如何從一個類調用鏈表到另一個類？

Question

我有一個問題，它是通過從另一個鏈表調用一個鏈表。 我不知道如何調用 CustomerPark 類並將元素放入文本字​​段。

這是我的第一堂課

package assignment_parking_2;

import java.util.*;

public class Parking{
public static void main(String[]args){
    LinkedList<String> customers = new LinkedList<String>();
    Scanner scan = new Scanner(System.in); 
    int choice=0; 
    do{
        //for(int i=0; i<=25; i++){
       System.out.println("\nRentable Parking Space"); 
       System.out.println("[1]Park a Car"); 
       System.out.println("[2]Leave"); 
       System.out.println("[3]View Parking Lot"); 
       System.out.println("[4]Exit"); 

       System.out.println("Enter choice"); 
       choice = scan.nextInt(); 
       switch(choice){ 
          case 1: 
             System.out.println("Insert your plate number: "); 
             String platenos = scan.next(); 
             customers.addLast(platenos); 
             break;
          case 2: 
             System.out.println("Your customer who has a plate number " +customers.removeFirst()+ " has already left!");
        break;
          case 3: 
             System.out.println("There are " +customers.size()+ " customer/s in the line.");
             CustomerPark viewPark = new CustomerPark();
             viewPark.main(args);
                 int index = 0;
                 while(index<customers.size()){
                 System.out.print("||" + customers.get(index));
                     index+=1;
             }
             break;
          case 4: 
              System.out.println("Thank you for using the System. The system will now exit.");
              break;
           default: 
              System.out.println("You have made an invalid choice, please choose again.");
        }
    // }System.out.println("Sorry the parking space is already full!");
    }
     while(choice!=4);

} }

還有我的第二堂課

package assignment_parking_2;

import java.awt.*;

import javax.swing.*;
import java.util.*;

公共類 CustomerPark 擴展 JFrame {

private JPanel contentPane;
private JTextField textField;
private JTextField textField_1;
private JTextField textField_2;
private JTextField textField_3;
private JTextField textField_4;
private JTextField textField_5;
private JTextField textField_6;
private JTextField textField_7;
private JTextField textField_8;
private JTextField textField_9;
private JTextField textField_10;
private JTextField textField_11;
private JTextField textField_12;
private JTextField textField_13;
private JTextField textField_14;
private JTextField textField_15;
private JTextField textField_16;
private JTextField textField_17;
private JTextField textField_18;
private JTextField textField_19;
private JTextField textField_20;
private JTextField textField_21;
private JTextField textField_22;
private JTextField textField_23;
private JTextField textField_24;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                CustomerPark frame = new CustomerPark();
                frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the frame.
 */
public CustomerPark() {
    setResizable(false);
    setTitle("View Parking Lot");
    setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
    setBounds(100, 100, 358, 360);
    contentPane = new JPanel();
    contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
    setContentPane(contentPane);
    contentPane.setLayout(null);


    textField = new JTextField();
    textField.setEditable(false);
    textField.setBounds(21, 11, 52, 50);
    contentPane.add(textField);
    textField.setColumns(10);

    textField_1 = new JTextField();
    textField_1.setEditable(false);
    textField_1.setBounds(83, 11, 52, 50);
    contentPane.add(textField_1);
    textField_1.setColumns(10);

    textField_2 = new JTextField();
    textField_2.setEditable(false);
    textField_2.setBounds(145, 11, 52, 50);
    contentPane.add(textField_2);
    textField_2.setColumns(10);

    textField_3 = new JTextField();
    textField_3.setEditable(false);
    textField_3.setBounds(207, 11, 52, 50);
    contentPane.add(textField_3);
    textField_3.setColumns(10);

    textField_4 = new JTextField();
    textField_4.setEditable(false);
    textField_4.setBounds(268, 11, 52, 50);
    contentPane.add(textField_4);
    textField_4.setColumns(10);

    textField_5 = new JTextField();
    textField_5.setEditable(false);
    textField_5.setBounds(21, 72, 52, 50);
    contentPane.add(textField_5);
    textField_5.setColumns(10);

    textField_6 = new JTextField();
    textField_6.setEditable(false);
    textField_6.setBounds(83, 72, 52, 50);
    contentPane.add(textField_6);
    textField_6.setColumns(10);

    textField_7 = new JTextField();
    textField_7.setEditable(false);
    textField_7.setBounds(145, 72, 52, 50);
    contentPane.add(textField_7);
    textField_7.setColumns(10);

    textField_8 = new JTextField();
    textField_8.setEditable(false);
    textField_8.setBounds(207, 72, 52, 50);
    contentPane.add(textField_8);
    textField_8.setColumns(10);

    textField_9 = new JTextField();
    textField_9.setEditable(false);
    textField_9.setBounds(268, 72, 52, 50);
    contentPane.add(textField_9);
    textField_9.setColumns(10);

