Java Swing How to - Allow JComboBox to accept List or HashMap instead of String[]








Question

We would like to know how to allow JComboBox to accept List or HashMap instead of String[].

Answer

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import java.util.ArrayList;
import java.util.Arrays;
// www .j av a 2s .  com
import javax.swing.JComboBox;
import javax.swing.JFrame;

public class Main extends JFrame {
  public Main() {

    super();
    java.util.List<String> list = new ArrayList<String>();

    list.add("A");
    list.add("B");
    list.add("C");
    list.add("D");

    Object[] arrayObject = list.toArray();
    String[] data = Arrays.copyOf(arrayObject, arrayObject.length,
        String[].class); // java 1.6+
    JComboBox<String> combo = new JComboBox<>(data);

    setLayout(new FlowLayout(FlowLayout.CENTER));
    add(combo, BorderLayout.CENTER);
  }

  public static void main(String[] args) {
    Main g = new Main();
    g.setVisible(true);
    g.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    g.setBounds(100, 100, 300, 300);
  }
}