Flutter 入門路線圖

本文整理自 Roadmap To Become A Flutter Developer，請參考原文閱讀

本文是爲那些渴望開始學習 flutter 的人們而準備的，這是一個適合初學者從全部必要資源中逐步學習的路線圖。

什麼是 flutter

Flutter 是 Google 的 UI 工具包，可經過單個代碼庫爲移動設備，web 和桌面系統構建漂亮的，本機編譯的應用程序。

下面兩個視頻很好地介紹了 flutter；

• Introducing Flutter¹

• What's new in Flutter 2019²

[1] https://youtu.be/fq4N0hgOWzU
[2] https://youtu.be/5VbAwhBBHsg

爲何是 flutter？

咱們已經知道有不少框架能夠提供跨平臺功能，那麼在這場激烈競爭中，是什麼讓 flutter 顯得特別呢？

快速開發

Flutter 的熱加載功能可幫助您快速輕鬆地進行實驗，構建用戶界面，添加功能並更快地修復錯誤。在 iOS 和 Android 的模擬器和硬件上體驗亞秒級的從新加載時間，而不會丟失狀態。

富有表現力的精美用戶界面

Flutter 內置的精美 Material Design 和 Cupertino（iOS-flavor）小部件，豐富的運動 API，流暢的天然滾動以及對平臺的瞭解，可爲您的用戶帶來更多驚喜。

native 級別的性能

Flutter 的小部件結合了全部重要的平臺差別，例如滾動，導航，圖標和字體，以在 iOS 和 Android 上提供完整的 native 性能。

查看 Flutter 的功能

如下是全球開發人員構建的 Flutter 應用程序的展現。

• Apps take flight with Flutter³

• An open list of apps built with Flutter⁴

• Flutter Awesome⁵

• Start Flutter | Forever free, open source, and easy to use.⁶

[3]https://flutter.dev/showcase
[4]https://itsallwidgets.com/
[5]https://flutterawesome.com/
[6]https://startflutter.com/

首先要作什麼？

Flutter 既快速又容易，若是您熟悉 Java 或任何面向對象的語言，那麼很不錯，可是我強烈建議您具有 Dart 的基本知識。

如下是一些可能對您有所幫助的視頻。

• Dart Programming for Flutter⁷

• Dart Programming Tutorial - Full Course⁸

• Introduction to Dart for Beginners⁹

• Dart: Basics of Dart Part - 1/2 | Flutter¹⁰

[7]https://youtu.be/5rtujDjt50I?list=PLlxmoA0rQ-LyHW9voBdNo4gEEIh0SjG-q
[8]https://youtu.be/Ej_Pcr4uC2Q
[9]https://youtu.be/8F2uemqLwvE?list=PLJbE2Yu2zumDjfrfu8kisK9lQVcpMDDzZ
[10]https://youtu.be/DFRl4UyS7c8?list=PLR2qQy0Zxs_W4a6P70VYtzna7jwl3-lxI

對於那些不喜歡看視頻的人，能夠查看如下站點

• Tutorials¹¹

• Dart Programming Tutorial¹²

• Learn Dart In A Week With These Free Resources¹³

[11]https://dart.dev/tutorials
[12]https://www.tutorialspoint.com/dart_programming/index.htm
[13]https://hackernoon.com/learn-dart-in-a-week-with-these-free-resources-b892e5265220

是什麼使 Dart 如此典型，爲何 flutter 會使用它？

爲何 Flutter 使用 Dart？

能夠查看如下文章和視頻

• Why Flutter Uses Dart?¹⁴

• 視頻：Why Flutter Uses Dart?¹⁵

[14]https://hackernoon.com/why-flutter-uses-dart-dd635a054ebf
[15]https://youtu.be/5F-6n_2XWR8

