JSpinner: autoselect onFocus

问题

I want to implement autoselect when a user tabs through the JTextFields and JSpinners in my forms. For this I am using this Listener:

public class AutoSelect implements FocusListener {

    @Override
    public void focusGained(final FocusEvent e) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                if (e.getSource() instanceof JTextField) {
                    try {
                        JTextField t = (JTextField) e.getComponent();
                        t.selectAll();
                    } catch (ClassCastException ex) {
                        // 
                    }
                }else if (e.getSource() instanceof JSpinner){
                    JSpinner spinner = (JSpinner)e.getComponent();
                    JTextField tf = ((JSpinner.DefaultEditor)spinner.getEditor()).getTextField();  
                    tf.selectAll();
                }
            }
        });
    }

    @Override
    public void focusLost(FocusEvent e) {
        // 
    }
}

Only it doesn´t work for my spinners. The event is beeing fired, the correct lines are executed, only nothing happens. I suspect I am not using the .getTextField() correctly. Does anyone have a working solution for this ?

回答1:

tf.selectAll(); should be wrapped into invokeLater, everything with Focus is pretty asynchronous (more in Oracle tutorial How to use Focus, FocusSubsystem),
then invokeLater (not true in all cases for all JComponents, but by default) for JTextComponents move this event to the end of queue, works for me quite correctly

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

public class ComboBoxTwo extends JFrame {

    private static final long serialVersionUID = 1L;
    private JTextField text = new JTextField(15);
    private JSpinner spinner = new JSpinner(new SpinnerNumberModel(0, 0, 15, 1));

    public ComboBoxTwo() {
        text.setText("Something selectable");
        text.addFocusListener(fcsListener);
        JFormattedTextField format = ((JSpinner.DefaultEditor) spinner.getEditor()).getTextField();
        // or JTextField tf = ((JSpinner.DefaultEditor) spinner.getEditor()).getTextField();
        format.addFocusListener(fcsListener);
        //or tf.addFocusListener(fcsListener); // depends of type for SpinnerXxxModel 
        add(text, BorderLayout.NORTH);
        add(spinner, BorderLayout.SOUTH);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                JFrame frame = new ComboBoxTwo();
                frame.setDefaultCloseOperation(EXIT_ON_CLOSE);
                frame.pack();
                frame.setVisible(true);
            }
        });
    }
//
    private FocusListener fcsListener = new FocusListener() {
        @Override
        public void focusGained(FocusEvent e) {
            dumpInfo(e);
        }

        @Override
        public void focusLost(FocusEvent e) {
            dumpInfo(e);
        }

        private void dumpInfo(FocusEvent e) {
            System.out.println("Source  : " + name(e.getComponent()));
            System.out.println("Opposite : " + name(e.getOppositeComponent()));
            System.out.println("Temporary: " + e.isTemporary());
            final Component c = e.getComponent();//works for editable JComboBox too
            if (c instanceof JFormattedTextField) {
                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        ((JFormattedTextField) c).setText(((JFormattedTextField) c).getText());
                        ((JFormattedTextField) c).selectAll();
                    }
                });
            } else if (c instanceof JTextField) {
                SwingUtilities.invokeLater(new Runnable() {
                    @Override
                    public void run() {
                        ((JTextField) c).setText(((JTextField) c).getText());
                        ((JTextField) c).selectAll();
                    }
                });
            }
        }

        private String name(Component c) {
            return (c == null) ? null : c.getName();
        }
    };
}

来源：https://stackoverflow.com/questions/20971050/jspinner-autoselect-onfocus

标签

java

swing

focus

jspinner