// Copyright 2007. Adobe Systems Incorporated. All Rights Reserved.
  package fl.accessibility {
          
          import fl.controls.LabelButton;
          import fl.controls.CheckBox;
          import fl.core.UIComponent;
  
      

The @ax-student-ar-fl-accessibility-CheckBoxAccImpl class, also called the CheckBox Accessibility Implementation class, is used to make a CheckBox component accessible. This class enables communication between a CheckBox component and a screen reader. Screen readers are used to translate screen content into synthesized speech or braille for visually impaired users. <p>The @ax-student-ar-fl-accessibility-CheckBoxAccImpl class supports system roles, object-based events, and states.</p> <p>A CheckBox reports the role <code>ROLE_SYSTEM_CHECKBUTTON</code> (0x2C) to a screen reader.</p> <p>A CheckBox reports the following states to a screen reader:</p> <ul> <li><code>STATE_SYSTEM_NORMAL</code> (0x00000000)</li> <li><code>STATE_SYSTEM_UNAVAILABLE</code> (0x00000001)</li> <li><code>STATE_SYSTEM_FOCUSED</code> (0x00000004)</li> <li><code>STATE_SYSTEM_PRESSED</code> (0x00000008)</li> <li><code>STATE_SYSTEM_CHECKED</code> (0x00000010)</li> <li><code>STATE_SYSTEM_FOCUSABLE</code> (0x00100000)</li> </ul> <p>A CheckBox dispatches the following events to a screen reader:</p> <ul> <li><code>EVENT_OBJECT_STATECHANGE</code> (0x800A)</li> <li><code>EVENT_OBJECT_NAMECHANGE</code> (0x800C)</li> </ul> <p>Screen reader users can activate a Checkbox component with the spacebar or the Enter key.</p>
see: fl.controls.CheckBox CheckBox @langversion 3.0 @playerversion Flash 9.0.28.0

  
          public class @ax-student-ar-fl-accessibility-CheckBoxAccImpl extends LabelButtonAccImpl {
          

@private Static variable triggering the <code>hookAccessibility()</code> method. This is used for initializing @ax-student-ar-fl-accessibility-CheckBoxAccImpl class to hook its <code>createAccessibilityImplementation()</code> method to CheckBox class before it gets called from UIComponent. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  private static var accessibilityHooked:Boolean = hookAccessibility();
  
          

@private Static method for swapping the <code>createAccessibilityImplementation()</code> method of CheckBox with the @ax-student-ar-fl-accessibility-CheckBoxAccImpl class. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  private static function hookAccessibility():Boolean {
                          CheckBox.createAccessibilityImplementation = createAccessibilityImplementation;
                          return true;
                  }
  
                  //--------------------------------------------------------------------------
                  //  Class constants
                  //--------------------------------------------------------------------------
  
          

@private @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  private static const STATE_SYSTEM_CHECKED:uint = 0x00000010;
  
                  //--------------------------------------------------------------------------
                  //  Class methods
                  //--------------------------------------------------------------------------
  
          

@private Method for creating the Accessibility class. This method is called from UIComponent.
parameter: component The UIComponent instance that this AccImpl instance is making accessible. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  public static function createAccessibilityImplementation(component:UIComponent):void {
                          component.accessibilityImplementation = new @ax-student-ar-fl-accessibility-CheckBoxAccImpl(component);
                  }
          
                  

Enables accessibility for a CheckBox component. This method is required for the compiler to activate the accessibility classes for a component. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  public static function enableAccessibility():void {
                  }
          
                  //--------------------------------------------------------------------------
                  //  Constructor
                  //--------------------------------------------------------------------------
          
          

@private @internal Nivesh says: I don't think we should document the constructors for the accessibility classes. End-users just have to call the static enableAccessibility method. They don't really create an instance of the classes. Creates a @ax-student-ar-fl-accessibility-CheckBoxAccImpl instance for the specified CheckBox component.
parameter: component The CheckBox instance that this @ax-student-ar-fl-accessibility-CheckBoxAccImpl instance makes accessible. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  public function @ax-student-ar-fl-accessibility-CheckBoxAccImpl(component:UIComponent) {
                          super(component);
                          role = 0x2C;
                  }
          
                  //--------------------------------------------------------------------------
                  //  Overridden methods: AccessibilityImplementation
                  //--------------------------------------------------------------------------
          
                  

@private IAccessible method for returning the state of the CheckBox. States are predefined for all the components in MSAA. Values are assigned to each state. Depending upon whether the CheckBox is checked or unchecked, a value is returned.
parameter: childID The child id.
returns: State. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  override public function get_accState(childID:uint):uint {
                          var accState:uint = getState(childID);
                          if (LabelButton(master).selected) {
                                  accState |= STATE_SYSTEM_CHECKED;
                          }
                          return accState;
                  }
          
                  

@private IAccessible method for returning the default action of the CheckBox, which is Check or UnCheck depending on the state.
parameter: childID The child id.
returns: DefaultAction. @langversion 3.0 @playerversion Flash 9.0.28.0

  
                  override public function get_accDefaultAction(childID:uint):String {
                          return LabelButton(master).selected ? "UnCheck" : "Check";
                  }
          }
  }
  

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[] readme course(s) preface I 1 2 II 3 4 III 5 6 7 IV 8 9 10 V 11 12 afterthought(s) appendix reference(s) example(s) resource(s) _

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(C) Æliens 27/08/2009

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