我用两个按钮制作了一个小程序。我标记
按钮中的一个退出程序,第二个按钮导入文件。
当有人按下程序时,我实际上让他们俩都退出了程序
问题是按钮占据了所有窗口,为什么呢?
我尝试了GridBagConstraints
来调整按钮的大小,但是没有运气,这是没有输入的完整类。
public class Window2 extends JFrame{
private static final long serialVersionUID = 1L;
public Window2(){
super ("ALANAZ imagtor");
setSize(600,400);
setDefaultCloseOperation(EXIT_ON_CLOSE);
JPanel pnl1 = new JPanel(new GridLayout());
JPanel pnl2 = new JPanel();
//button
JButton butn1 = new JButton("EXIT");
JButton butn2 =new JButton("IMPORT");
butn1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
JOptionPane.showMessageDialog(null, "exiting ... bye...");
System.exit(0);
}
});
butn2.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent ae){
JOptionPane.showMessageDialog(null, "can't import now exiting");
System.exit(0);
}
});
GridBagConstraints gb1 = new GridBagConstraints();
gb1.insets = new Insets(15,15,15,15);
//Jlabel
JLabel lbl1 = new JLabel("exit or import an image");
pnl1.add(butn1);
pnl1.add(butn2);
pnl2.add(lbl1);
add(pnl2, BorderLayout.SOUTH);
add(pnl1, BorderLayout.CENTER);
}}
最佳答案
您正在滥用布局管理器。您的pnl1 JPanel使用GridLayout(没有任何行或列常量吗?!),如果仅向其中添加一个组件,它将占用整个JPanel。您的代码中似乎包含GridBagConstraints,但是没有GridBagLayout,这使我感到困惑。
解决方案是继续阅读并了解如何使用布局管理器。请查看教程链接:Laying Out Components Within a Container。
关键是要记住,您可以在JPanels中嵌套JPanels。例如:
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.GridLayout;
import java.awt.event.*;
import javax.swing.*;
public class Window2 extends JFrame {
private static final long serialVersionUID = 1L;
private static final int PREF_W = 600;
private static final int PREF_H = 400;
public Window2() {
super("ALANAZ imagtor");
setDefaultCloseOperation(EXIT_ON_CLOSE);
int gap = 3;
JPanel buttonPanel = new JPanel(new GridLayout(1, 0, gap, 0));
buttonPanel.setBorder(BorderFactory.createEmptyBorder(gap, gap, gap, gap));
JPanel pnl2 = new JPanel();
JButton butn1 = new JButton("EXIT");
JButton butn2 = new JButton("IMPORT");
butn1.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
JOptionPane.showMessageDialog(null, "exiting ... bye...");
System.exit(0);
}
});
butn2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
JOptionPane.showMessageDialog(null, "can't import now exiting");
System.exit(0);
}
});
JLabel lbl1 = new JLabel("exit or import an image");
buttonPanel.add(butn1);
buttonPanel.add(butn2);
JPanel centerPanel = new JPanel(new BorderLayout());
centerPanel.add(buttonPanel, BorderLayout.SOUTH);
pnl2.add(lbl1);
add(pnl2, BorderLayout.SOUTH);
add(centerPanel, BorderLayout.CENTER);
}
@Override
public Dimension getPreferredSize() {
return new Dimension(PREF_W, PREF_H);
}
public static void main(String[] args) {
Window2 win2 = new Window2();
win2.pack();
win2.setLocationRelativeTo(null);
win2.setVisible(true);
}
}