Defines the contents of the label.

Constructor.

Create child objects of the component. This is an advanced method that you might override when creating a subclass of UIComponent.

A component that creates other components or objects within it is called a composite component. For example, the Flex ComboBox control is actually made up of a TextInput control to define the text area of the ComboBox, and a Button control to define the ComboBox arrow. Components implement the createChildren() method to create child objects (such as other components) within the component.

From within an override of the createChildren() method, you call the addChild() method to add each child object.

You do not call this method directly. Flex calls the createChildren() method in response to the call to the addChild() method to add the component to its parent.

Marks a component so that its measure() method gets called during a later screen update.

Invalidation is a useful mechanism for eliminating duplicate work by delaying processing of changes to a component until a later screen update. For example, if you want to change the text and font size, it would be wasteful to update the text immediately after you change it and then update the size when it gets set. It is more efficient to change both properties and then render the text with its new size once.

Invalidation methods rarely get called. In general, setting a property on a component automatically calls the appropriate invalidation method.

Calculates the default size, and optionally the default minimum size, of the component. This is an advanced method that you might override when creating a subclass of UIComponent.

You do not call this method directly. Flex calls the measure() method when the component is added to a container using the addChild() method, and when the component's invalidateSize() method is called.

When you set a specific height and width of a component, Flex does not call the measure() method, even if you explicitly call the invalidateSize() method. That is, Flex only calls the measure() method if the explicitWidth property or the explicitHeight property of the component is NaN.

In your override of this method, you must set the measuredWidth and measuredHeight properties to define the default size. You may optionally set the measuredMinWidth and measuredMinHeight properties to define the default minimum size.

Most components calculate these values based on the content they are displaying, and from the properties that affect content display. A few components simply have hard-coded default values.

The conceptual point of measure() is for the component to provide its own natural or intrinsic size as a default. Therefore, the measuredWidth and measuredHeight properties should be determined by factors such as:

• The amount of text the component needs to display.
• The styles, such as fontSize, for that text.
• The size of a JPEG image that the component displays.
• The measured or explicit sizes of the component's children.
• Any borders, margins, and gaps.

In some cases, there is no intrinsic way to determine default values. For example, a simple GreenCircle component might simply set measuredWidth = 100 and measuredHeight = 100 in its measure() method to provide a reasonable default size. In other cases, such as a TextArea, an appropriate computation (such as finding the right width and height that would just display all the text and have the aspect ratio of a Golden Rectangle) might be too time-consuming to be worthwhile.

The default implementation of measure() sets measuredWidth, measuredHeight, measuredMinWidth, and measuredMinHeight to 0.

Draws the object and/or sizes and positions its children. This is an advanced method that you might override when creating a subclass of UIComponent.

You do not call this method directly. Flex calls the updateDisplayList() method when the component is added to a container using the addChild() method, and when the component's invalidateDisplayList() method is called.

If the component has no children, this method is where you would do programmatic drawing using methods on the component's Graphics object such as graphics.drawRect().

If the component has children, this method is where you would call the move() and setActualSize() methods on its children.

Components may do programmatic drawing even if they have children. In doing either, you should use the component's unscaledWidth and unscaledHeight as its bounds.

It is important to use unscaledWidth and unscaledHeight instead of the width and height properties.

Parameters