1. Variables, operators, canvas, and multimedia
Dr. José M. Reyes Álamo

2. Outline
Variables
Operators
Canvas

3. Variables

4. Properties and variables
In general the memory is a set of cells or slots, like spread sheet, where we store data.
Properties and variables are named memory slots
What is the difference?
We use variables and properties to store information used within our app.

5. An example Variable definition Name the variable cost=0
Assign initial value
Using the variable within an event handler
Set a value
Get the value
cost=0
profit=0
price=0
On Button1.Click
cost=7
profit=5
price=cost + profit
Label1.text = price
In class create an application that executes an arithmetic operation with two numbers
Something like this
cost=0
profit=0
price=0
On Button1.Click
cost=7
profit=5
prices=cost + profit
Label1.text = price
You can extend it to calculate salesPrice adding 0.07 of taxes or something like that
Also create a better interface.

6. Variables on AppInventor
Numeric Variables:

7. Operators

9. Reference Arithmetic operators and other math blocks Logic operators
Logic operators

10. Canvas

11. Canvas is a pixels grid
Reference: basic.html#Canvas 1 2 3 4

12. OpenLab and Blackboard
Check OpenLab for any new lab.
Check Blackboard for any new quiz.
Project:
Brainstorm an idea
Get professor's approval
Post your idea in your portfolio
Must work in teams of 2 or 3
It must be an app and the topic is open: a game, a tool, an enhanced version of a previous app