基本思想是您需要知道上次选择的字段。问题是,当您选择滑块时,它会触发一个焦点获得事件......
最简单的想法是使用FocusListener
仅注册到文本字段并保持对最后一个选定字段的引用。
当滑块更改时,您只需与最后选择的字段进行交互(如果不是null
)
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.FocusAdapter;
import java.awt.event.FocusEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
public class SliderControl {
public static void main(String[] args) {
new SliderControl();
}
public SliderControl() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JSlider slider;
private JTextField[] fields;
private JTextField selectedField;
public TestPane() {
setLayout(new GridBagLayout());
fields = new JTextField[3];
FocusHandler focusHandler = new FocusHandler();
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
for (int index = 0; index < 3; index++) {
fields[index] = new JTextField(3);
fields[index].addFocusListener(focusHandler);
add(fields[index], gbc);
gbc.gridy++;
}
gbc.fill = GridBagConstraints.HORIZONTAL;
slider = new JSlider();
slider.addChangeListener(new ChangeListener() {
@Override
public void stateChanged(ChangeEvent e) {
if (selectedField != null) {
selectedField.setText(String.valueOf(slider.getValue()));
}
}
});
add(slider, gbc);
}
protected class FocusHandler extends FocusAdapter {
@Override
public void focusGained(FocusEvent e) {
if (e.getComponent() instanceof JTextField) {
selectedField = (JTextField) e.getComponent();
}
}
}
}
}