AccessibleContext (BlackBerry JDE 5.0.0 API Reference)

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net.rim.device.api.ui.accessibility
Interface AccessibleContext

public interface AccessibleContext

AccessibleContext represents the minimum information all accessible objects provide. This information includes the accessible name, role, and state of the object, as well as information about its parent and children. AccessibleContext also contains methods for obtaining more specific accessibility information about a component. If the component supports them, these methods will return an object that implements one or more of the following interfaces:

AccessibleText - the object presents editable textual information on the display. This interface provides the standard mechanism for an assistive technology to access that text via its content, attributes, and spatial location. Any object that contains editable text should support this interface.
AccessibleTable - the object presents tabular information on the display. This interface provides the standard mechanism for an assistive technology to access table columns and rows and current selection. Any object that represents a table should support this interface.
AccessibleValue - the object supports a numerical value. This interface provides the standard mechanism for an assistive technology to determine and set the current value of the object, as well as obtain its minimum and maximum values. Any object that supports a numerical value should support this interface.

Since:: BlackBerry API 4.6.1

Field Summary
`static int`	`ACCESSIBLE_CARET_CHANGED` Specifies caret movement event.
`static int`	`ACCESSIBLE_CHILD_CHANGED` Specifies child change event.
`static int`	`ACCESSIBLE_NAME_CHANGED` Specifies element name change.
`static int`	`ACCESSIBLE_SELECTION_CHANGED` Specifies selection change event.
`static int`	`ACCESSIBLE_STATE_CHANGED` Specifies accessible state transition event type.
`static int`	`ACCESSIBLE_TEXT_CHANGED` Specifies text change event.
`static int`	`ACCESSIBLE_VALUE_CHANGED` Specifies numerical or sequential value change.

Method Summary
`AccessibleContext`	`getAccessibleChildAt(int index)` Returns the specified Accessible child of the object.
`int`	`getAccessibleChildCount()` Return number of children for conatiners.
`String`	`getAccessibleName()` Returns accessible name of the element.
`AccessibleContext`	`getAccessibleParent()` Returns the parent context of this, typically the containing Manager or Screen.
`int`	`getAccessibleRole()` Returns accessible role of the element.
`AccessibleContext`	`getAccessibleSelectionAt(int index)` Returns the context of a selected item indicated by `index` out of the collection of selected items.
`int`	`getAccessibleSelectionCount()` Returns the number of items currently selected.
`int`	`getAccessibleStateSet()` Returns current set of states.
`AccessibleTable`	`getAccessibleTable()` Returns the AccessibleTable associated with an object.
`AccessibleText`	`getAccessibleText()` Returns accessible text for textual fields.
`AccessibleValue`	`getAccessibleValue()` Returns accessible value for numerical fields.
`boolean`	`isAccessibleChildSelected(int index)` Determines if the current child of this object is selected.
`boolean`	`isAccessibleStateSet(int state)` Determines whether or not `state` is set on this accessible element.

Field Detail

ACCESSIBLE_STATE_CHANGED

static final int ACCESSIBLE_STATE_CHANGED

Specifies accessible state transition event type. Can be fired by all accessible elements.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_TEXT_CHANGED

static final int ACCESSIBLE_TEXT_CHANGED

Specifies text change event. Usually fired by AccessibleText elements.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_CARET_CHANGED

static final int ACCESSIBLE_CARET_CHANGED

Specifies caret movement event. Usually fired by AccessibleText elements.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_CHILD_CHANGED

static final int ACCESSIBLE_CHILD_CHANGED

Specifies child change event. Fired by container UI elements, such as Screen, ListField, ComboFields, etc. when child is added or removed from the container.

The two notification parameters in the AccessibleEventListener.accessibleEventOccurred(int, Object, Object, AccessibleContext) method may optionally provide information about which container elements have been removed and added. This may help assistive technology to read only the affected elements if container has many of them. Both parameters are optional, however, if any of them is provided then the set must be complete meaning no other components were added or removed from the container. For example, if a screen changes dramatically affecting many fields then it is better to pass NULL parameter values indicating that screen reader should re-read the whole screen. On the other hand if relatively small number of fields were added or removed from the screen with big number of fields then it is advised to provide only the set of changed fields. In order to pass affected elements the two method parameter should be an array with the following type: AccessibleContext[]. The oldValue (2nd method parameter) contains container elements that existed before the notification and were removed. Similarly, the newValue (3rd method parameter) contains new elements that were added.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_SELECTION_CHANGED

static final int ACCESSIBLE_SELECTION_CHANGED

Specifies selection change event. Fired by container elements that have its children selected, such as ListField, TreeField, Tables. Also fired by a TextField when user changes text selection.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_VALUE_CHANGED

static final int ACCESSIBLE_VALUE_CHANGED

Specifies numerical or sequential value change. Fired by GaugeField that has range of values and DateField children such as Month field. This event may be fired by a component that doesn't support AccessibleContext.getAccessibleValue() method.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

ACCESSIBLE_NAME_CHANGED

static final int ACCESSIBLE_NAME_CHANGED

Specifies element name change. Fired by any accessible element when its name changes.

See Also:: Constant Field Values
Since:: BlackBerry API 4.6.1

Method Detail

getAccessibleChildAt

AccessibleContext getAccessibleChildAt(int index)

Returns the specified Accessible child of the object. The Accessible children of an Accessible object are zero-based, so the first child of an Accessible child is at index 0, the second child is at index 1, and so on.

Parameters:: index - Index of child requested.
Returns:: child at index if within limits, null otherwise.
Since:: BlackBerry API 4.6.1

getAccessibleChildCount

int getAccessibleChildCount()

Return number of children for conatiners.

Returns:: number of children if container, 0 otherwise.
Since:: BlackBerry API 4.6.1

getAccessibleName

String getAccessibleName()

Returns accessible name of the element.

Returns:: accessible name of field if available, null otherwise.
Since:: BlackBerry API 4.6.1

getAccessibleParent

AccessibleContext getAccessibleParent()

Returns the parent context of this, typically the containing Manager or Screen.

For Screens/Dialogs this returns null.

For Fields - this returns the Screen (e.g. Dialog) containing the Field.

For complex Field elements (e.g. menu items, etc) - this returns the Field (e.g. menu.

Returns:: accessible parent of the this component if available, null otherwise.
Since:: BlackBerry API 4.6.1

getAccessibleRole

int getAccessibleRole()

Returns accessible role of the element.

Returns:: accessible role of field
See Also:: AccessibleRole
Since:: BlackBerry API 4.6.1

getAccessibleSelectionAt

AccessibleContext getAccessibleSelectionAt(int index)

Returns the context of a selected item indicated by index out of the collection of selected items.

For cases where there is only 1 item selected at a time only the index of 0 is valid.

For classes that allow multi-selection the index is the position in the list of selected items where 0 indicates the start of the selection.

Parameters:: index - Index of selelected item, does not correspond to the child index.
Returns:: the i^th selected child.
Since:: BlackBerry API 4.6.1

getAccessibleSelectionCount

int getAccessibleSelectionCount()

Returns the number of items currently selected. If no children are selected, returns 0.

Returns:: number of selected children if any.
Since:: BlackBerry API 4.6.1

getAccessibleStateSet

int getAccessibleStateSet()

Returns current set of states. The value represents a mask with bit flags.

Returns:: set of accessible states currently set on this field.
See Also:: AccessibleState
Since:: BlackBerry API 4.6.1

getAccessibleTable

AccessibleTable getAccessibleTable()

Returns the AccessibleTable associated with an object.

Returns:: an AccessibleTable if supported by object, otherwise null.
Since:: BlackBerry API 4.6.1

getAccessibleText

AccessibleText getAccessibleText()

Returns accessible text for textual fields.

Returns:: accessible text of the field if available, otherwise null.
Since:: BlackBerry API 4.6.1

getAccessibleValue

AccessibleValue getAccessibleValue()

Returns accessible value for numerical fields.

This method should is supported by components that represent ranged set of numerical values, such as GaugeField. Those fields that have ranged non-numerical values won't utilize this method, such as DateField.

Returns:: accessible value if available, otherwise null.
Since:: BlackBerry API 4.6.1

isAccessibleChildSelected

boolean isAccessibleChildSelected(int index)

Determines if the current child of this object is selected.

Parameters:: index - Index of child.
Returns:: true if child is selected.
Since:: BlackBerry API 4.6.1

isAccessibleStateSet

boolean isAccessibleStateSet(int state)

Determines whether or not state is set on this accessible element.

The method parameter should be one of the states flags constants from the AccessibleState class. If the state method parameter contains more than one states flag then the returning value will be true if any of the given states is possessed by the component, false if component doesn't have any of the given states.

Parameters:: state - Determine if this state flag belongs to the set.
Returns:: true if the state is in the set.
Since:: BlackBerry API 4.6.1