Question

Java难题 是关于窗体创建的 下面的程序运行会出现两个窗体，怎么样才能合并成一个？？

import javax.swing.*;
import java.util.concurrent.*;
public class SubmitSwingProgram extends JFrame
{
JLabel label;
public static void run(final JFrame f, final int width, final int height)
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
f.setTitle(f.getClass().getSimpleName());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setSize(width, height);
f.setVisible(true);
}
});
}
public SubmitSwingProgram()
{
run(new JFrame(), 500, 300);
label = new JLabel("A Label");
add(label);
setVisible(true);
}
static SubmitSwingProgram ssp;
public static void main(String[] args) throws Exception
{
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
ssp = new SubmitSwingProgram();
}
});
TimeUnit.SECONDS.sleep(1);
SwingUtilities.invokeLater(new Runnable()
{
public void run()
{
ssp.label.setText("This is different");
}
});
}
}

Answer 1

SubmitSwingProgram 继承了JFrame，本身就是一个窗口
构造方法中
public SubmitSwingProgram()
{
run(new JFrame(), 500, 300);//这里又new了一个窗口
label = new JLabel("A Label");
add(label);
setVisible(true);//这里你让SubmitSwingProgram显示
}
当然会出现两个窗口

你到底要几个窗口？你的代码一团糟，多看看例子

Answer 2

晕 看代码中就都被回答完了……

以下修复后的代码

import javax.swing.*;

import java.awt.Dimension;
import java.util.concurrent.*;

public class SubmitSwingProgram extends JFrame {
JLabel label;

public static void runx(final JFrame f, final int width, final int height) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
f.setTitle(f.getClass().getSimpleName());
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setPreferredSize(new Dimension(height, width));
f.setVisible(true);
}
});
}
public SubmitSwingProgram() {
runx(this, 500, 300);
label = new JLabel("A Label");
add(label);
setVisible(true);
}

static SubmitSwingProgram ssp;

public static void main(String[] args) throws Exception {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
ssp = new SubmitSwingProgram();
}
});
TimeUnit.SECONDS.sleep(1);
SwingUtilities.invokeLater(new Runnable() {
public void run() {
ssp.label.setText("This is different");
}
});
}
}

Answer 3

构造函数
public SubmitSwingProgram()
{
run(new JFrame(), 500, 300);
label = new JLabel("A Label");
add(label);
setVisible(true);
}
里面第一行改为：
run(this, 500, 300);

Answer 4

写得真够乱