Dear All, I have a problem when creating a UI on Blackberry.

First, i try to create a ChatLayoutManager class extended from Manager class. My layout has three component: topfield, mainfield and bottom field.

public class ChatLayoutManager extends Manager {  
   private Field bottomField;  
   private Field mainField;  
   private Field titleField;  

   public ChatLayoutManager(long style) {  
       super(style);  
   }  

   protected void sublayout(int width, int height) {  
       setExtent(width, height);  

       int y = 0;  
       if (bottomField != null) {  
           layoutChild(bottomField, width, height);  
           // This goes at the bottom of the screen  
           setPositionChild(bottomField, 0, height-bottomField.getHeight());  
           height -= bottomField.getHeight();  
       }  

       if (titleField != null) {  
           layoutChild(titleField, width, height);  
           // This goes at the top of the screen  
           setPositionChild(titleField, 0, 0);  
           height -= titleField.getHeight();  
           y += titleField.getHeight();  
       }  

       if (mainField != null) {  

           layoutChild(mainField, width, height);  
           // This goes just below the title field (if any)  
           setPositionChild(mainField, 0, y);  
       }  

   }  

   public void setMainField(Field f) {  
       mainField = f;  
       add(f);  
   }  

   public void setBottomField(Field f) {  
       bottomField = f;  
       add(f);  
   }  

   public void setTitleField(Field f) {  
       titleField = f;  
       add(f);  
   }  

Then i create another field (ChatField) extended from manager to add to mainfield in the ChatLayoutManager class which i have created above.

public class ChatField extends Manager{

private Field _contentField[];

protected ChatField(){
    super(Manager.HORIZONTAL_SCROLL | Manager.VERTICAL_SCROLL);
}
// TODO Auto-generated constructor stub}

protected synchronized void sublayout(int width, int height) {
    // TODO Auto-generated method stub
    setExtent(width, height);
    int x = 0;
    int y = 0;

    if(_contentField.length > 0){
        for(int i = 0 ;i<_contentField.length; i++){
            //if(getManager() == this){
                this.layoutChild(_contentField[i],
                            _contentField[i].getWidth(), 
                            _contentField[i].getHeight());
                this.setPositionChild(_contentField[i], x, y);
                if(_contentField[i++]!= null){
                    if ((_contentField[i].getWidth() + _contentField[i].getWidth())
                            >= width){
                        x = 0;
                        y += _contentField[i].getHeight();
                    }
                    else{
                        x += _contentField[i].getWidth();

                    }
                }
            //}
        }

    }

}

public void setContentField(Field field[]){
    _contentField = field;
}

}

And now, when i create some fields(such as TextField, BitmapField ...) added to ChatField, the program has an error "Field is not a child of this manager". The reason is when the framework invokes the sublayout function of the ChatField class , when sublayout starts calling layoutChild function the manager of field is not ChatField but ChatlayoutManager.

I've experience hard time trying to resolve this problem, still I have no solution. Anybody can give me some suggestions? I really appreciate.