Alice in Action with Java Chapter 1 Getting Started with Alice

Objectives Design a simple Alice program Build a simple Alice program Animate Alice objects by sending them messages Use the Alice doInOrder and doTogether controls Alice in Action with Java

Objectives (continued) Change an object’s properties from within a program Use Alice’s quad view to position objects near one another Alice in Action with Java

Getting and Running Alice Alice software is freely distributed Downloading Alice Go to the website: http://alice.org Click the link Get Alice 2.0 Click download link specific to your operating system Save Alice.zip (or Alice.dmg) to your PC Installing and running Alice Extract Alice from Alice.zip (or Alice.dmg) file Create desktop shortcut (alias) to Alice.exe Double-click Alice icon to launch Alice application Alice in Action with Java

The Alice Tutorials Four interactive tutorials teach the basics of Alice Work through tutorials before continuing in chapter Access tutorials from Tutorial tab of startup dialog Developing programs involves art and science Active learning: implementing designs as you read Alice in Action with Java

The Alice Tutorials (continued) Alice in Action with Java

Program Design Programming in Alice is similar to filmmaking Filmmaking terms Treatment: short prose version of a film Screenplay: written version of film that includes dialog Scene: a piece of the story usually set in one location Shot: part of scene told with camera in one position Viewpoint: perspective of camera for a given shot Storyboard: drawing that provides blueprint for a shot Alice in Action with Java

User Stories Prose versions of programs from user perspective Critical components of a user story A basic description of events taking place in the story Nouns in the story (which correspond to objects) Verbs in the story (which correspond to actions) Chronological flow of actions (algorithm) User story is the foundation of good software The user story plays a role similar to a screenplay Guideline: number actions according to their flow Alice in Action with Java

User Stories (continued) Alice in Action with Java

Storyboard-Sketches Storyboard Detailed drawing of a shot Arrows show movements of characters or camera Collection of storyboards helps actors visualize film Storyboard-sketch: storyboard for application screen Components of a storyboard-sketch: Object’s position (location) Object’s pose (position of limbs, if it has any) Object’s orientation (direction it is facing) Camera’s viewpoint Alice in Action with Java

Storyboard-Sketches (continued) Alice in Action with Java

Transition Diagrams Link the multiple storyboard-sketches In a movie, transition diagram is a linear sequence Alice in Action with Java

Transition Diagrams (continued) Alice in Action with Java

Programming Implementation in Alice Templates provide a basic world environment Sample program is based on the “grass” Template Areas in the Alice window Menus: includes File, Edit, Tools, and Help Buttons: includes Play, Undo, and Redo Object tree: lists all world objects; e.g., ground Details area: includes properties, methods, functions World window: displays graphic objects in a program Editing area: includes editing space and controls Events area: contains actions responding to events Alice in Action with Java

Programming Implementation in Alice (continued) Alice in Action with Java

Program Style Change program display styles in Preferences How to access Preferences dialog box Click the Edit menu Click the Preferences choice Selecting a display style in Preferences dialog Click next to “display my program” in General tab Select a style Style recommended for course: Java Style in Color Alice in Action with Java

Program Style (continued) Alice in Action with Java

Adding Objects to Alice Class: blueprint for an object How to populate Alice world with objects Click Add Objects button in world window Locate class specifying the object in the Alice Gallery Right-click class and select “Add instance to world” Objects in sample world: aliceLiddell and whiteRabbit Naming conventions for objects and classes Class: capitalize all words; e.g., AliceLiddell Object: capitalize all but first word; e.g., aliceLiddell Objects can be renamed from the object tree Alice in Action with Java

Adding Objects to Alice (continued) Alice in Action with Java

Accessing Object Subparts Bounding box: encloses any Alice object Impact of selecting an object in the object tree Bounding box is drawn around object in world window Details area adapts to the selected object First action to program: Alice turns head to user First set of programming steps Select + sign next to aliceLiddell in object tree Select + sign next to neck subpart Select head (bounding box is drawn, details change) Drag doInOrder control to top of editing window Alice in Action with Java

