add constant app

ios/Flutter/Debug.xcconfig

+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
 #include "Generated.xcconfig"

ios/Flutter/Release.xcconfig

+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
 #include "Generated.xcconfig"

ios/Podfile

+# Uncomment this line to define a global platform for your project
+# platform :ios, '9.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def parse_KV_file(file, separator='=')
+  file_abs_path = File.expand_path(file)
+  if !File.exists? file_abs_path
+    return [];
+  end
+  generated_key_values = {}
+  skip_line_start_symbols = ["#", "/"]
+  File.foreach(file_abs_path) do |line|
+    next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
+    plugin = line.split(pattern=separator)
+    if plugin.length == 2
+      podname = plugin[0].strip()
+      path = plugin[1].strip()
+      podpath = File.expand_path("#{path}", file_abs_path)
+      generated_key_values[podname] = podpath
+    else
+      puts "Invalid plugin specification: #{line}"
+    end
+  end
+  generated_key_values
+end
+
+target 'Runner' do
+  use_frameworks!
+  use_modular_headers!
+
+  # Flutter Pod
+
+  copied_flutter_dir = File.join(__dir__, 'Flutter')
+  copied_framework_path = File.join(copied_flutter_dir, 'Flutter.framework')
+  copied_podspec_path = File.join(copied_flutter_dir, 'Flutter.podspec')
+  unless File.exist?(copied_framework_path) && File.exist?(copied_podspec_path)
+    # Copy Flutter.framework and Flutter.podspec to Flutter/ to have something to link against if the xcode backend script has not run yet.
+    # That script will copy the correct debug/profile/release version of the framework based on the currently selected Xcode configuration.
+    # CocoaPods will not embed the framework on pod install (before any build phases can generate) if the dylib does not exist.
+
+    generated_xcode_build_settings_path = File.join(copied_flutter_dir, 'Generated.xcconfig')
+    unless File.exist?(generated_xcode_build_settings_path)
+      raise "Generated.xcconfig must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+    end
+    generated_xcode_build_settings = parse_KV_file(generated_xcode_build_settings_path)
+    cached_framework_dir = generated_xcode_build_settings['FLUTTER_FRAMEWORK_DIR'];
+
+    unless File.exist?(copied_framework_path)
+      FileUtils.cp_r(File.join(cached_framework_dir, 'Flutter.framework'), copied_flutter_dir)
+    end
+    unless File.exist?(copied_podspec_path)
+      FileUtils.cp(File.join(cached_framework_dir, 'Flutter.podspec'), copied_flutter_dir)
+    end
+  end
+
+  # Keep pod path relative so it can be checked into Podfile.lock.
+  pod 'Flutter', :path => 'Flutter'
+
+  # Plugin Pods
+
+  # Prepare symlinks folder. We use symlinks to avoid having Podfile.lock
+  # referring to absolute paths on developers' machines.
+  system('rm -rf .symlinks')
+  system('mkdir -p .symlinks/plugins')
+  plugin_pods = parse_KV_file('../.flutter-plugins')
+  plugin_pods.each do |name, path|
+    symlink = File.join('.symlinks', 'plugins', name)
+    File.symlink(path, symlink)
+    pod name, :path => File.join(symlink, 'ios')
+  end
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      config.build_settings['ENABLE_BITCODE'] = 'NO'
+    end
+  end
+end

lib/app/my_app.dart

 import 'package:farm_tpf/app/themes.dart';
+import 'package:farm_tpf/utils/const_string.dart';
 import 'package:flutter/material.dart';
 
 class MyApp extends StatelessWidget {
 class MyHomePage extends StatefulWidget {
   MyHomePage({Key key, this.title}) : super(key: key);
 
-  // This widget is the home page of your application. It is stateful, meaning
-  // that it has a State object (defined below) that contains fields that affect
-  // how it looks.
-
-  // This class is the configuration for the state. It holds the values (in this
-  // case the title) provided by the parent (in this case the App widget) and
-  // used by the build method of the State. Fields in a Widget subclass are
-  // always marked "final".
-
   final String title;
 
