Flutter 包 (Package) 專案範例

　　Flutter 的包(Package)專案範例，提供建立以純Dart語言包(Package)的專案架構。

1.　　建立新的Flutter專案

　　1-1.　　開啟命令介面

　　1-2.　　選擇建立包(Package) 專案類型

　　1-3.　　輸入專案名稱

2.　　Flutter 預設包專案的檔案架構

　在選擇建立新的包專案後會自動產生相關的檔案及目錄，主要的檔案如下：

　　2-1.　　lib 目錄

library flutter_package;
/// A Calculator.
class Calculator {
  /// Returns [value] plus 1.
  int addOne(int value) => value + 1;
}

　　2-2.　　test 目錄

import 'packag:flutter_test/flutter_test.dart';
import 'package:flutter_package/flutter_package.dart';
void main() {
　　test('adds one to input values', () {
    　　final calculator = Calculator();
      　　expect(calculator.addOne(2), 3);
      　　expect(calculator.addOne(-7), -6);
      　　expect(calculator.addOne(0), 1);
　　});
}

　　2-3.　　pubspec.yaml檔案

name: flutter_package
description: A new Flutter package project.
version: 0.0.1
homepage:
environment:
  sdk: ">=2.15.1 <3.0.0"
  flutter: ">=1.17.0"
dependencies:
  flutter:
    sdk: flutter
dev_dependencies:
  flutter_test:
    sdk: flutter
  flutter_lints: ^1.0.0
flutter:

　　2-4.　　.packages檔案

async:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/async-2.8.2/lib/
boolean_selector:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/boolean_selector-2.1.0/lib/
characters:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.2.0/lib/
charcode:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.3.1/lib/
clock:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0/lib/
collection:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/collection-1.15.0/lib/
fake_async:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/fake_async-1.2.0/lib/
flutter:file:///D:/flutter_windows_2.8.1-stable/flutter/packages/flutter/lib/
flutter_lints:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_lints-1.0.4/lib/
flutter_test:file:///D:/flutter_windows_2.8.1-stable/flutter/packages/flutter_test/lib/
lints:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/lints-1.0.1/lib/
matcher:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/matcher-0.12.11/lib/
meta:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/meta-1.7.0/lib/
path:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0/lib/
sky_engine:file:///D:/flutter_windows_2.8.1-stable/flutter/bin/cache/pkg/sky_engine/lib/
source_span:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.1/lib/
stack_trace:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/stack_trace-1.10.0/lib/
stream_channel:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/stream_channel-2.1.0/lib/
string_scanner:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/string_scanner-1.1.0/lib/
term_glyph:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0/lib/
test_api:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.4.3/lib/
typed_data:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0/lib/
vector_math:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.1/lib/
flutter_package:lib/

3.　　執行各平台Flutter 偵錯自訂包(Package)

　　建立新的應用程式專案用來載入並使用自訂包(Package)的定義類別。

　　3-1.　　新增自訂包(Package)路徑　　

name: flutter_application
description: A new Flutter project.
publish_to: 'none' 
version: 1.0.0+1
environment:
  sdk: ">=2.15.1 <3.0.0"
dependencies:
　　flutter:
　　　　sdk: flutter
   
　　flutter_package:
　　　　path: C:/Users/yuanj/Desktop/flutter_package
　　cupertino_icons: ^1.0.2
dev_dependencies:
　　flutter_test:
　　　　sdk: flutter
　　flutter_lints: ^1.0.0
flutter:
　　uses-material-design: true

async:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/async-2.8.2/lib/
boolean_selector:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/boolean_selector-2.1.0/lib/
characters:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/characters-1.2.0/lib/
charcode:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/charcode-1.3.1/lib/
clock:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/clock-1.1.0/lib/
collection:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/collection-1.15.0/lib/
cupertino_icons:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/cupertino_icons-1.0.4/lib/
fake_async:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/fake_async-1.2.0/lib/
flutter:file:///D:/flutter_windows_2.8.1-stable/flutter/packages/flutter/lib/
flutter_lints:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/flutter_lints-1.0.4/lib/
flutter_package:file:///C:/Users/yuanj/Desktop/flutter_package/lib/
flutter_test:file:///D:/flutter_windows_2.8.1-stable/flutter/packages/flutter_test/lib/
lints:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/lints-1.0.1/lib/
matcher:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/matcher-0.12.11/lib/
meta:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/meta-1.7.0/lib/
path:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/path-1.8.0/lib/
sky_engine:file:///D:/flutter_windows_2.8.1-stable/flutter/bin/cache/pkg/sky_engine/lib/
source_span:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/source_span-1.8.1/lib/
stack_trace:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/stack_trace-1.10.0/lib/
stream_channel:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/stream_channel-2.1.0/lib/
string_scanner:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/string_scanner-1.1.0/lib/
term_glyph:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/term_glyph-1.2.0/lib/
test_api:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/test_api-0.4.3/lib/
typed_data:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/typed_data-1.3.0/lib/
vector_math:file:///D:/flutter_windows_2.8.1-stable/flutter/.pub-cache/hosted/pub.dartlang.org/vector_math-2.1.1/lib/
flutter_application:lib/

　　3-2.　　載入自訂包(Package)

import 'package:flutter/material.dart';
import 'package:flutter_package/flutter_package.dart';
void main() {
　　runApp(const MyApp());
}
class MyApp extends StatelessWidget {
　　const MyApp({Key? key}) : super(key: key);
　　@override
　　Widget build(BuildContext context) {
　　　　return MaterialApp(
　　　　　　title: 'Flutter Demo',
　　　　　　theme: ThemeData(
　　　　　　　　primarySwatch: Colors.blue,
　　　　　　),
　　　　　　home: const MyHomePage(title: 'Flutter Demo Home Page'),
　　　);
　　}
}
class MyHomePage extends StatefulWidget {
　　const MyHomePage({Key? key, required this.title}) : super(key: key);
　　final String title;
　　@override
　　State<MyHomePage> createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
　　int _counter = 0;
　　void _incrementCounter() {
　　　　setState(() {
　　　　　　_counter++;
　　　　});
　　}
　　@override
　　Widget build(BuildContext context) {
  
　　final  calculator = Calculator();
　　final _counter2 =  calculator.addOne(_counter);
　　return Scaffold(
　　　　appBar: AppBar(
　　　　　　title: Text(widget.title),
　　　　),
　　　　body: Center(
　　　　　　child: Column(
　　　　　　　　mainAxisAlignment: MainAxisAlignment.center,
　　　　　　　　children: <Widget>[           
　　　　　　　　　　const Text(
　　　　　　　　　　　　'You have pushed the button this many times:', 
　　　　　　　　　　),
　　　　　　　　　　Text(
　　　　　　　　　　　　'$_counter',
　　　　　　　　　　　　style: Theme.of(context).textTheme.headline4,
　　　　　　　　　　),
　　　　　　　　　　Text(
　　　　　　　　　　　　"The addOne Value of Calculator Class : $_counter2",
　　　　　　　　　　),
　　　　　　　　],
　　　　　　),
　　　　),
　　　　floatingActionButton: FloatingActionButton(
　　　　　　onPressed: _incrementCounter,
　　　　　　tooltip: 'Increment',
　　　　　　child: const Icon(Icons.add),
　　　　), 
　　);
}}

　　3-3.　　各平台中執行自訂包(Package)相關函式

• 　　Windows Desktop

• 　　Chrome Web

• 　　Linux APP (Ubuntu)

• 　　Android APP