如何更新子JPanel中的组件时如何在父JPanel中触发操作(Java Swing)
我正在尝试在Java Swing中构建一个MVC应用程序。我有一个包含四个JComboBox的JPanel,这个JPanel嵌入到父JPanel中。除了子JPanel之外,父JPanel还有其他控件。
I am trying to build an MVC application in Java Swing. I have a JPanel that contains four JComboBoxes and this JPanel is embedded into a parent JPanel. The parent JPanel has other controls in addition to the child JPanel.
每当我更改JComboBoxes的值时,子JPanel的模型都会正确更新(它基本上是一个日期选择器一个组合框,每个组合框用于年,月,日和一小时)。我无法弄清楚的是,无论何时更改其中一个JComboBox,我都可以触发父JPanel模型更新自身以匹配存储在子JPanel模型中的值。
The child JPanel's model gets correctly updated whenever I change the values of the JComboBoxes (it's basically a date picker with one combo box each for year, month, day of month, and hour of day). What I cannot figure out is how I can trigger the parent JPanel's model to update itself to match the value stored in the child JPanel's model whenever one of the JComboBoxes is changed.
下面是我所掌握的结构的简化SSCCE。谢谢。
Below is a stripped down SSCCE of the structure of what I have so far. Thank you.
import java.awt.event.*;
import javax.swing.*;
public class Example extends JFrame {
public Example() {
super();
OuterView theGUI = new OuterView();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
add(theGUI);
pack();
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Example();
}
});
}
}
class OuterView extends JPanel {
public OuterView() {
super();
InnerView innerPanel = new InnerView();
JButton button = new JButton("display OuterView's model");
button.addActionListener(new ButtonListener());
add(innerPanel);
add(button);
}
private class ButtonListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent ae) {
System.out.println("button was clicked");
}
}
}
class InnerView extends JPanel {
public InnerView() {
super();
String[] items = new String[] {"item 1", "item 2", "item 3"};
JComboBox comboBox = new JComboBox(items);
comboBox.addActionListener(new ComboBoxListener());
add(comboBox);
}
private class ComboBoxListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent ae) {
String text = ((JComboBox) ae.getSource()).getSelectedItem().toString();
System.out.println("store " + text + " in InnerView's model");
System.out.println("now how do I cause OuterView's model to be updated to get the info from InnerView's model?");
}
}
}
您可以使用PropertyChangeListener,实际上每个组件都内置了一个。例如:
You could use a PropertyChangeListener, and in fact one is built into every component. e.g.:
import java.awt.event.*;
import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import javax.swing.*;
@SuppressWarnings("serial")
public class Example extends JFrame {
public Example() {
super();
OuterView theGUI = new OuterView();
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setResizable(false);
add(theGUI);
pack();
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new Example();
}
});
}
}
class OuterView extends JPanel {
private String innerValue = "";
public OuterView() {
super();
InnerView innerPanel = new InnerView();
innerPanel.addPropertyChangeListener(new PropertyChangeListener() {
@Override
public void propertyChange(PropertyChangeEvent evt) {
if (evt.getPropertyName().equals(InnerView.COMBO_CHANGED)) {
innerValue = evt.getNewValue().toString();
System.out.println("new value from inside of OuterView: "
+ innerValue);
}
}
});
JButton button = new JButton("display OuterView's model");
button.addActionListener(new ButtonListener());
add(innerPanel);
add(button);
}
private class ButtonListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent ae) {
System.out.println("button was clicked. innerValue: " + innerValue);
}
}
}
class InnerView extends JPanel {
public static final String COMBO_CHANGED = "Combo Changed";
// private SwingPropertyChangeSupport pcSupport = new
// SwingPropertyChangeSupport(this);
String oldValue = "";
public InnerView() {
super();
String[] items = new String[] { "item 1", "item 2", "item 3" };
JComboBox comboBox = new JComboBox(items);
comboBox.addActionListener(new ComboBoxListener());
add(comboBox);
}
private class ComboBoxListener implements ActionListener {
@Override
public void actionPerformed(ActionEvent ae) {
String text = ((JComboBox) ae.getSource()).getSelectedItem()
.toString();
firePropertyChange(COMBO_CHANGED, oldValue, text);
oldValue = text;
System.out.println("store " + text + " in InnerView's model");
}
}
}