正如标题所说，我想从不同的类中提取一些变量。在课堂上，我的任务是制作一个不是特别难编码的魔方块，所以我想我会制作一个交互式 GUI，因为在我必须学习如何使用 JLabel 和 JButton 等之前，我从未使用 GUI 编码过。
我相信我自己成功地学习了这个，能够想出一个带有不同部分的对话框，打开一个提示菜单，但是我添加了一个确认按钮，我想显示用户输入的内容。我已经使用JOptionPane.showMessageDialog来获取用户输入并将其分配给一个变量，但是我不知道如何将变量从它的类中提取到主变量中，我可以将其用于其他目的。我尝试过使用它：classname.membername，但我无法让它工作。
代码如下：
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.*;
public class Magic_SquareR {
static boolean confirm = false;
public Magic_SquareR() {
gui();
}
public void gui() {
JFrame f = new JFrame();
f.setVisible(true);
f.setSize(350, 150);
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.setLayout(new FlowLayout());
JPanel p = new JPanel(new GridBagLayout());
JButton b1 = new JButton("ML");
JButton b2 = new JButton("TL");
JButton b3 = new JButton ("BL");
JButton b4 = new JButton ("TM");
JButton b5 = new JButton ("MM");
JButton b6 = new JButton ("BM");
JButton b7 = new JButton ("TR");
JButton b8 = new JButton ("MR");
JButton b9 = new JButton ("BR");
JButton b10 = new JButton ("Confirm");
GridBagConstraints c = new GridBagConstraints();
c.insets = new Insets(5,5,5,5);
c.gridx = 0;
c.gridy = 0;
p.add(b2,c);
b2.addActionListener(new Action());
c.gridx = 0;
c.gridy = 100;
p.add(b1,c);
b1.addActionListener(new Action2());
c.gridx = 0;
c.gridy = -100;
p.add(b3,c);
b3.addActionListener(new Action3());
c.gridx = 100;
c.gridy = 000;
p.add(b4,c);
b4.addActionListener(new Action4());
c.gridx = 100;
c.gridy = -100;
p.add(b5,c);
b5.addActionListener(new Action5());
c.gridx = 100;
c.gridy = -100;
p.add(b6,c);
b6.addActionListener(new Action6());
c.gridx = -100;
c.gridy = -100;
p.add(b7,c);
b7.addActionListener(new Action7());
c.gridx = 200;
c.gridy = -100;
p.add(b8,c);
b8.addActionListener(new Action8());
c.gridx = 200;
c.gridy = -100;
p.add(b9,c);
b9.addActionListener(new Action9());
c.gridx = 100;
c.gridy = 300;
p.add(b10,c);
b10.addActionListener(new Action10());
f.add(p);
}
static class Action implements ActionListener {
public void actionPerformed (ActionEvent e) {
String TL = JOptionPane.showInputDialog("Please enter a number from 1-10 for TL");
int tl = Integer.parseInt(TL);
}
}
static class Action2 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String ML = JOptionPane.showInputDialog("Please enter a number from 1-10 for ML");
int ml = Integer.parseInt(ML);
}
}
static class Action3 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String BL = JOptionPane.showInputDialog("Please enter a number from 1-10 for BL");
int bl = Integer.parseInt(BL);
}
}
static class Action4 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String TM = JOptionPane.showInputDialog("Please enter a number from 1-10 for TM");
int tm = Integer.parseInt(TM);
}
}
static class Action5 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String MM = JOptionPane.showInputDialog("Please enter a number from 1-10 for MM");
int mm = Integer.parseInt(MM);
}
}
static class Action6 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String BM = JOptionPane.showInputDialog("Please enter a number from 1-10 for BM");
int bm = Integer.parseInt(BM);
}
}
static class Action7 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String TR = JOptionPane.showInputDialog("Please enter a number from 1-10 for TR");
int tr = Integer.parseInt(TR);
}
}
static class Action8 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String MR = JOptionPane.showInputDialog("Please enter a number from 1-10 for MR");
int mr = Integer.parseInt(MR);
}
}
public class Action9 implements ActionListener {
public void actionPerformed (ActionEvent e) {
String BR = JOptionPane.showInputDialog("Please enter a number from 1-10 for BR");
int br = Integer.parseInt(BR);
}
}
public class Action10 implements ActionListener {
public void actionPerformed (ActionEvent e) {
JOptionPane.showMessageDialog(null, "Welcome to the end - This is where we check your answers");
JOptionPane.showMessageDialog(null, "For BR your wrote " + Action9.BR);
}
}
public static void main(String args[]) {
new Magic_SquareR();
{
}
您对当前值所做的只是将它们分配给局部变量(在方法返回后消失(。实现对它们的访问的最简单方法是将它们声明为类中的非静态变量Magic_SquareR。
public class Magic_SquareR {
static boolean confirm = false;
static int actionResult1;
//other results
public Magic_SquareR() {
gui();
}
public void gui() {
// ...
}
static class Action implements ActionListener {
public void actionPerformed (ActionEvent e) {
String TL = JOptionPane.showInputDialog("Please enter a number from 1-10 for TL");
Magic_SquareR.actionResult1 = Integer.parseInt(TL);
}
}
public static void main(String[] args) {
new Magic_SquareR();
System.out.println(actionResult1);
}
}
请注意，这确实是实现这一目标的"丑陋"方式(您通常应避免使用静态变量(，但它可以。
如果您希望在单独的文件中声明 Action 类更专业，请为它们提供带有输入值的局部变量，并从 gui(( 方法返回这些值的列表：
public class Action implements ActionListener {
int actionResult;
public void actionPerformed (ActionEvent e) {
String TL = JOptionPane.showInputDialog("Please enter a number from 1-10 for TL");
actionResult = Integer.parseInt(TL);
}
{
在 gui(( 中，它看起来像这样：
//return list of input values instead of void
List<Integer> gui() {
List<Integer> list = new ArrayList();
//...
c.gridx = 0;
c.gridy = 100;
p.add(b1,c);
//Assign action to variable so you can access it later
Action action = new Action();
b1.addActionListener(action);
list.add(action.actionResult);
//...
return list;
}