Preface

Almost everyone has had an idea for an app or perhaps declared, "I wish there were an app for that!" But until recently, taking an idea and building it into a fully functional app would have required hiring an expert software programmer and paying thousands and thousands of dollars. The world of mobile app development had been the domain of an elite group of people with highly specialized skills—proficient coders. The App Inventor project sought to change this reality by democratizing software development. App Inventor 2 is a free, blocks-based, drag-and-drop visual programming language that makes it possible for anyone, even people with no prior coding experience, to turn an idea into a fully functional Android app.

As educators, our passion for promoting global education and empowering people to move from being users of technology to becoming creators of technology were the inspirations for writing this book. With App Inventor, a 12-year-old, a speech therapist, a baseball coach, or anyone else for that matter, can develop an app that is personal, meaningful, and useful to them. People from all backgrounds and levels of education can develop a digital solution to a problem they see in their community. Any App Inventor app, such as an educational game, a music tutorial, or a garbage recycling program can be published or sold in app markets, and thus, have a global impact or spurn opportunities for entrepreneurship, collaboration, and community building.

App Inventor offers an alternative entry point to Computer Science that is more user-friendly and less intimidating than traditional cryptic white-text-on-a-black-screen programming. The colorful blocks that snap together like puzzle pieces along with a design tools enable users to learn both coding and user experience design skills. Furthermore, with a wide gender gap in computer science—males dominating both classes and jobs—we are also passionate about using App Inventor to introduce more girls and women to mobile computing opportunities, such as app contests with Technovation (www.technovationchallenge.org) and coding clubs with Girls Who Code (www.girlswhocode.com).

Because you can take any idea and turn it into a mobile app, the opportunities for imagination, creativity, and innovation are indeed endless. The purpose of this book is to help spark such creativity while introducing you to basic computer science principles, computational thinking, and programming. This book teaches you to navigate the App Inventor platform and helps you become familiar with its features through step-by-step tutorials on building three different mobile apps. Throughout the book, we offer design tools and tips as a pathway to user experience design, since the user interface is such an integral part of any mobile app. Ultimately, by the end of this book, you will be equipped with enough skills to embark on developing your own mobile app from scratch. We are excited to see the apps you are inspired to create and hope that you will share them with us.

We are so excited to share our passion for mobile app development with you and hope that this book awakens a creative spark to make technology that is personal, meaningful, and useful to you. We are thankful to Hal Abelson, Mark Friedman, and all of the original App Inventor developers and visionaries who created the platform that has evolved into App Inventor 2. We are proud to be furthering the App Inventor mission and encourage all of you budding software programmers to, in turn, share App Inventor with other noncoders. Together we can empower others to become part of a growing movement to connect and impact the world with digital creativity.