奇怪的问题又增加了

netrain_flutter_app/lib/douwen/dwMain.dart

+import 'package:flutter/material.dart';
+import 'package:fluttertoast/fluttertoast.dart';
+
+import 'second1.dart';
+
+void main() {
+  runApp(MyApp());
+  // runApp(Login());
+  // runApp(TestPage());
+
+  print("启动");
+}
+
+class MyApp extends StatelessWidget {
+  // This widget is the root of your application.
+  @override
+  Widget build(BuildContext context) {
+    return WillPopScope(
+        child: MaterialApp(
+          title: 'Flutter Demo',
+          initialRoute: "/key1",
+          theme: ThemeData(
+            primarySwatch: Colors.blue,
+            visualDensity: VisualDensity.adaptivePlatformDensity,
+          ),
+          home: Scaffold(
+            appBar: AppBar(
+              title: Text("路由"),
+            ),
+            body: RouterNavigator(title: 'Flutter Demo Home Page'),
+          ),
+          // routes: <String, WidgetBuilder>{"/key2": (context) => second()},
+        ),
+        onWillPop: () async {
+          Fluttertoast.showToast(msg: "退出");
+          return true;
+        });
+  }
+}
+
+class RouterNavigator extends StatefulWidget {
+  RouterNavigator({Key key, this.title}) : super(key: key);
+  final String title;
+
+  @override
+  _RouterNavigatorState createState() => _RouterNavigatorState();
+}
+
+class _RouterNavigatorState extends State<RouterNavigator> {
+  bool byName = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      child: Column(
+        children: [
+          _item("跳转", () {
+            Navigator.push(
+                context, MaterialPageRoute(builder: (context) => Second()));
+          })
+        ],
+      ),
+    );
+  }
+
+  _item(String title, VoidCallback onPressed) {
+    return Container(
+      child: RaisedButton(
+        onPressed: onPressed,
+        child: Text(title),
+      ),
+    );
+  }
+}

netrain_flutter_app/lib/douwen/second1.dart

+import 'package:flutter/material.dart';
+import 'package:fluttertoast/fluttertoast.dart';
+
+
+class Second extends StatelessWidget{
+  @override
+  Widget build(BuildContext context) {
+    return WillPopScope(
+        child: MaterialApp(
+          title: 'Flutter Demo',
+          theme: ThemeData(
+            primarySwatch: Colors.blue,
+            visualDensity: VisualDensity.adaptivePlatformDensity,
+          ),
+          home: Scaffold(
+            appBar: AppBar(
+              title: Text("·2"),
+            ),
+            body: RouterNavigator(title: 'Flutter Demo Home Page'),
+          ),
+        ),
+        onWillPop: () async {
+          Fluttertoast.showToast(msg: "˳");
+          return true;
+        });
+  }
+
+}
+
+
+class RouterNavigator extends StatefulWidget {
+  RouterNavigator({Key key, this.title}) : super(key: key);
+  final String title;
+
+  @override
+  _RouterNavigatorState createState() => _RouterNavigatorState();
+}
+
+class _RouterNavigatorState extends State<RouterNavigator> {
+  bool byName = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return Container(
+      child: Column(
+        children: [
+          _item("ת", () {
+            Navigator.push(
+                context, MaterialPageRoute(builder: (context) => Second()));
+          })
+        ],
+      ),
+    );
+  }
+
+  _item(String title, VoidCallback onPressed) {
+    return Container(
+      child: RaisedButton(
+        onPressed: onPressed,
+        child: Text(title),
+      ),
+    );
+  }
+}
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