041133491425a86cf2225e85f2c21aa62afd32b Mon Sep 17 00:00:00 2001
From: cjl_macbook <cjl_spy@163.com>
Date: Tue, 7 Aug 2018 07:18:23 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E6=94=B9=E4=BA=86dart=E9=80=BB?=
 =?UTF-8?q?=E8=BE=91?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 web/index.html |  2 +-
 web/main.dart  | 30 ++++++++++++++++++++++++------
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/web/index.html b/web/index.html
index dd9d0a1..d42fff9 100644
--- a/web/index.html
+++ b/web/index.html
@@ -22,7 +22,7 @@
         </div>
         <textarea id="json" title="json字符串"></textarea>
         <div>
-            <button id="format">点击</button>
+            <button id="format">格式化</button>
         </div>
     </div>
     <div id="output" class="textarea">
diff --git a/web/main.dart b/web/main.dart
index 92ee41f..50ffa91 100644
--- a/web/main.dart
+++ b/web/main.dart
@@ -4,17 +4,35 @@ import 'dart:html';
 import 'package:json2dart_serialization/generator.dart';
 
 void main() {
-  querySelector("#format").onClick.listen((event) {
-    TextAreaElement e = querySelector("#json");
-    var string = e.value;
-    var pretty = formatJson(string);
-    e.value = pretty;
+  TextAreaElement jsonInput = querySelector("#json");
+  jsonInput.onInput.listen((event) {
+    var string = jsonInput.value;
+    String pretty;
+    TextAreaElement result = querySelector("#result");
+    try {
+      pretty = formatJson(string);
+    } on Exception {
+      print("格式化错误");
+      result.value = "不是一个正确的json";
+      return;
+    }
 
     var generator = Generator(string, 'test.dart');
     var dartCode = generator.makeDartCode();
-    TextAreaElement result = querySelector("#result");
+
     result.value = dartCode;
   });
+
+  ButtonElement formatButton = querySelector("#format");
+  formatButton.onClick.listen((click) {
+    String pretty;
+    try {
+      pretty = formatJson(jsonInput.value);
+    } on Exception {
+      return;
+    }
+    jsonInput.value = pretty;
+  });
 }
 
 String formatJson(String jsonString) {