java 创建时如何将焦点设置在 JOptionPane 内的特定 JTextfield 上？
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/6478394/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to set focus on specific JTextfield inside JOptionPane when created?
提问by Eng.Fouad
I want to set the focus on a specific JTextField which is passed to the JOptionPane as Object Message. Here is my code (I want the focus on txt2 but the focus always is on txt1):
我想将焦点设置在作为对象消息传递给 JOptionPane 的特定 JTextField 上。这是我的代码（我希望将重点放在 txt2 上，但重点始终放在 txt1 上）：
import java.awt.*;
import java.util.*;
import javax.swing.*;
public class TextArea extends JPanel
{
private JTextArea txt1 = new JTextArea();
private JTextArea txt2 = new JTextArea();
public TextArea()
{
setLayout(null);
setPreferredSize(new Dimension(200,100));
txt1.setBounds (20, 20, 220, 20);
txt2.setBounds (20, 45, 220, 20);
txt1.setText("Text Field #1");
txt2.setText("Text Field #2");
add(txt1);
add(txt2);
txt2.requestFocus();
}
private void display()
{
Object[] options = {this};
JOptionPane pane = new JOptionPane();
pane.showOptionDialog(null, null, "Title", JOptionPane.DEFAULT_OPTION, JOptionPane.PLAIN_MESSAGE, null, options, txt2);
}
public static void main(String[] args)
{
new TextArea().display();
}
}
回答by aioobe
You could let the txt2component request focus once it is added by overriding addNotify. Like this:
你可以让txt2组件请求焦点一旦被覆盖加入addNotify。像这样：
private JTextArea txt2 = new JTextArea() {
public void addNotify() {
super.addNotify();
requestFocus();
}
};
Here's a fully functional / tested version of your program:
这是您程序的功能齐全/经过测试的版本：
import java.awt.Dimension;
import javax.swing.*;
public class Test extends JPanel {
private JTextArea txt1 = new JTextArea();
private JTextArea txt2 = new JTextArea() {
public void addNotify() {
super.addNotify();
requestFocus();
}
};
public Test() {
setLayout(null);
setPreferredSize(new Dimension(200, 100));
txt1.setBounds(20, 20, 220, 20);
txt2.setBounds(20, 45, 220, 20);
txt1.setText("Text Field #1");
txt2.setText("Text Field #2");
add(txt1);
add(txt2);
}
private void display() {
Object[] options = { this };
JOptionPane pane = new JOptionPane();
pane.showOptionDialog(null, null, "Title", JOptionPane.DEFAULT_OPTION,
JOptionPane.PLAIN_MESSAGE, null, options, txt2);
}
public static void main(String[] args) {
new Test().display();
}
}
回答by camickr
I gave you the answer in your last question (http://stackoverflow.com/questions/6475320/how-to-set-the-orientation-of-jtextarea-from-right-to-left-inside-joptionpane). The concept is the same. Think about the solution given and understand how it works so you can apply it in different situations.
我在上一个问题中给了你答案（http://stackoverflow.com/questions/6475320/how-to-set-the-orientation-of-jtextarea-from-right-to-left-inside-joptionpane）。这个概念是一样的。考虑给出的解决方案并了解它的工作原理，以便您可以将其应用于不同的情况。
If you still don't understand the suggestion then see DialogFocusfor reusable code.
如果您仍然不理解该建议，请参阅DialogFocus以获取可重用代码。
回答by Hovercraft Full Of Eels
Why not use a JDialog or JFrame for this purpose?
为什么不为此目的使用 JDialog 或 JFrame？
public void display2() {
JDialog dialog = new JDialog(null, "Title", ModalityType.APPLICATION_MODAL);
dialog.getContentPane().add(this);
dialog.pack();
dialog.setLocationRelativeTo(null);
txt2.requestFocusInWindow();
dialog.setVisible(true);
}
回答by Genhis
You could use a workaround proposed in JDK-5018574 bug report.
您可以使用JDK-5018574 错误报告中提出的解决方法。
Instead of
代替
txt2.requestFocus();
use
利用
txt2.addHierarchyListener(e -> {
if(e.getComponent().isShowing() && (e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0)
SwingUtilities.invokeLater(e.getComponent()::requestFocusInWindow);
});
I modified the solution to use Java 8 features. For older versions of Java, see the original workaround.
我修改了解决方案以使用 Java 8 功能。对于旧版本的 Java，请参阅原始解决方法。