Flutter 底層是如何工做的？

因爲 iOS 不容許動態編譯，所以您的 Dart 代碼會使用 AOT 直接編譯爲本地代碼。

要了解更多信息，請在下面查看這些資源：

• Technical overview¹⁶

• How to Dart and Flutter Work Together?¹⁷

• What's Revolutionary about Flutter¹⁸

• How Flutter reners Widgets¹⁹

• How is Flutter different for app development²⁰

[16]https://flutter.dev/docs/resources/technical-overview
[17]https://youtu.be/iVYpeEd3Jes
[18]https://hackernoon.com/whats-revolutionary-about-flutter-946915b09514
[19]https://youtu.be/996ZgFRENMs
[20]https://youtu.be/l-YO9CmaSUM

Flutter快速且易於使用，如今讓咱們看看如何安裝它。

如何安裝Flutter？

這是開發人員文檔的連接，您能夠在其中找到在現有的操做系統中安裝Flutter。

• Install²¹

[21]https://flutter.dev/docs/get-started/install

解決安裝過程當中的問題

若是您在安裝 flutter 時遇到任何問題，而且 flutter 沒法正常工做，那麼這就是出現了一些問題。

• 設置 flutter 路徑時遇到麻煩-找不到flutter命令²²

• Flutter Doctor沒法識別Android Studio flutter和dart插件，但已安裝插件²³

• Flutter和Dart插件未在Flutter Doctor中安裝警告²⁴

• 安裝 flutter 時的一些常見問題。²⁵

[22]https://stackoverflow.com/questions/49268297/having-trouble-setting-flutter-path-flutter-commands-not-found
[23]https://github.com/flutter/flutter/issues/21881
[24]https://github.com/flutter/flutter/issues/11940
[25]https://github.com/flutter/flutter/wiki/Workarounds-for-common-issues

設置Flutter的編輯器

• Set up an editor²⁶

[26]https://flutter.dev/docs/get-started/editor

建立您的Flutter項目

經過如下命令建立 flutter 項目

flutter create <project-name>
複製代碼

或者您能夠使用IDE（Intellij，Android Studio等）

項目概況

當您建立 flutter 應用程序時，您會看到這些文件和文件夾，大多數代碼是用 dart 編寫在 lib 文件夾中，native 代碼放在 android 和 ios 目錄下。

Jay Tillu的一篇文章解釋了該項目的結構。

• Flutter Project Structure²⁷

[27]https://dev.to/jay_tillu/flutter-project-structure-1lhe

運行你的第一個 App

• Test drive²⁸

或者你能夠使用如下命令來運行您的第一個應用程序

flutter run
複製代碼

當您啓動第一個應用程序時，必定會感到很興奮（從技術上說，這不是您的應用程序，代碼已經在那裏😜）。 我也很興奮🎉。

建立flutter應用程序時，您會看到計數器應用程序已經有代碼了。

運行代碼時，您將看到此信息。這是一個簡單的計數器應用程序，其中有一個FAB（FloatingActionButton）和 Text 來指示已按下 FAB 多少次。

[28]https://flutter.dev/docs/get-started/test-drive

flutter 中的 widget

若是看到代碼，您將看到 StatefulWidget 和 StatelessWidget。在深刻探討以前，咱們先來了解一下什麼是 Widget。

• Introduction to widget²⁹

基本上，在 flutter 應用程序中看到的全部內容都是一個小部件。

我發現 What is a Widget in Flutter³⁰ 一文中的解釋很是準確

Flutter小組還提供了一個YouTube播放列表（Widget of the week³¹），該列表僅討論flutter中的Widget。

[29]https://flutter.dev/docs/development/ui/widgets-intro
[30]https://stackoverflow.com/questions/50958238/what-is-a-widget-in-flutter
[31]https://youtu.be/b_sQ9bMltGU?list=PLjxrf2q8roU23XGwz3Km7sQZFTdB996iG

什麼是有狀態和無狀態小部件？

在 Stateless Widget 中，其全部屬性都是不可變的，這意味着 StatelessWidget 永遠不會自行重建（但能夠從外部事件重建），而 StatefulWidget 能夠。

• Intro to Flutter - Stateful and Stateless Widgets, Widget Tree - Part One³²

• Flutter: Stateful vs Stateless Widget³³

• How to Create Stateless Widgets - Flutter Widgets 101 Ep. 1³⁴

• How Stateful Widgets Are Used Best - Flutter Widgets 101 Ep. 2³⁵

• Google's Flutter Tutorials | 6 - Stateless & Stateful Widgets | Android & iOS | Dart³⁶

[32]https://youtu.be/-QRQIKtPTlI
[33]https://medium.com/flutter-community/flutter-stateful-vs-stateless-db325309deae
[34]https://www.youtube.com/watch?v=wE7khGHVkYY&feature=emb_title
[35]https://www.youtube.com/watch?v=AqCMFXEmf3w&feature=emb_title
[36]https://www.youtube.com/watch?list=PLR2qQy0Zxs_UdqAcaipPR3CG1Ly57UlhV&v=VnWHOogtDk8&feature=emb_title

讓咱們建立第一個Flutter應用

Google已經提供了一個 Codelab，您能夠從那裏開始學習如何構建本身的第一個 Flutter 應用程序。

• Write Your First Flutter App, part 1³⁷

• Write Your First Flutter App, part 2³⁸

• Flutter Tutorial Part 1: Build a Flutter app from scratch³⁹

• 1.3 Flutter Hello World Tutorial: Create First Flutter Application: Flutter Dart Tutorial⁴⁰

• 1.4 First Flutter Application using Dart: PART-2 Flutter Tutorial for Beginners using Dart⁴¹

[37]https://codelabs.developers.google.com/codelabs/first-flutter-app-pt1/#4
[38]https://codelabs.developers.google.com/codelabs/first-flutter-app-pt2/#0
[39]https://medium.com/aviabird/flutter-tutorial-how-to-build-an-app-from-scratch-b88d4e0e10d7
[40]https://www.youtube.com/watch?list=PLlxmoA0rQ-Lw6tAs2fGFuXGP13-dWdKsB&v=dsyucuytW2k
[41]https://www.youtube.com/watch?list=PLlxmoA0rQ-Lw6tAs2fGFuXGP13-dWdKsB&v=ycHX8QtV08c

如何在 Flutter 中建立 UI？

爲了使 UI 更加流暢，您須要基本瞭解佈局以及如何使用它們。

• Layouts in Flutter⁴²

• Flutter layout Cheat Sheet⁴³

[42]https://flutter.dev/docs/development/ui/layout
[43]https://medium.com/flutter-community/flutter-layout-cheat-sheet-5363348d037e

如何在您的應用中添加交互？

在 flutter 中，您不能只是分配一個值並留下它

例如

String value="Hello";
------------------------------
Text(value);
---SOMEWHERE IN THE CODE------
onTap(){
value="How are you?";
}
複製代碼

若是您認爲文本將要更改，那麼您錯了🙅‍♂️，您將不得不使用 setState()。

onTap(){
	setState({
		value="How are you?";
	});
}
複製代碼

添加 setState() 將重建小部件並顯示更改。

• Adding interactivity to your Flutter app⁴⁴

我建議您跟進有關開發的 Flutter 官方文檔

• Development⁴⁵

flutter 中的全部內容都是小部件，您能夠自行建立任何自定義小部件，可是已經有經過 flutter 定義的小部件。

• Widget catalog⁴⁶

[44]https://flutter.dev/docs/development/ui/interactive
[45]https://flutter.dev/docs/development
[46]https://flutter.dev/docs/development/ui/widgets

Flutter 中的 JSON 解析

• JSON and serialization⁴⁷

• Parsing JSON in Flutter⁴⁸

• Parsing complex JSON in Flutter⁴⁹

• Working with APIs in Flutter⁵⁰

• Handling Network Calls like a Pro in Flutter⁵¹

• Flutter - Build An App To Fetch Data Online Using HTTP GET | Android & iOS⁵²

• Testing, JSON serialization, and immutables (The Boring Flutter Development Show, Ep. 2)⁵³

