这是文件1(我的老师更愿意我们为每个扩展名使用单独的文件)
import javax.swing.*;
import java.awt.*;
public class Lab2 extends JFrame {
Lab2(){
setTitle("Lab 1b - Application #2");
Lab2Panel p = new Lab2Panel();
add(p);
}
public static void main(String[] args){
Lab2 frame = new Lab2();
frame.setTitle("Lab2 Application # 1");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 400);
frame.setVisible(true);
}
}
文件2:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Lab2Panel extends JPanel{
Lab2Button canvas = new Lab2Button();
JPanel panel = new JPanel();
Lab2Panel () {
setLayout(new BorderLayout());
JButton leftButton = new JButton("left");
JButton rightButton = new JButton("right");
JButton upButton = new JButton("up");
JButton downButton = new JButton("down");
panel.add(leftButton);
panel.add(rightButton);
panel.add(upButton);
panel.add(downButton);
this.add(canvas, BorderLayout.CENTER);
this.add(panel, BorderLayout.SOUTH);
leftButton.addActionListener(new Lab2MoveBallListener());
}
}
文件3:
import javax.swing.*;
import java.awt.*;
public class Lab2Button extends JPanel {
int radius = 5;
protected void paintComponent(Graphics g){
super.paintComponent(g);
g.drawOval(getWidth() / 2 - radius, getHeight() / 2 - radius, 2 * radius, 2 * radius);
}
public void moveLeft(){
this.add(this, BorderLayout.WEST);
this.repaint();
}
}
动作侦听器代码:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Lab2MoveBallListener implements ActionListener{
public void actionPerformed(ActionEvent e){
this.moveLeft();
}
}
当用户单击“左”按钮时,我试图将圆移动到WEST边框布局。有谁可以帮助我吗。
最佳答案
我不确定我是否知道此GUI应该做什么,但这可以将圆向左移动。我的意见的第3点和第4点仍然需要解决。
这是修改后的代码。
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class Lab2 extends JFrame {
Lab2(){
setTitle("Lab 1b - Application #2");
Lab2Panel p = new Lab2Panel();
add(p);
}
public static void main(String[] args){
Lab2 frame = new Lab2();
frame.setTitle("Lab2 Application # 1");
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(200, 400);
frame.setVisible(true);
}
}
class Lab2Panel extends JPanel{
Lab2Button canvas = new Lab2Button();
JPanel panel = new JPanel();
Lab2Panel () {
setLayout(new BorderLayout());
JButton leftButton = new JButton("left");
JButton rightButton = new JButton("right");
JButton upButton = new JButton("up");
JButton downButton = new JButton("down");
panel.add(leftButton);
panel.add(rightButton);
panel.add(upButton);
panel.add(downButton);
this.add(canvas, BorderLayout.CENTER);
this.add(panel, BorderLayout.SOUTH);
leftButton.addActionListener(new Lab2MoveBallListener(canvas));
}
}
class Lab2Button extends JPanel {
int radius = 5;
int x = -1;
int y = -1;
protected void paintComponent(Graphics g){
if (x<0 || y<0) {
x = getWidth() / 2 - radius;
y = getHeight() / 2 - radius;
}
super.paintComponent(g);
g.drawOval(x,y, 2 * radius, 2 * radius);
}
public void moveLeft(){
//this.add(this, BorderLayout.WEST);
x -= 5;
this.repaint();
}
}
class Lab2MoveBallListener implements ActionListener{
private Lab2Button canvas;
Lab2MoveBallListener(Lab2Button canvas) {
this.canvas = canvas;
}
public void actionPerformed(ActionEvent e){
canvas.moveLeft();
}
}
..如何区分所执行动作中的按钮?
有很多方法。
ActionEvent.getActionCommand()
/ getSource()
与if
/ else
语句一起选择正确的操作。将单独的侦听器添加到每个按钮。这在现实世界的代码中更为常见。不需要获取源代码或检查操作命令。