   @override
 
   @override
   Widget build(BuildContext context) {
-    // This method is rerun every time setState is called, for instance as done
-    // by the _incrementCounter method above.
-    //
-    // The Flutter framework has been optimized to make rerunning build methods
-    // fast, so that you can just rebuild anything that needs updating rather
-    // than having to individually change instances of widgets.
     return Scaffold(
-      appBar: AppBar(
-        // Here we take the value from the MyHomePage object that was created by
-        // the App.build method, and use it to set our appbar title.
-        title: Text(widget.title),
-        actions: [
-          IconButton(
-            icon: Icon(Icons.flip, color: Colors.white),
-            onPressed: _theme?.switchTheme,
-          ),
-        ],
-      ),
-      body: Center(
-        // Center is a layout widget. It takes a single child and positions it
-        // in the middle of the parent.
-        child: Column(
-          // Column is also a layout widget. It takes a list of children and
-          // arranges them vertically. By default, it sizes itself to fit its
-          // children horizontally, and tries to be as tall as its parent.
-          //
-          // Invoke "debug painting" (press "p" in the console, choose the
-          // "Toggle Debug Paint" action from the Flutter Inspector in Android
-          // Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
-          // to see the wireframe for each widget.
-          //
-          // Column has various properties to control how it sizes itself and
-          // how it positions its children. Here we use mainAxisAlignment to
-          // center the children vertically; the main axis here is the vertical
-          // axis because Columns are vertical (the cross axis would be
-          // horizontal).
-          mainAxisAlignment: MainAxisAlignment.center,
-          children: <Widget>[
-            Text(
-              'You have pushed the button this many times:',
-            ),
-            Text(
-              '$_counter',
-              style: Theme.of(context).textTheme.headline4,
+        appBar: AppBar(
+          title: Text(widget.title),
+          actions: [
+            IconButton(
+              icon: Icon(Icons.flip, color: Colors.white),
+              onPressed: _theme?.switchTheme,
             ),
           ],
         ),
-      ),
-      floatingActionButton: FloatingActionButton(
-        onPressed: _incrementCounter,
-        tooltip: 'Increment',
-        child: Icon(Icons.add),
-      ), // This trailing comma makes auto-formatting nicer for build methods.
-    );
+        body: Center(child: Text(app_name)));
   }
 }

lib/utils/const_string.dart

+const String app_name = "app name";

lib/utils/pref.dart

+import 'package:shared_preferences/shared_preferences.dart';
+
+class LocalPref extends Pref {
+  @override
+  Future<bool> saveString(String key, String value) async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.setString(key, value);
+  }
+
+  @override
+  Future<String> getString(String key) async {
+    final prefs = await SharedPreferences.getInstance();
+    return prefs.getString(key);
+  }
+}
+
+abstract class Pref {
+  Future<bool> saveString(String key, String value);
+
+  Future<String> getString(String key);
+}
+
+class PrefKey {
+  static const String token_key = "token_key";
+  static const String expired_time = "expired_time";
+}

pubspec.lock

       url: "https://pub.dartlang.org"
     source: hosted
     version: "0.1.3"
+  file:
+    dependency: transitive
+    description:
+      name: file
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "5.2.1"
   flutter:
     dependency: "direct main"
     description: flutter
     description: flutter
     source: sdk
     version: "0.0.0"
+  flutter_web_plugins:
+    dependency: transitive
+    description: flutter
+    source: sdk
+    version: "0.0.0"
   image:
     dependency: transitive
     description:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.12"
+  intl:
+    dependency: transitive
+    description:
+      name: intl
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.16.1"
   matcher:
     dependency: transitive
     description:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.6.4"
+  path_provider_linux:
+    dependency: transitive
+    description:
+      name: path_provider_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+2"
+  path_provider_platform_interface:
+    dependency: transitive
+    description:
+      name: path_provider_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.2"
   petitparser:
     dependency: transitive
     description:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.4.0"
+  platform:
+    dependency: transitive
+    description:
+      name: platform
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "2.2.1"
+  plugin_platform_interface:
+    dependency: transitive
+    description:
+      name: plugin_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.2"
+  process:
+    dependency: transitive
+    description:
+      name: process
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "3.0.13"
   provider:
     dependency: "direct main"
     description:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.3"
+  shared_preferences:
+    dependency: "direct main"
+    description:
+      name: shared_preferences
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.5.8"
+  shared_preferences_linux:
+    dependency: transitive
+    description:
+      name: shared_preferences_linux
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.2+1"
+  shared_preferences_macos:
+    dependency: transitive
+    description:
+      name: shared_preferences_macos
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.0.1+10"
+  shared_preferences_platform_interface:
+    dependency: transitive
+    description:
+      name: shared_preferences_platform_interface
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.4"
+  shared_preferences_web:
+    dependency: transitive
+    description:
+      name: shared_preferences_web
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.2+7"
   sky_engine:
     dependency: transitive
     description: flutter
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.0.8"
+  xdg_directories:
+    dependency: transitive
+    description:
+      name: xdg_directories
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.1.0"
   xml:
     dependency: transitive
     description:
     version: "3.6.1"
 sdks:
   dart: ">=2.7.0 <3.0.0"
-  flutter: ">=1.16.0"
+  flutter: ">=1.16.0 <2.0.0"

pubspec.yaml

   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^0.1.3
   provider: ^4.3.1
+  shared_preferences: ^0.5.8
 
 dev_dependencies:
   flutter_test: