Mark Clow - Learn Google Flutter Fast: 65 Example Apps

State & ScopedModel Approach The purpose of this chapter is to introduce the purpose of this book and acknowledge those people who have made this book possible. This chapter also contains a disclaimer and revision history, along with information on how to get to the source code for the examples. First and foremost, thanks to my wife Jill and her patience. I hope she is enjoying herself doing her favorite things like Paddle boarding, Kayaking and being at one with nature. I hope she never reads this book because it would bore her. I would also like to acknowledge the amazing work done by the Google engineers.

When I ran the profiler and saw just how fast the UI was redrawing, I was blown-away. Google has some amazing talent, what a team of engineers.

I wrote this book to broaden my own knowledge of this technology and I still have a way to go. However, I learnt a lot in writing this book and I hope it helps others. Work I have to be honest; I also wrote this book for some self-promotion. After this book is published, I intend to continue working on apps for my wifes business and find some part-time Flutter work.

If you are interested, shoot me an email at .

Lets get this over with as quickly as possible. Some of this information in this book may be incorrect (I am a human being that makes mistakes) and that this publication is somewhat opinionated. I am trying my best to be as technically accurate as possible, but I am still learning a lot and have much to learn about Flutter and Dart. I have opinions but please dont take them too seriously. This book has taken a long time to write and I will continue to improve it whenever I have time, adding more content when possible. This book has taken a long time to write and I will continue to improve it whenever I have time, adding more content when possible.

So, if you get an earlier version of the book it may be slightly less complete than later on. If this is the case, email me a proof of purchase at and I will send you a PDF version, which will be watermarked with your name (sorry but its to prevent copying). I welcome (constructive) criticism and input so if you have any, please email me at markclow@hotmail.com.

Date	Description
3/31/2019	Initial version.
4/7/2019	Added chapter name to footer. Applied corrections from printed proof notes many! Simplified chapters re setup. Added Animations Chapter. Added Dismissible Widget.
4/25/2019	Adding more content to Stack.
4/29/2019	Fixes for missing images on Kindle.
5/12/2019	Isolates.
5/20/2019	Channels.
5/23/2019	ConstrainedBox.
6/15/2019	How to Clean & Reimport Your Packages
6/19/2019	Application Icons.
6/20/2019	Publishing Your Android App.
6/21/2019	Publishing Your iOS App.
6/28/2019	Apple Guidelines.
7/2/2019	Flutter commands.
7/28/2019	Flutter folders and files.
7/28/2019	Flutter folders and files. Event handlers.
8/11/2019	Lambda functions. Native compilation on platforms. UI as code. Named parameters.
8/18/2019	Final variables.
8/18/2019	Final variables. Borders, padding & margin.

Location This book has many examples & exercises. The source code is available here: https://github.com/markclow/flutter_book_examples Example & Exercise Names Each example or exercise should have a name in quotes (see the example below in the box). The name in quotes is the directory in which the source code is located. This is the format: Example gesture_app One File Another thing to bear in mind is that the exercises have all been written to use a single file. This was so that there could be one single continuous listing in the book.

In reality, you would obviously split your project up into many smaller files.

The purpose of this chapter is to give the reader a quick introduction to the world of Mobile Application development, and to introduce him or her the problem of cross-platform development, and how it was approached by different companies. Before we go into this, lets introduce some of the terminology first. Compiler A computer program consists of a set of instructions for the computer to perform a specific task. Most computer programs are written using high-level programming languages. Thus, the computer does not understand these programs.

Therefore, they are converted to machine understandable, machine language. A compiler is a software that performs this conversion. It converts the source program into machine language. Native and Non-Native Compilers A native compiler converts the source program into machine code for the platform on which it runs. The code will not require any translation to be interpreted and executed by the CPU. A non-native compiler converts the source program into a more general format where it can be run on multiple platforms.

The code will require translation to be interpreted and executed by the CPU.

Mobile Applications A mobile application (shortened to mobile app) is a computer program or software application designed to run on a mobile device such as a phone/tablet or watch. Writing mobile apps sounds easy but is complicated by the number of platforms that are available. Your app could run on an iPhone, it could run on an iPad, it could run on an Android Phone etc. Also remember that these platforms could change quickly as new devices appear on the market. Before Cross-Platform Mobile Application Development In the past, in order to produce performant applications, developers had to write the application code specifically for each platform, writing what is called native apps.

There would often be one codebase (and developers) for iOS (iPhone) and another codebase (and developers) for Android. For native iOS, Objective-C and Swift are the preferred programming languages. For native Android, Java and Kotlin are the preferred languages. This complicated matters:

• You had to have developers with multiple skillsets.

  • Expensive.
• Sometimes the app for one platform would look very different from the other platforms.
Early Cross-Platform Development Tools Anyway, Silicon Valley soon realized what a problem this was and set to work on developing tools for cross-platform mobile application development. They quickly split into two groups of development tools: those that used native libraries and those that didnt.

Development Tools That Used Native Libraries These tools created a Unified API on top of the native SDK supplied by Apple and Google. Many of these development tools, for example Xamarin, Appcelerator, Nativescript are still around. Unified API Does Not Cover 100% The problem with these types of applications is that the Unified API does not cover 100% and leaves the developers with many burdens, such as having to still write a large chunk of platform-specific code. Use Widget SDKs Also, these apps use the Widgets from the SDKs. Therefore, the apps can look different because they use different Widgets from different SDKs for different platforms. Here is an example of how different button Widgets are used for different platforms: