我正在编写一个原型(prototype),但遇到了 GUI 问题。 我希望 JPanel pCustomer 居中,但这样做它会完全消失。例如,如果我把它放在南方,一切都很好。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Test extends JPanel implements ActionListener {
private JPanel pTop = new JPanel();
private JPanel pMenue = new JPanel();
private JPanel pContent = new JPanel();
private JPanel pCustomer = new JPanel();
private JPanel pEnq = new JPanel();
private JPanel pCustomerMenue = new JPanel();
private JTextField tf1 = new JTextField();
private JButton bCustomer = new JButton("Customer");
private JButton bEnq = new JButton("Product");
private JButton bCNew = new JButton("New Customer");
private JLabel lCustomer = new JLabel("Customer");
String[] customerString = {"--- SELECT -- ", "New Customer", "Edit Customer", "Delete Customer"};
private JComboBox cb1 = new JComboBox(customerString);
private JLabel lRes = new JLabel();
String[] productString = {"--- SELECT -- ", "Sell Product", "Enquire Product", "Complain Product"};
private JLabel lWelcome = new JLabel("Welcome to our System!");
private JLabel lNo = new JLabel("Customer Number: ");
private JLabel lEnq = new JLabel("Enquiry");
public Test() {
this.setLayout(new BorderLayout());
// pTop
this.add(pTop, BorderLayout.NORTH);
pTop.setLayout(new BorderLayout());
pTop.add(lNo, BorderLayout.WEST);
pTop.add(tf1, BorderLayout.CENTER);
// pMenue
this.add(pMenue, BorderLayout.WEST);
pMenue.setLayout(new GridLayout(5, 1));
pMenue.add(bCustomer);
pMenue.add(bEnq);
// pContent
this.add(pContent, BorderLayout.CENTER);
pContent.add(lWelcome);
pContent.setLayout(new BorderLayout());
pContent.setBackground(Color.GREEN);
// pCustomer
pContent.add(pCustomer, BorderLayout.CENTER); // EAST, SOUTH, WEST works, but I want it to be centered.
pCustomer.add(cb1);
pCustomer.add(lRes);
pCustomer.setVisible(false);
pCustomer.setBackground(Color.blue);
// pCustomerMenue
pContent.add(pCustomerMenue, BorderLayout.NORTH);
pCustomerMenue.add(bCNew);
pCustomerMenue.setVisible(false);
pCustomerMenue.setBackground(Color.red);
// pEnq
pContent.add(pEnq, BorderLayout.CENTER);
pEnq.add(lEnq);
pEnq.setVisible(false);
// ---
bCustomer.addActionListener(this);
bEnq.addActionListener(this);
}
@Override
public void actionPerformed(ActionEvent e) {
Object source = e.getSource();
lWelcome.setVisible(false);
if (source == bCustomer) {
init();
pCustomer.setVisible(true);
pCustomerMenue.setVisible(true);
bCustomer.setEnabled(false);
}
if (source == bEnq) {
init();
pEnq.setVisible(true);
bEnq.setEnabled(false);
}
}
public void init() {
pCustomer.setVisible(false);
pCustomerMenue.setVisible(false);
pEnq.setVisible(false);
bCustomer.setEnabled(true);
bEnq.setEnabled(true);
}
}
如果我删除这 3 行:
pContent.add(pEnq, BorderLayout.CENTER);
pEnq.add(lEnq);
pEnq.setVisible(false);
我什至可以将它放在中心,而且效果很好。
最佳答案
阅读有关边框布局的信息。基本上你有 5 个位置(北、东、南、西、中心),每当你将一个组件放在这些位置之一时,任何已经在该位置的组件都会被替换。
因此 pContent.add(pEnq, BorderLayout.CENTER);
将用 pEnq
替换 pCustomer
。
如果您希望两个面板都位于中心,您需要将一个中间面板放在中心,然后将其他面板添加到该面板,或者使用另一个布局管理器,例如MiGLayout
.
使用 MiGLayout
,您的 pContent
布局可能如下所示:
pContent.setLayout(new MiGLayout());
pContent.add(pCustomerMenue, "pushx, wrap"); //fill the available width, new line after this component
pContent.add(pCustomer, "pushx, wrap"); //fill the available width, new line after this component
pContent.add(pEnq, "pushx"); //fill the available width
关于java - BorderLayout.CENTER "disappears",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/8669162/