Timer Events and Animation

An app is a set of event handlers. When something occurs, perform some instructions (blocks).

Event Types

UI events

• when Button.Click
• when Canvas.Touched, when Canvas.Dragged

External Events

• when Texting.MessageReceived
• info from web, GPS sensors

Now we'll consider timer events, i.e., when you want something to happen as time passes. A Clock component is used.

Clock properties

• timerInterval -- default is 1000 (ms)
• timerEnabled -- default is true, meaning Timer event will trigger every timerInterval

Image sprites

Within a canvas, you can place an ImageSprite or Ball. They only "live" within a Canvas. Ball and ImageSprite have the same behavior. ImageSprite is different in that you can specify an image file for it.

Instructor demo: A sprite that moves back and forth across the screen

1. Move sprite one second after a button is clicked
2. Move sprite back and forth continuously after button is clicked (alternatively when app begins)