Java Development

[YoungSkywalker]

Hi,

 i've read this tutorial

http://www.blackberry.com/knowledgecenterpublic/livelink.exe/fetch/2000/348583/800332/800505/800345/...

to create a list of elements on mail screen.

Now i would like, when i select one item of the list, open  a new screen for visualize another information.

How can i make it?

In the development guide there is only written to use  navigationclick but i don't understand where to use it

Thanks

[simon_hain]

you can use getSelectedIndex to get the index, use it to retrieve the object from the vector/array used with the listfield.

you can overwrite navigationclick and makemenu to trigger your method.

[Blanc]

protected boolean navigationClick(int status, int time)
{
    Field field = this.getFieldWithFocus();
    
    if(field instanceof ListField)
    {
      // listValues is String[] where you store your list elements.
      // listField is the ListField instance you are using 
       String selectedText = listValues[listField.getSelectedIndex()];
       return true;
     }

    return super.navigationClick(status, time);
}

you can place this code in your custom list field or in the manager class wheere you are adding your list field

[joelajean]

I've added the following method to the TableFieldList which allows me to retreive the selected row...

  public Manager getSelectedRow()
  {
    int selectedIndex = this.getSelectedIndex();
    return _rows[selectedIndex];
  }

So, when I instantiate the TableFieldList, I override the navigationClick event with the following code...

public boolean navigationClick(int status, int time)
{
  Manager m = this.getSelectedRow();
  LabelField selectedIncidentNumber = (LabelField)m.getField(0);
  Dialog.alert(selectedIncidentNumber.getText()) ;
  return true;
}

 
It works great !

[YoungSkywalker]

Sorry but i'm just starting to write for bb.

I've put the code

_listElements = new Vector();
_listField = new ListField();

   protected boolean navigationClick(int status, int time)
   {
       Field field = this.getFieldWithFocus();
       
       if(field instanceof ListField)
       {
         // listValues is String[] where you store your list elements.
         // listField is the ListField instance you are using 
    String selectedText =_listElements[_listField.getSelectedIndex()];
          return true;
        }

       return super.navigationClick(status, time);
   }

in my demoScreen class but on this line:

 String selectedText =_listElements[_listField.getSelectedIndex()];

 i've the error:

The type of the expression must be an array type but it resolved to Vector.

Where i'm wrong?

[simon_hain]

did you implement ListFieldCallback? you have to register it with the listfield, it manages the objects.

there are numerous samples floating around that can sure help you (forums and kb)

[YoungSkywalker]

Yes, this is my entire code:

public class demo extends UiApplication {
	public static void main(String[] args) {
	
		demo App = new demo();
		App.enterEventDispatcher();
	}
	
	public demo() {
	pushScreen(new demoScreen());
	}


	
   private class demoScreen extends MainScreen {
	 ListField _listField;
	 Vector _listElements;
	 ListCallback _callback;
	 
	public demoScreen() {
	super();	

	
	LabelField title = new LabelField("Demo",LabelField.FIELD_HCENTER | LabelField.USE_ALL_WIDTH);
			setTitle(title);
			
	_listElements = new Vector();
	_listField = new ListField();
	_callback = new ListCallback();
	_listField.setCallback(_callback);
	add(_listField);
	initializeList();
	
	}
	
   private void initializeList()
   {
   String itemOne = "Element 1";
   String itemTwo = "Element 2";
   _listElements.addElement(itemOne);
   _listElements.addElement(itemTwo);  
   reloadList();
   
   }
   private void reloadList()
   {
   _listField.setSize(_listElements.size());
   }

   private class ListCallback implements ListFieldCallback
   {
   public void drawListRow(ListField list, Graphics g, int index, int y, int w)
   {
   String text = (String)_listElements.elementAt(index);
   g.drawText(text, 0, y, 0, w);
   }
   public Object get(ListField list, int index)
   {
   return _listElements.elementAt(index);
   }
   public int indexOfList(ListField list, String prefix, int string)
   {
   return _listElements.indexOf(prefix, string);
   }
   public int getPreferredWidth(ListField list)
   {
	   return Display.getWidth();
   }
   }
   protected boolean navigationClick(int status, int time)
   {
       Field field = this.getFieldWithFocus();
       
       if(field instanceof ListField)
       {
         // listValues is String[] where you store your list elements.
         // listField is the ListField instance you are using 
          String selectedText = _listElements[_listField.getSelectedIndex()];
          return true;
        }

       return super.navigationClick(status, time);
   }

  }
}

[simon_hain]

retrieve elements from a vector using elementAt(index i), not [index]

[YoungSkywalker]

If i understand now i must write the following code:

String selectedText = (String)_listElements.elementAt(_listField.getSelectedIndex());

now, how can i create a new screen  from this?

Sorry but i can't find a post that talking about this stuff!

[YoungSkywalker · Accepted solution]

I tried this solution and it works:

   protected boolean navigationClick(int status, int time)
   {
       Field field = this.getFieldWithFocus();
       
       if(field instanceof ListField)
       {
        
    	   int selected = _listField.getSelectedIndex();
    	   switch (selected) {
		case 0:
			pushScreen(new Screen1());
			break;
		case 1:
			pushScreen(new Screen2());
			break;
		case 2:
			pushScreen(new Screen3());
			break;
		case 3:
			pushScreen(new Screen4());
			break;
		case 4:
			pushScreen(new Screen5());
			break;
		default:
			break;
		}
          return true;
        }

       return super.navigationClick(status, time);
   }

  }