import java.awt.event.*;

import javax.swing.*;

public class BaglantiliCombo {

	public BaglantiliCombo() {
		
		JFrame frame = new JFrame("Baglantili JComboBox Ornegi Java Blackboard 059");
		frame.setLayout(null);
		
		String[] diziSehir = { "Şehir Seçiniz", "İstanbul", "Ankara", "Antalya", "Muğla"};        
	    
		JLabel labelBaslik = new JLabel("Bağlantılı ComboBox ÖRNEK");
		labelBaslik.setBounds(100, 50, 200, 30);
		
		JLabel labelSehir = new JLabel("Şehir : ");
		labelSehir.setBounds(100, 100, 50, 30);
		
		JComboBox comboSehir = new JComboBox(diziSehir);    
		comboSehir.setBounds(150, 100, 150,30);
		
		JLabel labelIlce = new JLabel("İlçe : ");
		labelIlce.setBounds(100, 150, 50, 30);
		
		JComboBox comboIlce = new JComboBox();    
		comboIlce.setBounds(150, 150, 150,30);
		
		JButton butonGoster = new JButton("Göster");
		butonGoster.setBounds(100, 200, 200, 30);
		
		JTextArea areaSecilenler = new JTextArea();
		areaSecilenler.setBounds(100, 250, 200, 200);
		
		JScrollPane areaPane = new JScrollPane(areaSecilenler);
		areaPane.setBounds(100, 250, 200, 200);
		
		comboSehir.addActionListener(new ActionListener() { 
			public void actionPerformed(ActionEvent e) {
				
				if (comboSehir.getSelectedItem().equals("İstanbul")) {

					comboIlce.removeAllItems();
					comboIlce.setSelectedItem(0);
					comboIlce.addItem("İlçe seçiniz.");  // 0
					comboIlce.addItem("Kadıköy"); // 1
					comboIlce.addItem("Üsküdar");
					comboIlce.addItem("Eminönü");
					comboIlce.addItem("Beşiktaş");
				
				} else if ( comboSehir.getSelectedItem().equals("Ankara")) {

					comboIlce.removeAllItems();
					comboIlce.setSelectedItem(0);
					comboIlce.addItem("İlçe seçiniz.");
					comboIlce.addItem("Gölbaşi");
					comboIlce.addItem("Altındağ");
					comboIlce.addItem("Beypazarı");
					comboIlce.addItem("Keçiören");
				
				} else if ( comboSehir.getSelectedItem().equals("Antalya")) {

					comboIlce.removeAllItems();
					comboIlce.setSelectedItem(0);
					comboIlce.addItem("İlçe seçiniz.");
					comboIlce.addItem("Kemer");
					comboIlce.addItem("Manavgat");
					comboIlce.addItem("Muratpaşa");
					comboIlce.addItem("Konyaaltı");
				
				} else if ( comboSehir.getSelectedItem().equals("Muğla")) {

					comboIlce.removeAllItems();
					comboIlce.setSelectedItem(0);
					comboIlce.addItem("İlçe seçiniz.");
					comboIlce.addItem("Bodrum");
					comboIlce.addItem("Datça");
					comboIlce.addItem("Dalaman");
					comboIlce.addItem("Fethiye");
					comboIlce.addItem("Milas");
				
				}
				
				
				
			}
			
		});           
		
		butonGoster.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                
            	String sehirAdi = (String) comboSehir.getSelectedItem();
            	comboSehir.setSelectedIndex(0);
            	
            	String ilceAdi = (String) comboIlce.getSelectedItem();
            	comboIlce.setSelectedIndex(0);
            	
            	//	String squareSymbol = new String(Character.toChars(0x25A0)); // ■ -> https://unicode-table.com/en/25A0/
            	String squareSymbol = "\u25A0"; // ■ -> https://unicode-table.com/en/25A0/
            	
				areaSecilenler.append(squareSymbol+squareSymbol+squareSymbol+"\nSeçilen şehir ve ilçe bilgisi:\nŞehir : "+ sehirAdi + "\nİlçe : " + ilceAdi + "\n");
            	
				
            }
        });
		
		frame.add(labelBaslik);
		
		frame.add(labelSehir);
		frame.add(comboSehir);
		
		frame.add(labelIlce);
		frame.add(comboIlce);
		
		frame.add(butonGoster);
		
		frame.add(areaPane);
		
		frame.setSize(400, 500);
		frame.setLocationRelativeTo(null);
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		frame.setVisible(true);
	}
}