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Re: How to detect focus l

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  To: comp.lang.java.gui

Ian Wilson wrote:
> clearlight@cantv.net wrote:
>> Hi,
>>
>> I am new to Java. As a basic learning project, I started writing a no-
>> frill small general ledger application.
>>
>> The basic design is a Frame containing a menu and a JTabbedPanel. When
>> a menu option is selected, a component derived from JPanel containing
>> the graphical interface for the data entry of the selected option is
>> created, added to the JTabbedPane component and the corresponding Tab
>> is selected.
>>
>> Inside any of this panels, there are JTextFields that have to be
>> validated (via InputVerifiers).
>>
>> Now, if focus is inside any of this JTextFields, and I select a new
>> option from the frame's menu, validation shouldn't be fired.
>>
>> So far, I have tried to add a FocusListener to the JPanel descendents,
>> but it doesn't work as I expected: JPanel fires a focusLost event when
>> focus enters a JTextField contained within the panel itself, and fires
>> nothing when a menu option is selected.
>>
>> If I establish a dependency between the main JFrame and the contained
>> JPanel derivates, I might perhaps design a sort of bidirectional
>> notification protocol, but I would like to avoid any dependence that
>> can be avoided.
>>
>> So, is there a standard event that lets me know when the focus leaves
>> a JPanel (FocusListener doesn't work, because -at least in my
>> configuration: NetBeans 5.5, JDK 1.6, WinXP- it fires when a control
>> within the panel gains focus)?
>>


>
> I had a similar problem, an input panel with OK and Cancel buttons. If the 
> user is editing a JTextField then clicks Cancel, you don't want the 
> validation to kick in. I used this approach:
>
>     cancelButton.setVerifyInputWhenFocusTarget(false);
>
> In your shoes I'd read the docs to see if 
> .setVerifyInputWhenFocusTarget(false) can be applied to your JMenuItems


Strange, that JMenu, JMenuBar don't seem to honor
.setVerifyInputWhenFocusTarget(false)

I could only get your suggestion to work using:
f.getRootPane().setVerifyInputWhenFocusTarget(false);
as below. I don't know what implications that may hold.
What about pop-up context menus?

Thanks,
Jeff Higgins

import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;

public class TestFocus {

  private static void createGUI() {
    JFrame f = new JFrame();
    JMenuBar menuBar = new JMenuBar();
    JMenu menu = new JMenu("Test");
    menu.setMnemonic(KeyEvent.VK_T);
    menuBar.add(menu);

    JTextField textFieldOne = new JTextField ();
    textFieldOne.setInputVerifier(new TestVerifier());
    JTextField textFieldTwo = new JTextField ("TextField2");
    JButton button = new JButton("Test");

    //menu.setVerifyInputWhenFocusTarget(false);
    f.getRootPane().setVerifyInputWhenFocusTarget(false);

    f.setJMenuBar(menuBar);
    f.getContentPane().add (textFieldOne, BorderLayout.NORTH);
    f.getContentPane().add (textFieldTwo, BorderLayout.CENTER);
    f.getContentPane().add (button, BorderLayout.SOUTH);
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    f.pack();
    f.setVisible(true);
  }

  static class TestVerifier extends InputVerifier {
    public boolean verify(JComponent input) {
      JTextField tf = (JTextField) input;
      System.out.println("verify");
      return "pass".equals(tf.getText());
    }
  }

  public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
      public void run() {
        createGUI();
      }
    });
  }
}

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Thread

How to detect focus lost "clearlight" <clearlight@THRWHITE.remove-dii-this> - 2011-04-27 15:33 +0000
  Re: How to detect focus l "Ian Wilson" <ian.wilson@THRWHITE.remove-dii-this> - 2011-04-27 15:33 +0000
    Re: How to detect focus l "Jeff Higgins" <jeff.higgins@THRWHITE.remove-dii-this> - 2011-04-27 15:33 +0000
      Re: How to detect focus l "Jeff Higgins" <jeff.higgins@THRWHITE.remove-dii-this> - 2011-04-27 15:33 +0000

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