ACS-1805 Introduction to Programming
1805 introduces students to programming using technology for
creating programs that run on Android devices.
Android:
• operating system for smart phones and tablet computers
• based on Linux
• developed by Google in conjunction with the Open Handset
Alliance
• Apps can be created using Java, App Inventor and other
environments
• Apps are run in the Dalvik virtual machine
Chapter 1. Hello Purr (Introduction to programming with AI)
Demonstration: building an app with App Inventor , pages 1-10
1. We will build the Hello Purr app in class
2. This is a simple app that displays two things on the screen
a) An instruction to the user to ‘pet’ the kitty
b) A picture of a kitty
3. When the app is running on an Android device (emulator,
phone, or tablet computer), the user will ‘touch’ the kitty and
the kitty will meow
4. For this app the programmer determines two things: what
appears on the screen, and what behaviour is required.
Chapter 1. Hello Purr
Demonstration: building an app with App Inventor, pages 1-10
1. Starting app inventor in a browser
beta.appinventor.mit.edu
2. Create a new project (app)
3. Create the user interface (the screen’s appearance)
a) A button with a picture
b) A label with text giving the user directions to follow
c) A sound to be made by the kitty (?)
4. Start the blocks editor
a) Define the behaviour for components. That is, write the code
for when the user clicks the button …
5. Running the app in the emulator
Chapter 1. Hello Purr
Introduction to building apps with App Inventor, pages 1-10
1. Optional: David Wolber’s youtube videos
http://www.youtube.com/watch?v=Fu8zwNQt5XE&list=PLCF
2969C390CE87F4
2. Lots of other videos exist on youtube and elsewhere
Chapter 1. Hello Purr
Summary, pages 1-10
The App Inventor Programming environment has 3 major
components:
1.
Component Designer. This comprises several areas:
a) Palette. The Palette itself has several sub-palettes.
b) Viewer – shows a rough view of your app’s screen (user
interface)
c) Components List – a list of your app’s components (visible & nonvisible)
d) Properties – shows the properties of the current component
selected in the List.
e) Media – shows the sounds and images of your app
Chapter 1. Hello Purr
Summary
2.
Blocks editor (this happens to be a program written in Java)
a) facilitates creating program blocks that describe and control
behaviour within the app. Our example has a When Button is
Clicked block.
3.
Android emulator –emulates an Android phone
Chapter 1. Hello Purr
Page 11+ Optional
Page 11: Adding a Purr
1.
An additional operation is specified for the When Button is Clicked
event occurs – Sound1.vibrate executes.
Page 13: Shaking the Phone
1.
2.
The phone emulated by App Inventor has an accelerometer sensor
(detects motion).
Motion can be detected using a When Accelerometer is Shaking
event block. Of course, this requires an AccelerometerSensor
component.
Page 14: Downloading an app to a phone or tablet