摘自http://blog.csdn.net/zcsearching/article/details/50808446
使用BorderLayout时，中间的面板会随着窗体的变化而变化，其他区域的大小根据添加组件多少而变化。举个例子，现在想将一个面板固定到上边，高度为固定值，这是我们需要设置面板的高度。但是调用面板的 setSize()方法根本没有效果。调用 setMaximumSize()和setMinimumSize()都没有用。
最后才发现应该调用的是 setPreferredSize()才能达到效果。
请看栗子。
package com.wst.bj; import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit; import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField; public class LayoutDemo { public static void main(String[] args) {
new myFrame();
}
} /**
* @author liuyan
*
*/
class myFrame { JFrame jframe = new JFrame("搜索");
JTextField textField = new JTextField(20);
JButton jButton = new JButton("转到");
JButton jButton2 = new JButton("转到2");
JButton jButton3 = new JButton("转到3");
JButton jButton4 = new JButton("转到4");
JTextArea textArea = new JTextArea();
JPanel jPanel = new JPanel(new BorderLayout(5,20));
JPanel jPanel2 = new JPanel(new BorderLayout());
JPanel jPanel3 = new JPanel(new BorderLayout());
JPanel jPanel4 = new JPanel(new BorderLayout()); /**
*
*/
public myFrame() { init();
} /**
*
*/
private void init()
{
jframe.setLayout(new BorderLayout());
jframe.add(jPanel2, BorderLayout.SOUTH);
jframe.add(jPanel3, BorderLayout.EAST);
jframe.add(jPanel4, BorderLayout.WEST);
jframe.add(jPanel, BorderLayout.NORTH); jPanel.add(jButton, BorderLayout.EAST);
jPanel.add(textField, BorderLayout.CENTER); jPanel2.add(jButton2);
jPanel3.add(jButton3);
jPanel4.add(jButton4); jPanel.setPreferredSize(new Dimension(0, 150));
jPanel2.setPreferredSize(new Dimension(0, 150));
jPanel3.setPreferredSize(new Dimension(150, 0));
jPanel4.setPreferredSize(new Dimension(150, 0)); jframe.add(textArea, BorderLayout.CENTER); jframe.setVisible(true);
FrameUtil.initFram(jframe, 500, 700);
}
} class FrameUtil
{
public static void initFram(JFrame f, int width, int height)
{
Toolkit toolkit = Toolkit.getDefaultToolkit();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Dimension d = toolkit.getScreenSize();
int x = (int)d.getWidth();
int y = (int)d.getHeight();
f.setBounds((x-width)/2, (y - height )/2, width, height);
}
}
package com.wst.bj; import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.Toolkit; import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.JTextField; public class LayoutDemo { public static void main(String[] args) {
new myFrame();
}
} /**
* @author liuyan
*
*/
class myFrame { JFrame jframe = new JFrame("搜索");
JTextField textField = new JTextField(20);
JButton jButton = new JButton("转到");
JButton jButton2 = new JButton("转到2");
JButton jButton3 = new JButton("转到3");
JButton jButton4 = new JButton("转到4");
JTextArea textArea = new JTextArea();
JPanel jPanel = new JPanel(new BorderLayout(5,20));
JPanel jPanel2 = new JPanel(new BorderLayout());
JPanel jPanel3 = new JPanel(new BorderLayout());
JPanel jPanel4 = new JPanel(new BorderLayout()); /**
*
*/
public myFrame() { init();
} /**
*
*/
private void init()
{
jframe.setLayout(new BorderLayout());
jframe.add(jPanel2, BorderLayout.SOUTH);
jframe.add(jPanel3, BorderLayout.EAST);
jframe.add(jPanel4, BorderLayout.WEST);
jframe.add(jPanel, BorderLayout.NORTH); jPanel.add(jButton, BorderLayout.EAST);
jPanel.add(textField, BorderLayout.CENTER); jPanel2.add(jButton2);
jPanel3.add(jButton3);
jPanel4.add(jButton4); // jPanel.setPreferredSize(new Dimension(0, 150));
// jPanel2.setPreferredSize(new Dimension(0, 150));
// jPanel3.setPreferredSize(new Dimension(150, 0));
// jPanel4.setPreferredSize(new Dimension(150, 0)); jframe.add(textArea, BorderLayout.CENTER); jframe.setVisible(true);
FrameUtil.initFram(jframe, 500, 700);
}
} class FrameUtil
{
public static void initFram(JFrame f, int width, int height)
{
Toolkit toolkit = Toolkit.getDefaultToolkit();
f.setVisible(true);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
Dimension d = toolkit.getScreenSize();
int x = (int)d.getWidth();
int y = (int)d.getHeight();
f.setBounds((x-width)/2, (y - height )/2, width, height);
}
}