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--- swing:combo_box [2018/03/27 17:09] – [Νon-editable combo box] gthanos
+++ swing:combo_box [Unknown date] (current) – external edit (Unknown date) 127.0.0.1
@@ Line 20: / Line 20: @@
 Παρακάτω δίνονται δύο παραδείγματα από το site της Oracle, ένα για //non-editable// combo box και ένα για //editable// combo box.
-==== Νon-editable combo box ====
+===== Νon-editable combo box =====
 <code java ComboBoxDemo.java>
 import java.awt.*;
 import java.awt.event.*;
@@ Line 36: / Line 35: @@
  *   images/Pig.gif
  */
+@SuppressWarnings({"serial", "unchecked"})
 public class ComboBoxDemo extends JPanel
               implements ActionListener {
@@ Line 47: / Line 47: @@
     //Create the combo box, select the item at index 4.
     //Indices start at 0, so 4 specifies the pig.
-    JComboBox petList = new JComboBox(petStrings);
+    JComboBox<String> petList = new JComboBox<>(petStrings);
     petList.setSelectedIndex(4);
     petList.addActionListener(this);
@@ Line 71: / Line 71: @@
   /** Listens to the combo box. */
   public void actionPerformed(ActionEvent e) {
-    JComboBox cb = (JComboBox)e.getSource();
+    JComboBox<String> cb = (JComboBox<String>)e.getSource();
     String petName = (String)cb.getSelectedItem();
     updateLabel(petName);
@@ Line 77: / Line 77: @@
   protected void updateLabel(String name) {
-    ImageIcon icon = createImageIcon(name + ".gif");
+    ImageIcon icon = new ImageIcon(name + ".gif");
     picture.setIcon(icon);
     picture.setToolTipText("A drawing of a " + name.toLowerCase());
@@ Line 84: / Line 84: @@
     } else {
       picture.setText("Image not found");
-    }
-  }
-  /** Returns an ImageIcon, or null if the path was invalid. */
-  protected static ImageIcon createImageIcon(String path) {
-    java.net.URL imgURL = ComboBoxDemo.class.getResource(path);
-    if (imgURL != null) {
-      return new ImageIcon(imgURL);
-    } else {
-      System.err.println("Couldn't find file: " + path);
-      return null;
     }
   }
@@ Line 132: / Line 121: @@
 Το παραπάνω πρόγραμμα προϋποθέτει τις παρακάτω εικόνες {{:swing:animals.zip|}}.
-==== Εditable combo box ====
+===== Εditable combo box =====
 <code java ComboBoxDemo2.java>
@@ Line 264: / Line 253: @@
+| Προηγούμενο: [[:swing:lists | Λίστες - Η κλάση JList ]] | [[:toc | Περιεχόμενα ]] | Επόμενο: [[:swing:panels | Η κλάση JPanel ]] |