This chapter gets you started building apps. It presents the key elements of App Inventor, the Component Designer and the Blocks Editor, and leads you through the basic steps of creating your first app, HelloPurr. When you’re finished, you’ll be ready to build apps on your own.
Figure 1-1. The HelloPurr app
A typical first program with a new computer system prints the message “Hello World” to show that everything is connected correctly. This tradition goes back to the 1970s and Brian Kernighan’s work on the C programming language at Bell Labs. With App Inventor, even the simplest apps do more than just show messages: they play sounds and react when you touch the device. So, we’re going to get started right away with something more exciting: your first app (as shown in Figure 1-1) will be “HelloPurr,” a picture of a cat that meows when you touch it and purrs when you shake the device on which it’s being viewed.
What You’ll Learn
The chapter covers the following topics:
Building apps by selecting components and specifying their behavior.
Using the Component Designer to select components. Some components are visible on the device’s screen and some aren’t.
Adding media (sounds and images) to apps by uploading them from your computer.
Using the Blocks Editor to assemble blocks that define the components’ behavior.
Testing apps with App Inventor’s live testing ...
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