Swing GridBagLayout 布局的问题
窗体需要分布三部分，左、中、右，而且随着窗体缩放的时候 ，中间部分保持不变，左、右同比例变化 ，于是使用了 GridBagLayout
GridBagLayout gbl_centerPanel = new GridBagLayout(); gbl_centerPanel.columnWidths = new int[] { 3, 1, 3 }; gbl_centerPanel.rowHeights = new int[] { 1 }; gbl_centerPanel.columnWeights = new double[] { 1.0, 0, 1.0 }; gbl_centerPanel.rowWeights = new double[] { 1.0 }; centerPanel.setLayout(gbl_centerPanel);double[][] size = { {0.5, TableLayout.PREFERRED, 0.5}, {TableLayout.FILL}};Container container = frame.getContentPane();container .setLayout(new TableLayout(size));container .add(new LeftPanel(), "0, 0");container .add(new CenterPanel(), "1, 0");container .add(new RightPanel(), "2, 0");
[解决办法]
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Calculator extends JFrame
{
private JTextField displayField;// 计算结果显示区
private String lastCommand;// 保存+,-,*,/,=命令
private double result;// 保存计算结果
private boolean start;// 判断是否为数字的开始
private Container container;
private GridBagLayout layout;
private GridBagConstraints constraints;
public Calculator()
{
super("java_刘阳");
container = getContentPane();
layout = new GridBagLayout();
container.setLayout(layout);
constraints = new GridBagConstraints();
start = true;
result = 0;
lastCommand = "=";
displayField = new JTextField(20);
displayField.setHorizontalAlignment(JTextField.RIGHT);
//注意这里
constraints.gridx =0;
constraints.gridy =0;
constraints.gridwidth = 3; //在第几格显示
constraints.gridheight = 1;
constraints.fill = GridBagConstraints.BOTH;
constraints.weightx = 100; //调整比例
constraints.weighty = 100;
layout.setConstraints(displayField, constraints);
container.add(displayField);
ActionListener insert = new InsertAction();
ActionListener command = new CommandAction();
addButton("Backspace", 0, 1, 2, 1, insert);
addButton("CE", 2, 1, 1, 1, insert);
addButton("C", 3, 1, 1, 1, insert);
addButton("7", 0, 2, 1, 1, insert);
addButton("8", 1, 2, 1, 1, insert);
addButton("9", 2, 2, 1, 1, insert);
addButton("/", 3, 2, 1, 1, command);
//
// addButton("4", 0, 3, 1, 1, insert);
//
// addButton("5", 1, 3, 1, 1, insert);
//
// addButton("6", 2, 3, 1, 1, insert);
// addButton("*", 3, 3, 1, 1, command);
//
// addButton("1", 0, 4, 1, 1, insert);
//
// addButton("2", 1, 4, 1, 1, insert);
//
// addButton("3", 2, 4, 1, 1, insert);
//
// addButton("-", 3, 4, 1, 1, command);
//
// addButton("0", 0, 5, 1, 1, insert);
//
// addButton("+/-", 1, 5, 1, 1, insert);// 只显示"-"号,"+"没有实用价值
//
// addButton(".", 2, 5, 1, 1, insert);
//
// addButton("+", 3, 5, 1, 1, command);
//
// addButton("=", 0, 6, 4, 1, command);
setSize(300, 300);
setVisible(true);
}
private void addButton(String label, int row, int column, int with,
int height, ActionListener listener)
{
JButton button = new JButton(label);
constraints.gridx = row;
constraints.gridy = column;
constraints.gridwidth = with;
constraints.gridheight = height;
constraints.fill = GridBagConstraints.BOTH;
button.addActionListener(listener);
layout.setConstraints(button, constraints);
container.add(button);
}
private class InsertAction implements ActionListener
{
public void actionPerformed(ActionEvent event)
{
String input = event.getActionCommand();
if (start)
{
displayField.setText("");
start = false;
if (input.equals("+/-"))
displayField.setText(displayField.getText() + "-");
}
if (!input.equals("+/-"))
{
if (input.equals("Backspace"))
{
String str = displayField.getText();
if (str.length() > 0)
displayField
.setText(str.substring(0, str.length() - 1));
}
else if (input.equals("CE") || input.equals("C"))
{
displayField.setText("0");
start = true;
}
else
displayField.setText(displayField.getText() + input);
}
}
}
private class CommandAction implements ActionListener
{
public void actionPerformed(ActionEvent evt)
{
String command = evt.getActionCommand();
if (start)
{
lastCommand = command;
}
else
{
calculate(Double.parseDouble(displayField.getText()));
lastCommand = command;
start = true;
}
}
}
public void calculate(double x)
{
if (lastCommand.equals("+"))
result += x;
else if (lastCommand.equals("-"))
result -= x;
else if (lastCommand.equals("*"))
result *= x;
else if (lastCommand.equals("/"))
result /= x;
else if (lastCommand.equals("="))
result = x;
displayField.setText("" + result);
}
public static void main(String[] args)
{
Calculator calculator = new Calculator();
calculator.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}
楼主把上面的代码改改，就可以满足你的需求
[解决办法]
给你个参考吧：
import java.awt.*;import javax.swing.*;public class TestGridBagLayout extends JFrame { public TestGridBagLayout() { GridBagLayout gbl = new GridBagLayout(); this.setSize(800, 300); this.setLayout(gbl); this.setDefaultCloseOperation(EXIT_ON_CLOSE); // Dfine GridBagConstraints GridBagConstraints gbc = new GridBagConstraints(); gbc.fill = GridBagConstraints.BOTH; gbc.weighty = 1; // Left Panel gbc.weightx = 0.3; // 30% JPanel panLeft = new JPanel(new BorderLayout()); panLeft.add(new JButton("panLeft"), BorderLayout.CENTER); gbl.setConstraints(panLeft, gbc); this.add(panLeft); // Center Panel gbc.fill = GridBagConstraints.VERTICAL; gbc.weightx = 0; // Fixed JPanel panMid = new JPanel(new BorderLayout()); panMid.setMinimumSize(new Dimension(100, 50)); panMid.setPreferredSize(new Dimension(100, 50)); panMid.add(new JButton("panMid"), BorderLayout.CENTER); gbl.setConstraints(panMid, gbc); this.add(panMid); // Right Panel gbc.fill = GridBagConstraints.BOTH; gbc.weightx = 0.7; // 70% JPanel panRight = new JPanel(new BorderLayout()); panRight.add(new JButton("panRight"), BorderLayout.CENTER); gbl.setConstraints(panRight, gbc); this.add(panRight); } public static void main(String[] args) { TestGridBagLayout wnd = new TestGridBagLayout(); wnd.setVisible(true); }}
[解决办法]
用GridBagConstraints作为约束来添加控件，可以达到要求的