Question

我有一个主框架类和两个面板类。

其中一个面板具有输入字段第二个面板有按钮

我试图弄清楚如何设置事件处理，以便单击第二个面板中的按钮时，我能够执行需要从第一个面板访问组件（文本字段）的操作。

问题是我无法访问其他类中的组件

代码：

public class MainFrame extends JFrame {

private InputPanel input_panel;
private ButtonPanel button_panel;

public MainFrame() {
   setTitle("Shop"); 
   setSize(650,350);
   setLocationRelativeTo(null);
   setResizable(false);
   setDefaultCloseOperation(EXIT_ON_CLOSE);

   input_panel = new InputPanel();
   button_panel = new ButtonPanel();

   add(input_panel, BorderLayout.CENTER);
   add(button_panel, BorderLayout.SOUTH);

   setVisible(true);
}

}

public class InputPanel extends JPanel {

private static JLabel item_num;
private static JLabel book_id;
private static JLabel quantity;
private static JLabel item_info;
private static JLabel subtotal;

private static JTextField t_item_num;
private static JTextField t_book_id;
private static JTextField t_quantity;
private static JTextField t_item_info;
private static JTextField t_subtotal;


public InputPanel() {

   //Layout Manager 
   FlowLayout flow_input_layout = new FlowLayout(FlowLayout.TRAILING, 75, 10);

   //Panel
   setLayout(flow_input_layout);
   setBackground(Color.yellow);

   //Text Fields and Labels
   item_num = new JLabel("Enter number of items in this order:");
   add(item_num);
   t_item_num = new JTextField(20);
   add(t_item_num);

   book_id = new JLabel("Enter Book ID for Item # 1:");
   add(book_id);
   t_book_id = new JTextField(20);
   add(t_book_id);

   quantity = new JLabel("Enter quantity for Item # 1:");
   add(quantity);
   t_quantity = new JTextField(20);
   add(t_quantity);

   item_info = new JLabel("Item # 1 Info:");
   add(item_info);
   t_item_info = new JTextField(20);
   add(t_item_info);

   subtotal = new JLabel("Order subtotal for X Items:");
   add(subtotal);
   t_subtotal = new JTextField(20);
   add(t_subtotal);
}

}

public class ButtonPanel extends JPanel implements ActionListener {

private static JButton process_btn;
private static JButton confirm_btn;
private static JButton view_btn;
private static JButton finish_btn;
private static JButton new_btn;
private static JButton exit_btn;

public  ButtonPanel() {

   //Layout Manager
   FlowLayout flow_input_layout = new FlowLayout();

   //Button Panel
   setLayout(flow_input_layout);
   setBackground(Color.blue);

   //Buttons
   process_btn = new JButton("Process Item #1");
   process_btn.addActionListener(this);
   add(process_btn);

   confirm_btn = new JButton("Confirm Item #1");
   confirm_btn.addActionListener(this);
   add(confirm_btn);

   view_btn = new JButton("View Order");
   view_btn.addActionListener(this);
   add(view_btn);

   finish_btn = new JButton("Finish Order");
   finish_btn.addActionListener(this);
   add(finish_btn);

   new_btn = new JButton("New Order");
   new_btn.addActionListener(this);
   add(new_btn);

   exit_btn = new JButton("Exit");
   exit_btn.addActionListener(this);
   add(exit_btn);
}

@Override
public void actionPerformed(ActionEvent event) {
    ;
}

}

问题是我无法从其他面板类访问组件。不知道该怎么办

Answer 1

最简单的方法是将InputPanel添加到ButtonPanel的构造函数中，然后将其存储在变量中。

input_panel = new InputPanel();
button_panel = new ButtonPanel(input_panel);

在ButtonPanel中：

public class ButtonPanel extends JPanel implements ActionListener {

...
private final InputPanel inputPanel;

public  ButtonPanel(final InputPanel inputPanel) {
    this.inputPanel = inputPanel;
    ...
}

@Override
public void actionPerformed(ActionEvent event) {
    this.inputPanel.getItemNum().doSomething() // you will need to also create accessor methods in the inputPanel
}

顺便说一句，您应该在Java中使用camelCase。

类之间的Java Swing事件处理

1 个答案: