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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.gui.QAccessible
com.trolltech.qt.gui.QAccessibleInterface
public abstract class QAccessibleInterface
The QAccessibleInterface class defines an interface that exposes information about accessible objects.
Accessibility tools (also called AT Clients), such as screen readers or braille displays, require high-level information about accessible objects in an application. Accessible objects provide specialized input and output methods, making it possible for users to use accessibility tools with enabled applications (AT Servers).
Every element that the user needs to interact with or react to is an accessible object, and should provide this information. These are mainly visual objects, such as widgets and widget elements, but can also be content, such as sounds.
The AT client uses three basic concepts to acquire information about any accessible object in an application:
The QAccessibleInterface defines the API for these three concepts.
The functions childCount and indexOfChild return the number of children of an accessible object and the index a child object has in its parent. The childAt function returns the index of a child at a given position.
The relationTo function provides information about how two different objects relate to each other, and navigate allows traversing from one object to another object with a given relationship.
The central property of an accessible objects is what role it has. Different objects can have the same role, e.g. both the "Add line" element in a scroll bar and the OK button in a dialog have the same role, "button". The role implies what kind of interaction the user can perform with the user interface element.
An object's state property is a combination of different state flags and can describe both how the object's state differs from a "normal" state, e.g. it might be unavailable, and also how it behaves, e.g. it might be selectable.
The text property provides textual information about the object. An object usually has a name, but can provide extended information such as a description, help text, or information about any keyboard accelerators it provides. Some objects allow changing the text property through the setText function, but this information is in most cases read-only.
The rect property provides information about the geometry of an accessible object. This information is usually only available for visual objects.
To enable the user to interact with an accessible object the object must expose information about the actions that it can perform. userActionCount returns the number of actions supported by an accessible object, and actionText returns textual information about those actions. doAction invokes an action.
Objects that support selections can define actions to change the selection.
A QAccessibleInterface provides information about the accessible object, and can also provide information for the children of that object if those children don't provide a QAccessibleInterface implementation themselves. This is practical if the object has many similar children (e.g. items in a list view), or if the children are an integral part of the object itself, for example, the different sections in a scroll bar.
If an accessible object provides information about its children through one QAccessibleInterface, the children are referenced using indexes. The index is 1-based for the children, i.e. 0 refers to the object itself, 1 to the first child, 2 to the second child, and so on.
All functions in QAccessibleInterface that take a child index relate to the object itself if the index is 0, or to the child specified. If a child provides its own interface implementation (which can be retrieved through navigation) asking the parent for information about that child will usually not succeed.
Nested Class Summary | |
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static class |
QAccessibleInterface.Target
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Nested classes/interfaces inherited from class com.trolltech.qt.gui.QAccessible |
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QAccessible.Action, QAccessible.Event, QAccessible.Method, QAccessible.Relation, QAccessible.RelationFlag, QAccessible.Role, QAccessible.State, QAccessible.StateFlag, QAccessible.Text |
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Method Summary | |
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abstract java.lang.String |
actionText(int action,
QAccessible.Text t,
int child)
Returns the text property t of the action action supported by the object, or of the object's child if child is not 0. |
abstract int |
childAt(int x,
int y)
Returns the 1-based index of the child that contains the screen coordinates (x, y). |
abstract int |
childCount()
Returns the number of children that belong to this object. |
abstract boolean |
doAction(int action,
int child,
java.util.List<java.lang.Object> params)
Asks the object, or the object's child if child is not 0, to execute action using the parameters, params. |
static QAccessibleInterface |
fromNativePointer(QNativePointer nativePointer)
This function returns the QAccessibleInterface instance pointed to by nativePointer |
abstract int |
indexOfChild(QAccessibleInterface arg__1)
Returns the 1-based index of the object arg__1 in this object's children list, or -1 if arg__1 is not a child of this object. |
java.lang.Object |
invokeMethod(QAccessible.Method method,
int child,
java.util.List<java.lang.Object> params)
Invokes a method on child with the given parameters params and returns the result of the operation as QVariant. |
abstract boolean |
isValid()
Returns true if all the data necessary to use this interface implementation is valid (e.g. all pointers are non-null); otherwise returns false. |
abstract QAccessibleInterface.Target |
navigate(QAccessible.RelationFlag relation,
int index)
Equivalent to navigate(relation, index, ). |
abstract QObject |
object()
Returns a pointer to the QObject this interface implementation provides information for. |
abstract QRect |
rect(int child)
Returns the geometry of the object, or of the object's child if child is not 0. |
abstract QAccessible.Relation |
relationTo(int child,
QAccessibleInterface other,
int otherChild)
Returns the relationship between this object's child and the other object's otherChild. |
abstract QAccessible.Role |
role(int child)
Returns the role of the object, or of the object's child if child is not 0. |
abstract void |
setText(QAccessible.Text t,
int child,
java.lang.String text)
Sets the text property t of the object, or of the object's child if child is not 0, to text. |
abstract QAccessible.State |
state(int child)
Returns the current state of the object, or of the object's child if child is not 0. |
java.util.Set<QAccessible.Method> |
supportedMethods()
Returns a QSet of Methods that are supported by this accessible interface. |
abstract java.lang.String |
text(QAccessible.Text t,
int child)
Returns the value of the text property t of the object, or of the object's child if child is not 0. |
abstract int |
userActionCount(int child)
Returns the number of custom actions of the object, or of the object's child if child is not 0. |
Methods inherited from class com.trolltech.qt.gui.QAccessible |
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isActive, queryAccessibleInterface, setRootObject, updateAccessibility |
Methods inherited from class com.trolltech.qt.QtJambiObject |
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dispose, disposed, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class java.lang.Object |
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clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Method Detail |
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public final java.lang.Object invokeMethod(QAccessible.Method method, int child, java.util.List<java.lang.Object> params)
Invokes a method on child with the given parameters params and returns the result of the operation as QVariant.
