Display Programming

Display Programming

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  Sudha Hariharan
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  Display Programming -Allows you to work with elements that appear on the Stage of Adobe Flash Player and Adobe Air. Display List – a hierarchy of displayed objects (visible objects) that are contained in applications built in Action Script 3.0
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  Stage Stage isthe base container of display objects. Every application has one stage object that contains all the on-screen display objects. Stage is the top level object in the display hierarchy. When a SWF File is run using Flash Player the following steps occur Flash player calls the constructor function of the main class of the SWF file. The main class always extends the Sprite class. The instance of the main file is created. This instance is always of the type display object. The instance is added as a child to the Stage Object. From any DisplayObject instance, one can access the Stage through its stage property.
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  Display Objects Anyelements that appear on the screen in an application are of type DisplayObject. DisplayObject class can be found in flash.display package. Subclasses of DisplayObject include vector shapes, movie clips, text fields etc. Common subclasses that are used frequently are Sprite, Shape, Bitmap and MovieClip.
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  Display Object ContainersDisplay object Containers are display objects with a special feature that they can also contain their own child objects. It is a subclass of DisplayObject class. It can include multiple child display objects in its child list.
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  Classes contained inflash.display package. Bitmap - used to define bitmap objects, create bitmap objects, and alter bitmaps. Loader - used to load external assets. Shape - used to create vector classes such as rectangles, lines, circles, etc. SimpleButton – it is an ActionScript representation of a Flash button symbol. Sprite – can contain objects of its own and also other child display objects. MovieClip – it is an ActionScript representation of a movie clip symbol created in Flash authoring. It is similar to Sprite object except that it has a timeline.
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  Classes that arenot a part of flash.display package TextField – it is included in the flash.text package. It is used for text display and input. Video – it is included in the flash.media package. It is used for displaying video
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  Display objects andmany of its subclasses are in reality Abstract classes. These classes serve as parent classes for other display objects, combining common functionality into a single class. Hence instances of these classes cannot be created. Some of the common subclasses of Display Object that are also abstract are AVMMovie1 – used to represent loaded SWF files that are authored in AS1.0 and 2.0 DisplayObjectContainer – has many useful subclasses such as Loader, Sprite and MovieClip InteractiveObject – it is the base class for all objects used to interact with the mouse and keyboard. MorphShape – These are created when you create a shape tween using Flash Authoring. They cannot be instantiated using ActionScript. Stage - It is created as a singleton instance for every application and is included at the top of the display list hierarchy.
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  Merely instantiating adisplay object does not add the display object to the display list. In order to add a display object we use the addChild() method. For example, to add an instance of TextField to the display list we use the following syntax this.addChild(textFieldObject);   Adding any visual element to the stage makes the element a child of the Stage Object. In order to manipulate the appearance of the Display object we use the methods and properties available in the Display Object class.
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  The Following Exampleshows the use of Events with Display object. You can find the example here and the source code here .
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  Flex 3 LiveDocsActionScript 3.0 Language Reference
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