missice's Blog

將JTextField輸入的字串，轉為JComboBox元件的選項，
選項字串不可重複，再將JComboBox元件選到的選項顯示在JLabel元件上。

import javax.swing.SwingUtilities;
import javax.swing.JPanel;
import javax.swing.JFrame;
import javax.swing.JLabel;
import java.awt.Rectangle;
import javax.swing.JComboBox;
import javax.swing.JTextField;
import javax.swing.JButton;

public class test extends JFrame {

	private static final long serialVersionUID = 1L;
	private JPanel jContentPane = null;
	private JLabel lblResult = null;
	private JComboBox cbxList = null;
	private JTextField txtInput = null;
	private JButton btnAdd = null;

	private JComboBox getCbxList() {
		if (cbxList == null) {
			cbxList = new JComboBox();
			cbxList.setBounds(new Rectangle(49, 21, 81, 27));
			cbxList.addItemListener(new java.awt.event.ItemListener() {
				public void itemStateChanged(java.awt.event.ItemEvent e) {
					lblResult.setText(cbxList.getSelectedItem().toString());
				}
			});
		}
		return cbxList;
	}

	private JTextField getTxtInput() {
		if (txtInput == null) {
			txtInput = new JTextField();
			txtInput.setBounds(new Rectangle(51, 79, 83, 22));
		}
		return txtInput;
	}

	private JButton getBtnAdd() {
		if (btnAdd == null) {
			btnAdd = new JButton();
			btnAdd.setBounds(new Rectangle(176, 77, 62, 23));
			btnAdd.setText("add");
			btnAdd.addMouseListener(new java.awt.event.MouseAdapter() {
				public void mouseClicked(java.awt.event.MouseEvent e) {
					boolean flag=true;
					for (int i=0;i						if (txtInput.getText().equals(cbxList.getItemAt(i))){
							flag = false;
							break;
						}
					}
					if (flag){
						cbxList.addItem(txtInput.getText());
					}
				}
			});
		}
		return btnAdd;
	}

	public static void main(String[] args) {
		SwingUtilities.invokeLater(new Runnable() {
			public void run() {
				test thisClass = new test();
				thisClass.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
				thisClass.setVisible(true);
			}
		});
	}

	public test() {
		super();
		initialize();
	}

	private void initialize() {
		this.setSize(300, 200);
		this.setContentPane(getJContentPane());
		this.setTitle("JFrame");
	}

	private JPanel getJContentPane() {
		if (jContentPane == null) {
			lblResult = new JLabel();
			lblResult.setBounds(new Rectangle(175, 21, 67, 25));
			lblResult.setText("");
			jContentPane = new JPanel();
			jContentPane.setLayout(null);
			jContentPane.add(lblResult, null);
			jContentPane.add(getCbxList(), null);
			jContentPane.add(getTxtInput(), null);
			jContentPane.add(getBtnAdd(), null);
		}
		return jContentPane;
	}
}