public abstract class InputVerifier extends Object
InputVerifier
and, using JComponent
's setInputVerifier
method, attach an instance of their subclass to the JComponent
which is the source of the focus transfer operation. The InputVerifier
also provides the possibility to validate against the target of the focus transfer which may reject the focus. Before focus is transferred from the source Swing component to the target Swing component, the input verifier's shouldYieldFocus(source, target)
method is called. Focus is transferred only if that method returns true
. The following example has two text fields, with the first one expecting the string "pass" to be entered by the user. If either that string is entered in the first text field or the second text field contains "accept" string, then the user can advance focus to the second text field by clicking in it or by pressing TAB. However, if another string is entered in the first text field and the second text field does not contain "accept", then the user will be unable to transfer focus to the second text field.
import java.awt.*; import javax.swing.*; // This program demonstrates the use of the Swing InputVerifier class. // It creates two text fields; the first of the text fields expects the // string "pass" as input, and will allow focus to advance to the second text // field if either that string is typed in by the user or the second // field contains "accept" string. public class VerifierTest extends JFrame { public VerifierTest() { JTextField field1 = new JTextField("Type \"pass\" here"); JTextField field2 = new JTextField("or \"accept\" here"); getContentPane().add(field1, BorderLayout.NORTH); getContentPane().add(field2, BorderLayout.SOUTH); field1.setInputVerifier(new InputVerifier() { public boolean verify(JComponent input) { return "pass".equals(((JTextField) input).getText()); } public boolean verifyTarget(JComponent input) { return "accept".equals(((JTextField) input).getText()); } public boolean shouldYieldFocus(JComponent source, JComponent target) { return verify(source) || verifyTarget(target); } }); pack(); setVisible(true); } public static void main(String[] args) { SwingUtilities.invokeLater(VerifierTest::new); } }
Modifier | Constructor | Description |
---|---|---|
protected |
Constructor for subclasses to call. |
Modifier and Type | Method | Description |
---|---|---|
boolean |
shouldYieldFocus |
Deprecated. |
boolean |
shouldYieldFocus |
Is called by Swing if this InputVerifier is assigned to the source Swing component to check whether the requested focus transfer from the source to target is allowed. |
abstract boolean |
verify |
Checks whether the JComponent's input is valid. |
boolean |
verifyTarget |
Checks whether the target JComponent that will be receiving the focus is ready to accept it. |
protected InputVerifier()
public abstract boolean verify(JComponent input)
input
- the JComponent to verifytrue
when valid, false
when invalid@Deprecated(since="9") public boolean shouldYieldFocus(JComponent input)
shouldYieldFocus(JComponent, JComponent)
instead.verify(input)
to ensure that the input is valid. This method can have side effects. In particular, this method is called when the user attempts to advance focus out of the argument component into another Swing component in this window. If this method returns true
, then the focus is transferred normally; if it returns false
, then the focus remains in the argument component.input
- the JComponent to verifytrue
when valid, false
when invalidpublic boolean verifyTarget(JComponent target)
true
.target
- the target JComponent to verifytrue
when valid, false
when invalidpublic boolean shouldYieldFocus(JComponent source, JComponent target)
InputVerifier
is assigned to the source
Swing component to check whether the requested focus transfer from the source
to target
is allowed. This method can have side effects. If this method returns true
, then the focus is transferred normally; if it returns false
, then the focus remains in the first argument component.verify(input)
and verifyTarget(input)
to ensure that both the source and the target components are in valid state.source
- the source JComponent of the focus transfertarget
- the target JComponent of the focus transfertrue
when valid, false
when invalid
© 1993, 2023, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.
https://docs.oracle.com/en/java/javase/21/docs/api/java.desktop/javax/swing/InputVerifier.html
shouldYieldFocus(JComponent, JComponent)
instead.