[47]https://flutter.dev/docs/development/data-and-backend/json
[48]https://medium.com/flutterdevs/parsing-complex-json-in-flutter-b7f991611d3e
[49]https://medium.com/flutter-community/parsing-complex-json-in-flutter-747c46655f51
[50]https://medium.com/flutter-community/working-with-apis-in-flutter-8745968103e9
[51]https://medium.com/flutter-community/handling-network-calls-like-a-pro-in-flutter-31bd30c86be1
[52]https://www.youtube.com/watch?list=PLR2qQy0Zxs_UdqAcaipPR3CG1Ly57UlhV&v=aIJU68Phi1w
[53]https://www.youtube.com/watch?v=TiCA0CEePyE

在 Flutter 中使用數據庫

SQLite

• Persist data with SQLite⁵⁴

• Data Persistence with SQLite | Flutter⁵⁵

• 4.1 Flutter SQFLite Database Tutorial: Implement SQLite database with example: Section Overview⁵⁶

• Moor (Room for Flutter) #1 – Tables & Queries – Fluent SQLite Database⁵⁷

[54]https://flutter.dev/docs/cookbook/persistence/sqlite
[55]https://medium.com/flutterdevs/data-persistence-with-sqlite-flutter-47a6f67b973f
[56]https://www.youtube.com/watch?list=PLDQl6gZtjvFu5l20K5KTEBLCjfRjHowLj&v=1BwjNEKD8g8
[57]https://www.youtube.com/watch?v=zpWsedYMczM

SharedPreferences

• Shared preferences plugin⁵⁸

• Using SharedPreferences in Flutter⁵⁹

• Store key-value data on disk⁶⁰

• Making use of Shared Preferences, Flex Widgets and Dismissibles with Dart's Flutter framework⁶¹

[58]https://pub.dev/packages/shared_preferences
[59]https://medium.com/flutterdevs/using-sharedpreferences-in-flutter-251755f07127
[60]https://flutter.dev/docs/cookbook/persistence/key-value
[61]https://www.youtube.com/watch?v=IvrAAMQnj4k

使用Firebase

• 將 Firebase 添加到您的 Flutter 應用⁶²

• Firebase for Flutter⁶³

• Flutter - Firestore introduction⁶⁴

[62]https://firebase.google.com/docs/flutter/setup
[63]https://codelabs.developers.google.com/codelabs/flutter-firebase/#0
[64]https://www.youtube.com/watch?list=PLgGjX33Qsw-Ha_8ks9im86sLIihimuYrr&v=LzEbpALmRlc

其餘學習 Flutter 的資源

如下是其餘開發人員和Flutter團隊提供的一些資源：

• Technical overview⁶⁵

• Resources to learn Flutter⁶⁶

• Free resources to learn and advance in Flutter⁶⁷

• Flutter Community⁶⁸

• My Favourite List of Flutter Resources⁶⁹

• awesome-flutter⁷⁰

• londonappbrewery/Flutter-Course-Resources⁷¹

• A Searchable List of Flutter Resources⁷²

• FlutterDevs⁷³

[65]https://flutter.dev/docs/resources/technical-overview
[66]https://medium.com/flutter-community/resources-to-learn-flutter-2ade7aa73305
[67]https://medium.com/flutter-community/free-resources-to-learn-and-advance-in-flutter-e07875ffc825
[68]https://medium.com/flutter-community
[69]https://medium.com/coding-with-flutter/my-favourite-list-of-flutter-resources-523adc611cbe
[70]https://github.com/Solido/awesome-flutter
[71]https://github.com/londonappbrewery/Flutter-Course-Resources
[72]https://flutterx.com/
[73]https://medium.com/flutterdevs

關於 Flutter 的問題

• FAQ⁷⁴

• Answering Questions on Flutter App Development⁷⁵

• Flutter Vs. React Native: FAQs for Every Developer⁷⁶

[74]https://flutter.dev/docs/resources/faq
[75]https://medium.com/@dev.n/answering-questions-on-flutter-app-development-6d50eb7223f3
[76]https://hackernoon.com/flutter-vs-react-native-faqs-for-every-developer-yjp329z

本文僅適用於初學者。