问题
I'm trying to get the value returned by custom buttons passed to JOptionPane. However the buttons I pass don't return a value at all. Only when the exit button is pressed is a value of -1 returned. I need this because I am changing the properties of the buttons enabled or disabled. I assume I need the buttons to return some information to the JOptionPane in some way. Any idea?
JButton button1= new JButton("Button 1");
JButton button2= new JButton("Button 2");
button1.setEnabled(false);
int value = JOptionPane.showOptionDialog(null, "Heres a test message", "Test", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[]{button1, button2}, button1);
JOptionPane.showMessageDialog(null, "You entered " + value);
Nb This is related to my previous question - JOptionPane Grey Out One Button
I tried setting the value of the buttons like you said but they never return OK or CANCEL.
Whenever checking the value of the buttons, they never return the value I set them too.
JButton button1= new JButton("Button1");
JButton button2= new JButton("Button2");
button1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane pane = getOptionPane((JComponent)e.getSource());
// set the value of the option pane
pane.setValue(JOptionPane.OK_OPTION);
}
});
button2.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane pane = getOptionPane((JComponent)e.getSource());
// set the value of the option pane
pane.setValue(JOptionPane.CANCEL_OPTION);
}
});
if (JOptionPane.showOptionDialog(null, "Pick a button", "Pick", JOptionPane.OK_CANCEL_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[]{button1, button2}, button1) == JOptionPane.OK_OPTION) {
JOptionPane.showMessageDialog(null, "Button1");
}
else{
JOptionPane.showMessageDialog(null, "Button2");
}
See above, always I get the button2 popup no matter what.
回答1:
In the example I linked to you previous question, the buttons use the JOptionPane#setValue method to set the return value. This allows you to continue using the API as normal, while providing you with the customisation your after.
final JButton okay = new JButton("Ok");
okay.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane pane = getOptionPane((JComponent)e.getSource());
// set the value of the option pane
pane.setValue(JOptionPane.OK_OPTION);
}
});
Take a closer look at Disable ok button on JOptionPane.dialog until user gives an input
Updated
I've gone back through the code and correct the actionPerformed methods to enable it to return a valid value...
final JButton okay = new JButton("Ok");
okay.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane pane = getOptionPane((JComponent)e.getSource());
pane.setValue(okay);
}
});
okay.setEnabled(false);
final JButton cancel = new JButton("Cancel");
cancel.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane pane = getOptionPane((JComponent)e.getSource());
pane.setValue(cancel);
}
});
The value returned by the index of the value in the options array (last parameter)
So, for example...
int value = JOptionPane.showOptionDialog(
null,
field,
"Get",
JOptionPane.YES_NO_OPTION,
JOptionPane.QUESTION_MESSAGE,
null,
new Object[]{okay, cancel},
okay);
If the user clicks the okay button, the return value will be 0, or if they select the cancel button, it will be 1
回答2:
If you need this complex behavior, consider creating your own JDialog and then displaying it in a modal fashion.
If you have to use a JOptionPane, you can do this by extracting its JDialog and recursively iterating through its components til you find the one you want to disable and disable it:
import java.awt.Component;
import java.awt.Container;
import javax.swing.*;
public class Foo2 {
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
doRun();
}
});
}
public static void doRun() {
String[] options = {"Button 1", "Button 2", "Button 3"};
JOptionPane myOptionPane = new JOptionPane("Heres a test message",
JOptionPane.QUESTION_MESSAGE, JOptionPane.YES_NO_OPTION,
null, options, options[2]);
JDialog myDialog = myOptionPane.createDialog(null, "My Test");
myDialog.setModal(true);
inactivateOption(myDialog, options[1]);
myDialog.setVisible(true);
Object result = myOptionPane.getValue();
// Note: result might be null if the option is cancelled
System.out.println("result: " + result);
System.exit(0); // to stop Swing event thread
}
private static void inactivateOption(Container container, String text) {
Component[] comps = container.getComponents();
for (Component comp : comps) {
if (comp instanceof AbstractButton) {
AbstractButton btn = (AbstractButton) comp;
if (btn.getActionCommand().equals(text)) {
btn.setEnabled(false);
return;
}
} else if (comp instanceof Container) {
inactivateOption((Container) comp, text);
}
}
}
}
However for myself, I'd just create a JDialog.
回答3:
You don't have to define your buttons explicitly.
int result = JOptionPane.showOptionDialog(this, "Are you sure you want to...?", "Title", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, null, new String[] { "Yes", "No" }, JOptionPane.NO_OPTION);
if (result == JOptionPane.YES_OPTION) {
...
}
来源：https://stackoverflow.com/questions/14591089/joptionpane-passing-custom-buttons