Java Development

[delidumrul]

Hi Everyone,

I have a legacy code which uses VerticalFieldManager inside an AbsoluteFieldManager. And i need to scroll down in the VerticalFieldManager. If i by pass the AbsoluteFieldManager and add the VerticalFieldManager to the screen directly scrolling works fine but in AbsoluteFieldManager it does not.

Could you please advice on how to solve this problem ?

Sample code is below, 

Regards,

package mypackage;

import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.container.MainScreen;

/**
 * A class extending the MainScreen class, which provides default standard
 * behavior for BlackBerry GUI applications.
 */
public final class MyScreen extends MainScreen
{
    /**
     * Creates a new MyScreen object
     */
    public MyScreen()
    {        
        super(Manager.NO_VERTICAL_SCROLL);
    	// Set the displayed title of the screen       
        setTitle("MyTitle");
    }
}

package mypackage;

import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.NullField;
import net.rim.device.api.ui.component.SeparatorField;
import net.rim.device.api.ui.container.AbsoluteFieldManager;
import net.rim.device.api.ui.container.VerticalFieldManager;

/**
 * This class extends the UiApplication class, providing a
 * graphical user interface.
 */
public class MyApp extends UiApplication
{
    /**
     * Entry point for application
     * @param args Command line arguments (not used)
     */ 
    public static void main(String[] args)
    {
        MyApp theApp = new MyApp();       
        theApp.enterEventDispatcher();
    }
    

    /**
     * Creates a new MyApp object
     */
    public MyApp()
    {        
      MyScreen myScreen = new MyScreen();

      //Create a scrollable VerticalFieldManager.
      VerticalFieldManager vfm = new VerticalFieldManager(VerticalFieldManager.VERTICAL_SCROLL);

      //Add a focusable NullField to the top of the screen to allow the user to scroll to the top.
      vfm.add(new NullField(NullField.FOCUSABLE));

      //Add 10 fields. 
      for (int count = 30; count >= 0; --count)

      {
      vfm.add(new LabelField("Field number " + count, LabelField.NON_FOCUSABLE));
      vfm.add(new SeparatorField());

      }

      //Add a focusable NullField to the bottom of the screen to allow the user to scroll to the bottom.
      vfm.add(new NullField(NullField.FOCUSABLE));

      
      AbsoluteFieldManager manager = new AbsoluteFieldManager();
      manager.add(vfm);
      
      myScreen.add(manager);
      pushScreen(myScreen);
    }    
}

[simon_hain]

why do you use an absolutefieldmanager if you don't use its functionality?
to use it properly you should most likely use http://www.blackberry.com/developers/docs/7.1.0api/net/rim/device/api/ui/container/AbsoluteFieldMana...

addig fields in loops is very costly, better use addAll.
or use a listfield instead of 30 labels.

[delidumrul]

Hi,

thanks for the reply but above code is just a sample code to show to problem i face.

Normally i am adding the vertical manager to the absolute manager with x, y coordinates. And i also do some stuff on the absolute manager like showing a header and bg image...

[arkadyz]

Unfortunately, AbsoluteFieldManager seems to have been added to BlackBerry as an afterthought, and it has some serious problems with layout. I'm not sure it properly sets its virtual extent.

I suggest looking at this old post to get some understanding of how layout should be done - you might want to import some of that into your code, overriding AFM's sublayout, calling super.sublayout there and then going through the fields and finding out your actual dimensions:

AbsoluteFieldManager on OS prior to 5.0

There was at least one poster here who made use of that:

Horizontal Scrolling in AbsoluteFieldManager

Besides, there were reports about some genuine bugs with AFM:

Bug with AbsoluteFieldManager

Good luck weeding out this problem!