CheckBox In Java
A check box is a graphical component that can
be in either an "on" (true) or "off" (false) state.
Clicking on a check box changes its state from "on" to
"off," or from "off" to "on."
Constructor :-
1.public Checkbox()
throws HeadlessException
Creates a check box with no label.
The state of this check box is set to
"off," and it is not part of any check box group.
2.
public Checkbox(String label)
Creates
a check box with the specified label.
The
state of this check box is set to "off,"
it is not part of any check box group.
Checkbox(String label,boolean state)
Creates a check box with the specified label
and sets the specified state. This check box is not part of any check box
group.
4.
Checkbox(String label, CheckboxGroup group,
boolean state)
Creates
a check box with the specified label, in the specified check box group, and set
to the specified state.
Checkbox constructors:
- Checkbox( )
- Checkbox(String str)
- Checkbox(String str, boolean on)
- Checkbox(String str, boolean on, CheckboxGroup cbGroup)
- Checkbox(String str, CheckboxGroup cbGroup, boolean on)
- These methods
- boolean getState( )
- void setState(boolean on)
- String getLabel( )
- void setLabel(String str)
- Handling Check Boxes
- Each time a check box is selected or deselected, an item event is generated
- Each listener implements the ItemListener interface
- Interface defines the itemStateChanged( ) method.
- getLabel
- public String getLabel() Gets the label of this check box. Returns the label of this check box, or null if this check box has no label.
- setLabel
- public void setLabel(String label)
- Sets this check box's label to be the string argument.
- getState
- public boolean getState()
- Determines whether this check box is in the "on" or "off" state.
- checkbox1.getState());
- g.drawString("Java: " + java.getState(),10,60);
- setState
- public void setState(boolean state Sets the state of this check box to the specified state.
- Enabling Checkbox checkbox1.setEnabled(false);
- Checking enable or not
- (checkbox1.isEnabled()
- Checkbox groups are collections of checkboxes with the special property that no more than one checkbox in the same group can be selected at a time. The checkboxes in a CheckboxGroup are often called radio buttons.
- CheckboxGroup cbg = new CheckboxGroup();
- To make check boxes act like radio buttons, use this constructor for each Checkbox in the group.
- public Checkbox(String label, CheckboxGroup cbg, boolean checked)The label is the label for this Checkbox. The CheckboxGroup is the group you want this Checkbox to belong to and must already exist.
