View source for Teams Winter 2011/team1/BlackBerry/Implement Delete Option

=== 7. Implement Delete Student option ===
7.1. In the <code>ViewStudentApp</code> implement <code>DeleteCommandHandler</code> by adding anonymous class:
 <source lang="java">
  deleteItem.setCommand(new Command(new CommandHandler(){
       public void execute(ReadOnlyCommandMetadata metadata, Object context) {
         Student student = (Student) _keywordFilterField.getSelectedElement();
         if (student != null) {                 
           String[] selections = {"Yes","Cancel"};
           Dialog deleteDialog = new Dialog("Are you sure you want to delete " + student.getName() + "?", selections, null, 0, null);
                 
           // Display the dialog and deletes the element from the list
           if(deleteDialog.doModal() == 0) {
              _studentList.deleteElement(student);
              Dialog.alert(student.getName() + " has been deleted!");
              }
           }
         }
      }));
 </source>
7.2. Add the <code>deleteElement()</code> method to the <code>StudentList</code> class:
 <source lang="java">
  void deleteElement(Object element) {
        doRemove(element);
    }
 </source>
7.3. Run the application, select one student and select "'''Delete Student'''" from the menu:<br/>
[[Image: BB_delete1.png | 300px]]<br/>
7.4. Click "'''Delete Student'''". A dialog box pop-ups asking to confirm the student deletion:<br/>
[[Image: BB_delete2.png | 300px]]<br/>
7.5. Select "'''Yes'''" Option. The dialog window comes up acknowledging that student is deleted:<br/>
[[Image: BB_delete3.png | 300px]]<br/>
7.6. Add "''Delete Student''" as option in view screen. Change the one argument constructor of the anonymous class to two argument constructor:
 <source lang="java">
  InfoScreen(final Student student, final StudentList studentList) {  }
 </source>
7.7. Add <code>MenuItem</code> to this screen menu and implement <code>CommandHandler</code>:
 <source lang="java">
  MenuItem deleteItem = new MenuItem(new StringProvider("Delete Student"), 400, 4);
  deleteItem.setCommand(new Command(new CommandHandler(){
      public void execute(ReadOnlyCommandMetadata metadata, Object context) {
                  
      if (student != null) {                 
        String[] selections = {"Yes","Cancel"};
        Dialog deleteDialog = new Dialog("Are you sure you want to delete " + student.getName() + "?", selections, null, 0, null);
                     
        // Display the dialog and deletes the element from the list
        if(deleteDialog.doModal() == 0) {
           studentList.deleteElement(student);
           Dialog.alert(student.getName() + " has been deleted!");
           close();
         }
        }
       }
   }));
   addMenuItem(deleteItem);
 </source>
7.8. Run the application, select a student and inside the View Screen go to the menu and select "'''Delete Student'''": <br/>
[[Image: BB_delete4.png | 300px]]<br/>
7.9. Repeat the same steps as for the Main Screen. When you are done you should be redirected to Main Screen.