    textField_10 = new JTextField();
    textField_10.setEditable(false);
    textField_10.setBounds(21, 133, 52, 50);
    contentPane.add(textField_10);
    textField_10.setColumns(10);

    textField_11 = new JTextField();
    textField_11.setEditable(false);
    textField_11.setBounds(83, 133, 52, 50);
    contentPane.add(textField_11);
    textField_11.setColumns(10);

    textField_12 = new JTextField();
    textField_12.setEditable(false);
    textField_12.setBounds(145, 133, 52, 50);
    contentPane.add(textField_12);
    textField_12.setColumns(10);

    textField_13 = new JTextField();
    textField_13.setEditable(false);
    textField_13.setBounds(207, 133, 52, 50);
    contentPane.add(textField_13);
    textField_13.setColumns(10);

    textField_14 = new JTextField();
    textField_14.setEditable(false);
    textField_14.setBounds(268, 133, 52, 50);
    contentPane.add(textField_14);
    textField_14.setColumns(10);

    textField_15 = new JTextField();
    textField_15.setEditable(false);
    textField_15.setBounds(21, 194, 52, 50);
    contentPane.add(textField_15);
    textField_15.setColumns(10);

    textField_16 = new JTextField();
    textField_16.setEditable(false);
    textField_16.setBounds(83, 194, 52, 50);
    contentPane.add(textField_16);
    textField_16.setColumns(10);

    textField_17 = new JTextField();
    textField_17.setEditable(false);
    textField_17.setBounds(145, 194, 52, 50);
    contentPane.add(textField_17);
    textField_17.setColumns(10);

    textField_18 = new JTextField();
    textField_18.setEditable(false);
    textField_18.setBounds(207, 194, 52, 50);
    contentPane.add(textField_18);
    textField_18.setColumns(10);

    textField_19 = new JTextField();
    textField_19.setEditable(false);
    textField_19.setBounds(268, 194, 52, 50);
    contentPane.add(textField_19);
    textField_19.setColumns(10);

    textField_20 = new JTextField();
    textField_20.setEditable(false);
    textField_20.setBounds(21, 255, 52, 50);
    contentPane.add(textField_20);
    textField_20.setColumns(10);

    textField_21 = new JTextField();
    textField_21.setEditable(false);
    textField_21.setBounds(83, 255, 52, 50);
    contentPane.add(textField_21);
    textField_21.setColumns(10);

    textField_22 = new JTextField();
    textField_22.setEditable(false);
    textField_22.setBounds(145, 255, 52, 50);
    contentPane.add(textField_22);
    textField_22.setColumns(10);

    textField_23 = new JTextField();
    textField_23.setEditable(false);
    textField_23.setBounds(207, 255, 52, 50);
    contentPane.add(textField_23);
    textField_23.setColumns(10);

    textField_24 = new JTextField();
    textField_24.setEditable(false);
    textField_24.setBounds(268, 255, 52, 50);
    contentPane.add(textField_24);
    textField_24.setColumns(10);



}

}

我希望你能幫助我。 謝謝！！

Answer 1

您的主要問題是您試圖將單個靜態主方法程序與 Swing GUI 結合在一起，但這根本行不通，因為它是混合油和水的編程等價物。 將您的頂級類重寫為符合 OOP 的類，具有非靜態私有字段和公共非靜態方法（例如，具有“狀態”和“行為”），並將其用作大腦或“模型”您的 GUI（“視圖”）。 主要方法應該很短，應該足以創建模型並將其與視圖連接起來，就是這樣。

因此，這也意味着您不希望使用 Scanner 和 System.in 獲取用戶輸入，而是創建通過 GUI 獲取用戶輸入的代碼，因為線性控制台/掃描儀代碼也不適用於事件驅動的 GUI代碼。

其他問題——是的，擺脫所有不必要的冗余，因為它會使維護、調試和增強這個程序成為一場徹頭徹尾的噩夢。

請注意，您通過方法和構造函數將信息從一個類傳遞到另一個類。 例如，如果您為 CustomerPark 構造函數提供了 LinkedList 參數，則可以在創建時將該信息傳遞到類中。

例如，您可以使用 JTextField 的 2D 數組並將它們填充到接收 LinkedList 的構造函數中。

public CustomerPark(List<String> customerList) {
    setLayout(new GridLayout(ROWS, COLS, GAP, GAP));
    for (int r = 0; r < textFields.length; r++) {
        for (int c = 0; c < textFields[r].length; c++) {
            textFields[r][c] = new JTextField(TF_COLS);
            textFields[r][c].setEditable(false);
            textFields[r][c].setFont(TF_FONT);
            textFields[r][c].setText(customerList.remove(0));
            add(textFields[r][c]);
        }
    }
}