Skip to Content
App Inventor 2, 2nd Edition
book

App Inventor 2, 2nd Edition

by David Wolber, Hal Abelson, Ellen Spertus, Liz Looney
October 2014
Beginner to intermediate
360 pages
9h 3m
English
O'Reilly Media, Inc.
Content preview from App Inventor 2, 2nd Edition

Chapter 18. Programming Your App to Make Decisions: Conditional Blocks

Figure 18-0.
Programming Your App to Make Decisions

Computers, even small ones like the phone in your pocket, are good at performing millions of operations in a single second. Even more impressively, they can also make decisions based on the data in their memory banks and logic specified by the programmer. This decision-making capability is probably the key ingredient of what people think of as artificial intelligence, and it’s definitely a very important part of creating smart, interesting apps! In this chapter, we’ll explore how to build this decision-making logic into your apps.

An event handler that tests for a condition and branches accordingly
Figure 18-1. An event handler that tests for a condition and branches accordingly

Chapter 14 discusses how an app’s behavior is defined by a set of event handlers. Each event handler executes specific functions in response to a particular event. The response need not be a linear sequence of functions, however; you can specify that some functions be performed only under certain conditions. For example, a game app might check if a player’s score has reached 100, or a location-aware app might ask if the phone is within the boundaries of some building. Your app can ask such questions and, depending on the answer, proceed accordingly.

Consider the diagram in Figure 18-1

Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.

Read now

Unlock full access

More than 5,000 organizations count on O’Reilly

AirBnbBlueOriginElectronic ArtsHomeDepotNasdaqRakutenTata Consultancy Services

QuotationMarkO’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.
Julian F.
Head of Cybersecurity
QuotationMarkI wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.
Addison B.
Field Engineer
QuotationMarkI’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.
Amir M.
Data Platform Tech Lead
QuotationMarkI'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
Mark W.
Embedded Software Engineer

You might also like

App Inventor

App Inventor

David Wolber, Hal Abelson, Ellen Spertus, Liz Looney
App Inventor 2 Essentials

App Inventor 2 Essentials

Felicia Kamriani, Krishnendu Roy
Hello App Inventor!

Hello App Inventor!

Paula Beer, Carl Simmons

Publisher Resources

ISBN: 9781491907214Errata Page