Choice class in java

The Choice class presents a pop-up menu of choices. The current choice is displayed as the title of the menu. The following code example produces a pop-up menu:

Choice ColorChooser = new Choice(); ColorChooser.add("Green"); ColorChooser.add("Red"); ColorChooser.add("Blue");

After this choice menu has been added to a panel, it appears as follows in its normal state: In the picture, «Green» is the current choice. Pushing the mouse button down on the object causes a menu to appear with the current choice highlighted. Some native platforms do not support arbitrary resizing of Choice components and the behavior of setSize()/getSize() is bound by such limitations. Native GUI Choice components’ size are often bound by such attributes as font size and length of items contained within the Choice .

Nested Class Summary

Nested classes/interfaces inherited from class java.awt.Component

Field Summary

Fields inherited from class java.awt.Component

Fields inherited from interface java.awt.image.ImageObserver

Constructor Summary

Method Summary

Processes item events occurring on this Choice menu by dispatching them to any registered ItemListener objects.

Sets the selected item in this Choice menu to be the item whose name is equal to the specified string.

Methods inherited from class java.awt.Component

Methods inherited from class java.lang.Object

Constructor Detail

Choice

Creates a new choice menu. The menu initially has no items in it. By default, the first item added to the choice menu becomes the selected item, until a different selection is made by the user by calling one of the select methods.

Method Detail

addNotify

Creates the Choice ‘s peer. This peer allows us to change the look of the Choice without changing its functionality.

getItemCount

countItems

getItem

add

addItem

Obsolete as of Java 2 platform v1.1. Please use the add method instead. Adds an item to this Choice menu.

insert

Inserts the item into this choice at the specified position. Existing items at an index greater than or equal to index are shifted up by one to accommodate the new item. If index is greater than or equal to the number of items in this choice, item is added to the end of this choice. If the item is the first one being added to the choice, then the item becomes selected. Otherwise, if the selected item was one of the items shifted, the first item in the choice becomes the selected item. If the selected item was no among those shifted, it remains the selected item.

remove

Removes the first occurrence of item from the Choice menu. If the item being removed is the currently selected item, then the first item in the choice becomes the selected item. Otherwise, the currently selected item remains selected (and the selected index is updated accordingly).

remove

public void remove(int position)

Removes an item from the choice menu at the specified position. If the item being removed is the currently selected item, then the first item in the choice becomes the selected item. Otherwise, the currently selected item remains selected (and the selected index is updated accordingly).

removeAll

getSelectedItem

getSelectedObjects

Returns an array (length 1) containing the currently selected item. If this choice has no items, returns null .

getSelectedIndex

public int getSelectedIndex()

select

public void select(int pos)

Sets the selected item in this Choice menu to be the item at the specified position. Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent . The only way to trigger an ItemEvent is by user interaction.

select

Sets the selected item in this Choice menu to be the item whose name is equal to the specified string. If more than one item matches (is equal to) the specified string, the one with the smallest index is selected. Note that this method should be primarily used to initially select an item in this component. Programmatically calling this method will not trigger an ItemEvent . The only way to trigger an ItemEvent is by user interaction.

addItemListener

Adds the specified item listener to receive item events from this Choice menu. Item events are sent in response to user input, but not in response to calls to select . If l is null , no exception is thrown and no action is performed. Refer to AWT Threading Issues for details on AWT’s threading model.

removeItemListener

Removes the specified item listener so that it no longer receives item events from this Choice menu. If l is null , no exception is thrown and no action is performed. Refer to AWT Threading Issues for details on AWT’s threading model.

getItemListeners

getListeners

public EventListener> T[] getListeners(Class listenerType)

Returns an array of all the objects currently registered as FooListener s upon this Choice . FooListener s are registered using the addFooListener method. You can specify the listenerType argument with a class literal, such as FooListener.class . For example, you can query a Choice c for its item listeners with the following code:

ItemListener[] ils = (ItemListener[])(c.getListeners(ItemListener.class));

processEvent

Processes events on this choice. If the event is an instance of ItemEvent , it invokes the processItemEvent method. Otherwise, it calls its superclass’s processEvent method. Note that if the event parameter is null the behavior is unspecified and may result in an exception.

processItemEvent

An ItemListener object is registered via addItemListener .
Item events are enabled via enableEvents .

paramString

Returns a string representing the state of this Choice menu. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be null .

getAccessibleContext

Gets the AccessibleContext associated with this Choice . For Choice components, the AccessibleContext takes the form of an AccessibleAWTChoice . A new AccessibleAWTChoice instance is created if necessary.

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For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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