在 Java 中使用字符串指定对象

Question

我有一个索引范围为 0-20 的组合 Bx（下拉框）。如果无论如何我可以使用该索引来指定我想要来自哪个对象的数据？所有对象都使用相同的命名约定 obj0、obj1、obj2 等。基本上是这样的......

public abstract class Person {

    private String name;
    private String title;
    private String email;
    private String job;

    public Person(String name, String title, String email, String job){
        this.name = name;
        this.title = title;
        this.email = email;
        this.job = job;
    }
    //Getters and Setters
}



public class main extends javax.swing.JFrame {
...misc code...

private void btn_startActionPerformed(java.awt.event.ActionEvent evt) {                                          

    Person obj0 = new Person("Jon Doe",
                             "Program Coordinator",
                             "jon.doe@test.com",
                             "Faculty");

    Person obj1 = ...
    ...
    Person obj20 = ...

/*
Onclick it uses the index of the current index in the combobox (dropdown)
to specify which object to get the data from.
*/
private void btn_GetActionPerformed(java.awt.event.ActionEvent evt) {

    //Uses the obj naming convention plus the index
    string foo = "obj" + toString(combobox_Name.getSelectedIndex());

    //Fills the textbox using the above string and the getName method
    txtbox_username.setText(ToObject(foo).getName);
}

Answer 1

我已经创建了我认为您想要的基本设计：

此代码创建 20 个对象，将它们添加到组合框，并在选择时使用它们的预定义名称来更改文本字段。

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.BoxLayout;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;

class ObjExample {

    String name;

    public ObjExample(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return name;
    }

}

public class Main extends JFrame implements ActionListener {

    JComboBox jcb = new JComboBox();
    JTextField jtf = new JTextField("Text Field");

    public Main() {

        setSize(200, 200);
        setDefaultCloseOperation(EXIT_ON_CLOSE);

        for (int i = 0; i <= 20; i++) {
            jcb.addItem(new ObjExample(Integer.toString(i)));
        }

        jcb.addActionListener(this);

        add(jcb);
        add(jtf);

        setVisible(true);
    }

    public static void main(String[] args) {
        new Main();
    }

    @Override
    public void actionPerformed(ActionEvent e) {

        if (e.getSource() == jcb) {
            ObjExample obj = (ObjExample) jcb.getSelectedItem();
            jtf.setText(obj.toString());
        }
    }

}