如何在分派任何更多事件之前等待JOptionPane关闭 [英] How to wait for JOptionPane to be closed before dispatching any more events
问题描述
我有两个文本字段，我正在其间切换。在 focusLost（）我打开 JOptionPane 。我想在 JOptionPane 关闭后执行 focusGained（）中的代码。即使对话框是模态的，在 JOptionPane 关闭之前，也会调用 focusGained（）。有没有办法解决？
I have a couple text fields that I'm tabbing between. On focusLost() I am opening a JOptionPane. I would like the code in focusGained() to be executed AFTER the JOptionPane has been closed. Even though the dialog is modal, focusGained() is being called before the JOptionPane is closed. Is there any way around this?
发现这个类似的问题，但它似乎也没有解决。
在失去焦点后推迟事件排队
Found this similar question, but it doesn't seem to have been solved either. Postpone Event Queue after Focus Lost
这是一个代码示例。您会注意到在关闭JOptionPane之前会打印Focus Gained。
Here's a code sample. You'll notice "Focus Gained" is printed before the JOptionPane is closed.
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import javax.swing.BoxLayout;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class ShortTest implements FocusListener
{
private void go()
{
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
JTextField text1 = new JTextField();
text1.setName("text1");
text1.addFocusListener(this);
JTextField text2 = new JTextField();
text2.setName("text2");
text2.addFocusListener(this);
panel.add(new JLabel("tex1"));
panel.add(text1);
panel.add(new JLabel("text2"));
panel.add(text2);
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String [] args)
{
ShortTest test = new ShortTest();
test.go();
}
@Override
public void focusGained(FocusEvent e)
{
if (!e.isTemporary() && (e.getSource() instanceof JTextField))
{
System.out.println("Focus Gained: " + ((JTextField)e.getSource()).getName());
}
}
@Override
public void focusLost(FocusEvent e)
{
if (!e.isTemporary() && (e.getSource() instanceof JTextField))
{
JOptionPane.showOptionDialog(null, ((JTextField)e.getSource()).getName() + " lost focus", "Title", JOptionPane.DEFAULT_OPTION, 0, null, null, null);
}
}
}
推荐答案
也许你想要的不是一个焦点监听器（一个非常低级的构造），而是一个输入验证器（一个更高级别的构造）。这应该在焦点转移之前作出反应。例如，在下面的代码中，如果用户尝试在文本字段中输入非数字数据，则验证程序会做出反应。是的，这也可以使用DocumentFilter完成。
Perhaps what you want is not a focus listener (a very low-level construct) but rather an input verifier (a higher level construct). This should respond before the focus has shifted. For example, in the code below the verifier reacts if the user tries to enter non-numeric data into the text field. Yes this can also be done using a DocumentFilter.
import javax.swing.*;
public class VerifierEg extends JPanel {
private static final int FIELD_COUNT = 3;
public VerifierEg() {
InputVerifier inputVerifier = new InputVerifier() {
@Override
public boolean verify(JComponent input) {
final JTextField textField = (JTextField) input;
String text = textField.getText();
for (char c : text.toCharArray()) {
if (!Character.isDigit(c)) {
textField.setText("");
JOptionPane.showMessageDialog(VerifierEg.this, "Text: \""
+ text + "\" must hold only digits", "Text Field Error",
JOptionPane.ERROR_MESSAGE);
return false;
}
}
return true;
}
};
for (int i = 0; i < FIELD_COUNT; i++) {
JTextField field = new JTextField(6);
field.setInputVerifier(inputVerifier);
add(field);
}
}
private static void createAndShowGui() {
JFrame frame = new JFrame("Enter Numbers");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.getContentPane().add(new VerifierEg());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
createAndShowGui();
}
});
}
}
编辑：
InputVerifier即使您没有以任何特定方式验证输入，也可以为您的目的而工作。例如，修改代码：
The InputVerifier could work for your purpose, even if you're not verifying the input in any specific way. For example, to modify your code:
import java.awt.event.FocusEvent;
import java.awt.event.FocusListener;
import javax.swing.BoxLayout;
import javax.swing.InputVerifier;
import javax.swing.JComponent;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class ShortTest2 {
private void go() {
final JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JPanel panel = new JPanel();
panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));
InputVerifier inputVerifier = new InputVerifier() {
@Override
public boolean verify(JComponent input) {
JOptionPane.showMessageDialog(frame,
"Focus Lost on " + input.getName());
return true;
}
};
FocusListener focusListener = new FocusListener() {
@Override
public void focusLost(FocusEvent e) {
String name = ((JComponent)e.getSource()).getName();
System.out.println("Focus Lost: " + name );
}
@Override
public void focusGained(FocusEvent e) {
String name = ((JComponent)e.getSource()).getName();
System.out.println("Focus Gained: " + name );
}
};
JTextField[] textFields = new JTextField[2];
for (int i = 0; i < textFields.length; i++) {
JTextField textField = new JTextField(10);
String name = "text " + (i + 1);
textField.setName(name);
textField.setInputVerifier(inputVerifier);
textField.addFocusListener(focusListener);
panel.add(new JLabel(name));
panel.add(textField);
}
frame.setContentPane(panel);
frame.pack();
frame.setVisible(true);
}
public static void main(String[] args) {
ShortTest2 test = new ShortTest2();
test.go();
}
}
顺便提一下你的SSCCE
1+！
1+ for your SSCCE by the way!
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