Note that the type of the returned QVariant depends on the action.
Returns an invalid QVariant if the object doesn't support the action.
public final java.util.Set<QAccessible.Method> supportedMethods()
Returns a QSet of Methods that are supported by this accessible interface.
public abstract java.lang.String actionText(int action, QAccessible.Text t, int child)
Returns the text property t of the action action supported by the object, or of the object's child if child is not 0.
public abstract int childAt(int x, int y)
Returns the 1-based index of the child that contains the screen coordinates (x, y). This function returns 0 if the point is positioned on the object itself. If the tested point is outside the boundaries of the object this function returns -1.
This function is only relyable for visible objects (invisible object might not be laid out correctly).
All visual objects provide this information.
public abstract int childCount()
Returns the number of children that belong to this object. A child can provide accessibility information on its own (e.g. a child widget), or be a sub-element of this accessible object.
All objects provide this information.
public abstract boolean doAction(int action, int child, java.util.List<java.lang.Object> params)
Asks the object, or the object's child if child is not 0, to execute action using the parameters, params. Returns true if the action could be executed; otherwise returns false.
action can be a predefined or a custom action.
public abstract int indexOfChild(QAccessibleInterface arg__1)
Returns the 1-based index of the object arg__1 in this object's children list, or -1 if arg__1 is not a child of this object. 0 is not a possible return value.
All objects provide this information about their children.
public abstract boolean isValid()
Returns true if all the data necessary to use this interface implementation is valid (e.g. all pointers are non-null); otherwise returns false.
public abstract QAccessibleInterface.Target navigate(QAccessible.RelationFlag relation, int index)
Equivalent to navigate(relation, index, ).
public abstract QObject object()
Returns a pointer to the QObject this interface implementation provides information for.
public abstract QRect rect(int child)
Returns the geometry of the object, or of the object's child if child is not 0. The geometry is in screen coordinates.
This function is only reliable for visible objects (invisible objects might not be laid out correctly).
All visual objects provide this information.
public abstract QAccessible.Relation relationTo(int child, QAccessibleInterface other, int otherChild)
Returns the relationship between this object's child and the other object's otherChild. If child is 0 the object's own relation is returned.
The returned value indicates the relation of the called object to the other object, e.g. if this object is a child of other the return value will be Child.
The return value is a combination of the bit flags in the QAccessible::Relation enumeration.
All objects provide this information.
public abstract QAccessible.Role role(int child)
Returns the role of the object, or of the object's child if child is not 0. The role of an object is usually static.
All accessible objects have a role.
public abstract void setText(QAccessible.Text t, int child, java.lang.String text)
Sets the text property t of the object, or of the object's child if child is not 0, to text.
Note that the text properties of most objects are read-only.
public abstract QAccessible.State state(int child)
Returns the current state of the object, or of the object's child if child is not 0. The returned value is a combination of the flags in the QAccessible::StateFlag enumeration.
All accessible objects have a state.
public abstract java.lang.String text(QAccessible.Text t, int child)
Returns the value of the text property t of the object, or of the object's child if child is not 0.
The Name is a string used by clients to identify, find, or announce an accessible object for the user. All objects must have a name that is unique within their container. The name can be used differently by clients, so the name should both give a short description of the object and be unique.
An accessible object's Description provides textual information about an object's visual appearance. The description is primarily used to provide greater context for vision-impaired users, but is also used for context searching or other applications. Not all objects have a description. An "OK" button would not need a description, but a tool button that shows a picture of a smiley would.
The Value of an accessible object represents visual information contained by the object, e.g. the text in a line edit. Usually, the value can be modified by the user. Not all objects have a value, e.g. static text labels don't, and some objects have a state that already is the value, e.g. toggle buttons.
The Help text provides information about the function and usage of an accessible object. Not all objects provide this information.
The Accelerator is a keyboard shortcut that activates the object's default action. A keyboard shortcut is the underlined character in the text of a menu, menu item or widget, and is either the character itself, or a combination of this character and a modifier key like Alt, Ctrl or Shift. Command controls like tool buttons also have shortcut keys and usually display them in their tooltip.
All objects provide a string for Name.
public abstract int userActionCount(int child)
Returns the number of custom actions of the object, or of the object's child if child is not 0.
The Action type enumerates predefined actions: these are not included in the returned value.
public static QAccessibleInterface fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.
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