Accessing Object Subparts (continued) Alice in Action with Java

Accessing Object Subparts (continued) Alice in Action with Java

Sending Messages Programs rely on sending messages to objects Method: behavior-producing message Programming Alice’s head to turn Select Alice Liddell’s head in the object tree Scan through the methods in the details area Click on pointAt() Drag pointAt()to the editing area and drop it Specify camera as the target Alice in Action with Java

Sending Messages (continued) Alice in Action with Java

Testing and Debugging Bug: error interfering with normal program functions Debugging: process of removing program bugs Click the Play button to test Alice Liddell application Alice Liddell’s head will turn toward the user Alice in Action with Java

Testing and Debugging (continued) Alice in Action with Java

Coding the Other Actions say() message Displays dialog for an object Text can be customized by selecting other… Task: complete first Alice Liddell application Add Alice Liddell’s initial greeting Point the white rabbit to the user Have Alice Liddell introduce herself Have the white rabbit introduce himself Customize messages by selecting from more… Example: adjust fontSize of message text to 30 Alice in Action with Java

Coding the Other Actions (continued) Alice in Action with Java

Statements Statement: a line or control structure in a program Computer program is a collection of statements Basic format of a line in a program object.message(value); more... Control structures manage other statements Example: doInOrder contains other statements Alice in Action with Java

The Final Action Sequential execution Simultaneous execution Actions are performed consecutively Example: actions executed in doInOrder structures Simultaneous execution Actions are performed in parallel Example: actions performed in doTogether structure Finishing the first program Add doTogether control structure to application Send say( )to aliceLiddell and whiteRabbit Message value: Welcome to our world Alice in Action with Java

The Final Action (continued) Alice in Action with Java

Final Testing First set of actions are performed separately Final actions are performed simultaneously Alice in Action with Java

Final Testing (continued) Alice in Action with Java

The Software Engineering Process A methodical approach to constructing programs Two parts: design and implementation and testing Elements of software design Write the user story Organize nouns and verbs into an algorithm Create storyboard-sketches and the transition diagram Elements of software implementation and testing For each noun in the story, add an object to Alice world Match message to verb and send message to object Test message to determine if it produces desired action Alice in Action with Java

Alice’s Details Area Reflects attributes and behaviors of selected object Three panes: properties, methods, and functions Alice in Action with Java

The properties Pane Includes attributes such as color, opacity, visibility Change values to alter object appearance/behavior Example: make the White Rabbit disappear Click opacity in the properties pane Drag opacity to the editing area Set opacity to 0 Change the duration to 2 seconds How a program changes when a property is altered New message is added to editing area In the example above, a set () message is added Alice in Action with Java

The properties Pane (continued) Alice in Action with Java

The methods Pane Provides a list of behavior-generating messages Objects respond to set of predefined basic messages Example: the resize( ) message Some classes provide advanced methods Examples: Frog, Monkey, Penguin You can build complex animations using methods Alice in Action with Java

The methods Pane Alice in Action with Java

The functions Pane Provides list of information returning messages Differentiate functions from methods Functions return data, messages produce behavior Type of information returned by functions Proximity to another object Size in terms of height, width, or depth Spatial relation to another object Point of view (position and orientation in the world) Subparts world object responds to different set of functions Alice in Action with Java

The functions Pane (continued) Alice in Action with Java

Alice Tip: Positioning Objects Using Quad View Actions performed after pressing ADD OBJECTS Navigate the Alice Gallery Locate classes Use classes to add objects to the world Two views: single view and quad view quad view World window View from the top View from the right View from the front Alice in Action with Java

Alice Tip: Positioning Objects Using Quad View (continued) Alice in Action with Java

Summary Alice: software tool used to create virtual worlds User story: prose description of program form the user’s point of view Shot: component of a scene with the camera at one viewpoint Algorithm: flow of actions that solves a problem Storyboard-sketch: drawing of a distinct screen in a computer application Alice in Action with Java

Summary (continued) Alice window: menus, buttons, object tree, details area, world window, editing area, and events area Class: blueprint for an object Method: behavior-producing message Function: message that returns information Software engineering encompasses software design, and implementation and testing Alice in Action with Java