Finger+Painting




 * This lesson will cover**
 * The App Inventor environment
 * Components
 * Properties
 * Code (blocks)
 * Event-driven programming
 * Variables


 * Mobile features**
 * Touch interface
 * Graphics
 * Camera
 * Accelerometer


 * Design**
 * App Inventor Task Resources**




 * Algorithm and code**

Look at the document below for the algorithm and code.



A **bug** is an error which stops your code working as expected. There are **two** main types of bug which can occur in a program:
 * Bugs[[image:http://cdn4.iconfinder.com/data/icons/meBaze-Freebies/128/close-bug.png width="101" height="73" align="right"]]**

This happens when the rules of the language have been broken, e.g. by mis-spelling a command. Syntax errors usually stop the code from running. Languages like App Inventor provide code in ready-written blocks, so you won’t make many syntax errors.
 * Syntax error**

This means your code runs, but doesn’t do what you expect. Unfortunately, it’s still possible to make logic errors in App Inventor! Finding and fixing these errors in a program is known as **debugging**.
 * Logic error**

Task 2 The code we have created so far has a bug:

The starting colour of the “paint” is black. Once you select another colour, there is no way to get back to black. Try adding another button to enable the user to use the colour black.

Extention 1

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