Action Listener中的Action Listener

Question

我正在为一个学校项目创建一台自动售货机，当用户点击A1、A2、B1、B2等时，我必须更新数字。小数点后的所有内容都会更改，但小数之前的所有内容都不会更改。因此，如果我单击A1，它设置为4美元50美分，然后我选择D4，它是1美元5美分，我的JTextField显示为4美元5美分。

以下是GUI上的按钮：

​

​

this is for buttons A and B

for buttons C and D

public void cost() {
    
     C_button.addActionListener (new ActionListener () {
         public void actionPerformed (ActionEvent e) {
          button_1.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.5;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_2.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.25;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_3.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.10;
                cost_total.setText(String.valueOf(total_order));

             }
            });
          button_4.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 2 + 0.05;
                cost_total.setText(String.valueOf(total_order));

             }
            });
         } 
        });

       D_button.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
              button_1.addActionListener (new ActionListener () {
                 public void actionPerformed (ActionEvent e) {
                    total_order = 1 + 0.5;
                    cost_total.setText(String.valueOf(total_order));

                 }
                });
              button_2.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.25;
                cost_total.setText(String.valueOf(total_order));

             }
            });
              button_3.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.10;
                cost_total.setText(String.valueOf(total_order));

             }
            });
              button_4.addActionListener (new ActionListener () {
             public void actionPerformed (ActionEvent e) {
                total_order = 1 + 0.05;
                cost_total.setText(String.valueOf(total_order));

             }
            });
             }
            });

Answer 1

你让这件事变得比原来更难了。首先，我将创建所有价值组合及其成本的映射，如下所示：

Map<String, Double> costMap = new HashMap<>();
costMap.put("A1", 4.5);
costMap.put("A2", 4.25);

然后我会在某个地方创建一个字符串来跟踪用户输入：

String register = "";

然后创建一个Action来处理为您的大部分键按下的基本键：

public class VendingAction extends AbstractAction {
    @Override
    public void actionPerformed(ActionEvent arg0) {
        register += getValue(Action.NAME);
        if (costMap.containsKey(register)) {
            costLabel.setText(costMap.get(register).toString());
            register = "";
        } else if (register.length() == 2) {
            //handle bad choice
            register = "";
        }
    }
}

然后，当你创建你的按钮时，它应该是这样的：

JButton buttonA = new JButton(new VendingAction("A"));
JButton buttonB = new JButton(new VendingAction("B"));
//so on and so forth.