basic file management for transactions

loc_chain_app/lib/pages/history.dart

@@ -0,0 +1,52 @@
+import 'package:flutter/material.dart';
+
+class HomePage extends StatefulWidget {
+  HomePage({Key? key, required this.title}) : super(key: key);
+  final String title;
+
+  @override
+  _HomePageState createState() => _HomePageState();
+}
+
+class _HomePageState extends State<HomePage> {
+  int _counter = 0;
+
+  void _incrementCounter() {
+    setState(() {
+      // This call to setState tells the Flutter framework that something has
+      // changed in this State, which causes it to rerun the build method below
+      // so that the display can reflect the updated values. If we changed
+      // _counter without calling setState(), then the build method would not be
+      // called again, and so nothing would appear to happen.
+      _counter++;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text(widget.title),
+      ),
+      body: Center(
+        child: Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          children: <Widget>[
+            Text(
+              'You have pushed the button this many times:',
+            ),
+            Text(
+              '$_counter',
+              style: Theme.of(context).textTheme.headline4,
+            ),
+          ],
+        ),
+      ),
+      floatingActionButton: FloatingActionButton(
+        onPressed: _incrementCounter,
+        tooltip: 'Increment',
+        child: Icon(Icons.add),
+      ),
+    );
+  }
+}