Chapter 5 Interactive Programming

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Chapter 5 Interactive Programming

• Dr Wayne Machuca
• MHCC

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Objects Inheritance

• Recall that when you instantiate an object, the
  new object inherits from the class
• Design
• Properties
• Values
• And Methods
• Methods are things that the object does or can do

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Events

• Events are things that cause a method to run
• Press a key
• Hit Enter
• Click a mouse button
• These are external influences that have an effect
  on a program.
• Can you think of any others?

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Event Handling Method

• What do you want to have happen when a particular
  event occurs?
• Many software have event handling methods
• Visual Basic .NET
• Java
• HTML ltformgt
• And more

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Think like this
What EVENToccurred?
Space Bar was selected
Execute
Click event method
Space Barevent method
Letter Pevent method
Enter event method
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Flight Simulator
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Flight Simulator

• Create a simple grass world
• Add a biplane and some buildings
• Dont get fancy---yet!

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StoryboardflyForward

• Do together
• Biplane move forward 2 meters,duration 2.4
  sec,style abruptly
• Play biplane engine sound

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Story Boardbarrel

• Event Spacebar press
• Response
• Do Together
• Roll biplane full revolution
• Play biplane engine sound

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Now link the events to methods

• When the world starts is an event
• Alice creates this link automatically

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We will create 2 new events

• When the Up Arrow is selected, flyForward
• When the Spacebar is selected, barrel

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Create new event
2. Select
1. Select
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Now add the barrel event
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Listening

• Events are world-level
• Alice listens for an event to happenand the
  causes an action (method)appropriate to the
  event
• Java (for example) also uses an event listener
  when then directs the action

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Firetruck
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Firetruck program

• In this program you will create a grass world
• Add burningBuilding
• Add firetruck
• Add 2 girls and 1 random guy
• Place the people in the different windows

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It should look something like this
People
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Storyboard

• EventClick on a person
• ParameterswhichFloor, whichPerson, howFar
• Methodpoint ladder at whichFloorextend ladder
  howFarwhichPerson slides down the ladderladder
  contracts howFar

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Now create a new methodwith variables
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Now create the method savePerson
This is a composite image
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Now Create the Events
This is a composite image
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Now lets try something a little harder

• Greek Tragedy

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Storyline

• The scene is a Grecian stage
• Zeus (a god) stands on a cloud above the stage.
  Various characters stand on the stage.
• When a character is selected
• Zeus turns to face that character
• Zaps them with a lightening bolt
• Special effects

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Event

• Eventobject is mouse clicked
• Event handlershootBolt
• Parameterwho (the object that was clicked)
• ActionDo in order
• Call prepareToShoot, who is target
• Call lighteningAndThunder
• Lightening move to clouds position.