Android How to Program

9. Doodlz App

Objectives

In this chapter you’ll:

• Detect when the user touches the screen, moves a finger across the screen and removes a finger from the screen.

• Process multiple screen touches so the user can draw with multiple fingers at once.

• Use a SensorManager to detect accelerometer motion events to clear the screen when the user shakes the device.

• Use an AtomicBoolean object to allow multiple threads to access a boolean value in a thread-safe manner.

• Use a Paint object to specify the color and width of a line.

• Use Path objects to store each line’s data as the user draws the lines and to draw those lines with a Canvas.

• Use a Toast to briefly display a message on the screen.

Outline

9.1 Introduction

9.2 Test-Driving the Doodlz ...