Question

java BorderLayout布局程序问题，按钮不起作用啊。。。求指导。。。

import java.awt.*;
import java.awt.event.*;
class WindowButton extends Frame implements ActionListener {
Button bSouth;
Button bNorth;
Button bWest;
TextArea bCenter;
WindowButton(String s)
{
super(s);
setLayout(new BorderLayout());
Button bSouth=new Button("标点");
Button bNorth=new Button("中文");
Button bWest=new Button("英文");
TextArea bCenter=new TextArea();
add(bSouth,BorderLayout.SOUTH);
add(bNorth,BorderLayout.NORTH);
add(bWest,BorderLayout.WEST);
add(bCenter,BorderLayout.CENTER);
bSouth.addActionListener(this);
bNorth.addActionListener(this);
bWest.addActionListener(this);
setBounds(100, 100, 300, 300);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e) {
if(e.getSource()==bNorth)
{
bCenter.setText("你按了中文按钮");
}
else if(e.getSource()==bSouth)
{
bCenter.setText(",.!");
}
else if(e.getSource()==bWest)
{
bCenter.setText("You type the English button");
}
}
}
public class Hello
{
public static void main(String[] args) {
WindowButton win=new WindowButton("按钮小练习");
}

}

Answer 1

你的程序是有点问题，我主要修改了两个地方：

import java.awt.*;
import java.awt.event.*;
class WindowButton extends Frame implements ActionListener {
Button bSouth;
Button bNorth;
Button bWest;
TextArea bCenter;

WindowButton(String s)
{
super(s);
setLayout(new BorderLayout());
Button bSouth=new Button("标点");
Button bNorth=new Button("中文");
Button bWest=new Button("英文");
bCenter=new TextArea(); //修改第1处
add(bSouth,BorderLayout.SOUTH);
add(bNorth,BorderLayout.NORTH);
add(bWest,BorderLayout.WEST);
add(bCenter,BorderLayout.CENTER);
bSouth.addActionListener(this);
bNorth.addActionListener(this);
bWest.addActionListener(this);
setBounds(100, 100, 300, 300);
setVisible(true);
validate();
}
public void actionPerformed(ActionEvent e) {
Button btn = (Button)e.getSource(); //修改第2处
if(btn.getLabel().equals("中文"))
{
bCenter.setText("你按了中文按钮");
}
if(btn.getLabel().equals("标点"))
{
bCenter.setText(",.!");
}
else if(btn.getLabel().equals("英文"))
{
bCenter.setText("You type the English button");
}
}
}
public class Hello
{
public static void main(String[] args) {
WindowButton win=new WindowButton("按钮小练习");
}
}

Answer 2

注意，setLayout(null)后，java将不再管理组件的布局，都需要你自己操心了。我记得好像是先定义panel，在右边定义它，定义按钮是选择 Xy。什么的我

追问

不是布局问题，就是按钮按了它不显示，不起作用。。。怎么回事呢？

Answer 3

e.getSource 返回值是button吗?
不知道,
但对象之间相等应用equals()