Teams Winter 2011/team1/BlackBerry/Add Elements to Main Screen

3. Add Elements on Main (First) Screen

3.1. Open MyScreen.java class.
3.2. Create class Student with the following fields:

    private String firstName;
    private String lastName;
    private String email;
 

3.3. Add three argument constructor:

  public Student(String firstName, String lastName, String email) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.email = email;
    }
 

3.4. Add getter method for e-mail and override the toString() from the Object class(it will be used to implement Comparator interface):

   public String getEmail() {
        return email;
    }
   
    public String toString() {
        return firstName + " " + lastName;
    }
 

3.5. Add class that will hold all Student objects and make necessary manipulations:

  public class StudentList extends SortedReadableList implements KeywordProvider {

    public StudentList(Vector students) {
        super(new StudentListComparator());   
        loadFrom(students.elements());  
    }

    /**
     * Adds a new element to the list.
     * @param element The element to be added.
     */
    void addElement(Object element) {
        doAdd(element);
    } 

    /**
     * A Comparator class used for sorting our Student objects by name.
     */
    final static class StudentListComparator implements Comparator {  
        /**
         * Compares two students by comparing their names in alphabetical order.
         * @see net.rim.device.api.util.Comparator#compare(Object, Object)
         */
        public int compare(Object o1, Object o2) {
            if (o1 == null || o2 == null) {
                throw new IllegalArgumentException("Cannot compare null students");
            }
            return o1.toString().compareTo(o2.toString());
        }       
    }

    public String[] getKeywords(Object element) {
        if(element instanceof Student )
        {           
            return StringUtilities.stringToWords(element.toString());
        } 
        return null;
    }  
}

 

3.6. The following elements are added to the MyScreen() constructor:

     // A reference to the UiApplication instance for use in this class
     _app = app;
     // Obtain a reference to the UiApplication's KeywordFilterField       
     _keywordFilterField = _app.getKeywordFilterField();
 

3.7. Other elements are added inside the ViewStudentApp class. Add necessary private fields:

    private KeywordFilterField _keywordFilterField;  
    private StudentList _studentList;
    private Vector _students;
 

3.8. Add search field and students list:

   MyScreen _mainScreen = new MyScreen(this);

   _students = getFromList();
   _studentList = new StudentList(_students);

    // Add our list to a KeywordFilterField object.
    _keywordFilterField = new KeywordFilterField();                  
    _keywordFilterField.setSourceList(_studentList, _studentList); 

   _mainScreen.setTitle(_keywordFilterField.getKeywordField()); 
    _mainScreen.add(_keywordFilterField);
 

3.8. Add inner class for custom search field:

  final static class CustomKeywordField extends BasicEditField {  
        // Constructor
        CustomKeywordField() {
            // Custom style.
            super(USE_ALL_WIDTH|NON_FOCUSABLE|NO_LEARNING|NO_NEWLINE);
            setLabel("Search: ");
        }

        /**
         * Intercepts ESCAPE key.
         * @see net.rim.device.api.ui.component.TextField#keyChar(char,int,int)
         */
        protected boolean keyChar(char ch, int status, int time) {
            switch(ch) {
            case Characters.ESCAPE:
                // Clear keyword.
                if(super.getTextLength() > 0)
                {
                    setText("");                       
                    return true;
                }
            }               
            return super.keyChar(ch, status, time);
        }                    

        /**
         * Overriding super to add custom painting to our class.
         * @see net.rim.device.api.ui.Field#paint(Graphics)
         */
        protected void paint(Graphics graphics)
        {           
            super.paint(graphics);
            // Draw caret.
            getFocusRect(new XYRect());
            drawFocus(graphics, true);                         
        }
    }
 

3.9. Add the method that creates lists of students:

  private Vector getFromList() {
        Vector students = new Vector();
       
        students.addElement(new Student("Anastasia", "Semionova", "asemionova1@learn.senecac.on.ca"));
        students.addElement(new Student("Minoo", "Ziaei", "minoo.ziaei@senecac.on.ca"));
        students.addElement(new Student("Ladan", "Zadeh", "lzahiroleslamzadeh@learn.senecac.on.ca"));
        students.addElement(new Student("Sergiu", "Ecob", "secob@learn.senecac.on.ca"));
       
        return students;
    }

    /**
     * Adds a new element and updates the student list.
     * @param str The string to be added to the element list.
     */
    void addElementToList(Student student) {      
        _studentList.addElement(student); 
        _keywordFilterField.updateList();
    }
 

3.10. Add the method to access the KeywordFilterField object:

  KeywordFilterField getKeywordFilterField() {
        return _keywordFilterField;
    }
 

3.11. Run the application:

3.12. Type the desired student name in the search field: