The API does not offer that directly but one simple way to do it is to scan the component hierarchy, looking for a JTextField
and then change the selection of that textfield.
Here is an example of that solution:
import java.awt.Component;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;
public class TestJFileChooser {
public TestJFileChooser() {
}
protected void initUI() {
JFrame frame = new JFrame(TestJFileChooser.class.getSimpleName());
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
final JButton button = new JButton("Click me");
button.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JFileChooser chooser = new JFileChooser();
chooser.setSelectedFile(new File(chooser.getCurrentDirectory(), "save.dat"));
final JTextField textField = getTexField(chooser);
if (textField != null) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
String text = textField.getText();
if (text != null) {
int index = text.lastIndexOf('.');
if (index > -1) {
textField.setSelectionStart(0);
textField.setSelectionEnd(index);
}
}
}
});
}
chooser.showSaveDialog(button);
}
private JTextField getTexField(Container container) {
for (int i = 0; i < container.getComponentCount(); i++) {
Component child = container.getComponent(i);
if (child instanceof JTextField) {
return (JTextField) child;
} else if (child instanceof Container) {
JTextField field = getTexField((Container) child);
if (field != null) {
return field;
}
}
}
return null;
}
});
frame.add(button);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
TestJFileChooser fc = new TestJFileChooser();
fc.initUI();
}
});
}
}