Customising Blackberry Treefield

Question

I want to customise the (+) sign that appears on the left side of tree view Is it possible I want to place image in that place

i have tried to customise and searched the forums also Blackberry forums where one of them said its not possible but then
i got a link for this As below which says it is possible

http://supportforums.blackberry.com/t5/Java-Development/Custom-TreeField/td-p/354901

where the HardwareDevice class seems to be missing

Can anyone explain this concept using the link or any other answer of their own Please suggest ?

Answer 1

[UPDATED] If you want to CUSTOMISE the (+)-sign and other attributes of each row of a TreeField rather than writing your own tree field then you can try re-writing the drawTreeItem method of TreeFieldCallback like shown below:

import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.TreeField;
import net.rim.device.api.ui.component.TreeFieldCallback;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;

public class TreeDemo extends MainScreen {
    int parent[] = {1,2,3,4,5,6,7,8,9};
    int child[][] = new int [10][10];
    int child_child[][][] = new int [10][10][10];

    int rowHeight = 27;

    CustomTreeFieldCallback treeCallback = new CustomTreeFieldCallback();
    VerticalFieldManager vm = new VerticalFieldManager(Field.FOCUSABLE | VERTICAL_SCROLL | VERTICAL_SCROLLBAR);
    TreeField myTree = new TreeField(treeCallback, Field.FOCUSABLE);

    public TreeDemo() {
        vm.add(new LabelField("Table:"));
        myTree.setRowHeight(rowHeight);
        myTree.setIndentWidth(15);
        myTree.setDefaultExpanded(false);
        for(int i = parent.length-1; i >= 0 ; i--) {
            parent[i] = myTree.addChildNode(0, "Parent_" + (i+1));
            child[i] = new int[4];
            for(int j = child[i].length-1; j >=0 ; j--) {
                child[i][j] = myTree.addChildNode(parent[i], "Child_"+ (i+1) + "_" + (j+1));
                child_child[i][j] = new int[3];
                for(int k = child_child[i][j].length-1; k >= 0 ; k--) {
                    child_child[i][j][k] = myTree.addChildNode(child[i][j], "Child_of_Child_"+ (i+1) + "_" + (j+1)+ "_" + (k+1));
                }
            }
        }
        vm.add(myTree);
        add(vm);
    }

    private class CustomTreeFieldCallback implements TreeFieldCallback {

        public void drawTreeItem(TreeField treeField, Graphics graphics, int node,
                int y, int width, int indent) {
            // TODO Auto-generated method stub
            String string = (String) treeField.getCookie(node);
            int preservedColor = graphics.getColor();

            if(treeField.getCurrentNode() == node) {
                graphics.setColor(0x0CCCC0);
            } else {
                graphics.setColor(0x404040);
            }
            graphics.fillRect(0, y, Display.getWidth(), treeField.getRowHeight());

            Bitmap iconImage;
            int iconImageWidth = 0;
            indent -= 20; // decrease the extra indentation for all nodes.
            if(treeField.getFirstChild(node) != -1){ // if the node is not a leaf node
                if(treeField.getExpanded(node)) {
                    iconImage = Bitmap.getBitmapResource("icon_arrow_down.png");
                    iconImageWidth = iconImage.getWidth();
                } else {
                    iconImage = Bitmap.getBitmapResource("icon_arrow_right.png");
                    iconImageWidth = iconImage.getWidth();
                }
                graphics.drawBitmap(indent, y, indent+iconImageWidth, treeField.getRowHeight(), iconImage, 0, 0);
            }

            if( treeField.getCurrentNode() == node ) {
                graphics.setColor(0x404040);            
            } else {
                graphics.setColor(0x0CCCC0);
            }
            graphics.drawText(string, indent+iconImageWidth, y);

            graphics.setColor(preservedColor);
        }

    }
}

Answer 2

Try this following code foe custom treeField with image

import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FieldChangeListener;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.BitmapField;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.SeparatorField;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;

/**
 * A class extending the MainScreen class, which provides default standard
 * behavior for BlackBerry GUI applications.
 */
public final class MyScreen extends MainScreen implements FieldChangeListener
{
    /**
     * Creates a new MyScreen object
     */
    private VerticalFieldManager main_manager;
    private HorizontalFieldManager parentNodes;
    private LabelField parent_lables[];
    private Bitmap bitmap,upbitmap;
    private BitmapField bitmap_field[];
    private VerticalFieldManager submanager[];
    private int sizeOfParentNodes=3;
    private int sizeOfChildNodes=5;
    private static boolean flag[];

    public MyScreen()
    {        
        // Set the displayed title of the screen       
        bitmap=Bitmap.getBitmapResource("arrow.png");
        upbitmap=Bitmap.getBitmapResource("uparrow.png");
        main_manager=new VerticalFieldManager(Manager.VERTICAL_SCROLL|VERTICAL_SCROLLBAR){
            protected void sublayout(int maxWidth, int maxHeight) {
                super.sublayout(Display.getWidth(), Display.getHeight());
                setExtent(Display.getWidth(), Display.getHeight());
            };
        };
        parent_lables=new LabelField[sizeOfParentNodes];
        flag=new boolean[sizeOfParentNodes];
        submanager=new VerticalFieldManager[sizeOfParentNodes];
        bitmap_field=new BitmapField[sizeOfParentNodes];
        for(int i=0;i<sizeOfParentNodes;i++)
        {
            submanager[i]=new VerticalFieldManager();
            updateGUI(i);
            main_manager.add(submanager[i]);
        }

        add(main_manager);


    }
    public void fieldChanged(Field field, int context) {
        // TODO Auto-generated method stub
        synchronized (UiApplication.getEventLock()) {
            for(int i=0;i<sizeOfParentNodes;i++)
            {   if(field==parent_lables[i])
                {
                    if(flag[i]==true){
                        flag[i]=false;
                        submanager[i].deleteAll();
                        updateGUI(i);
                        parent_lables[i].setFocus();
                    }else{
                        flag[i]=true;
                        bitmap_field[i].setBitmap(upbitmap);
                        for(int j=0;j<sizeOfChildNodes;j++)
                        {
                            submanager[i].add(new LabelField("        Child :"+i+","+j,Field.FOCUSABLE));
                            submanager[i].add(new SeparatorField());
                        }
                        submanager[i].invalidate();
                    }

                }
            }
        }


    }
    public void updateGUI(int index)
    {
        parentNodes=new HorizontalFieldManager(USE_ALL_WIDTH);
        bitmap_field[index]=new BitmapField(bitmap);

        parentNodes.add(bitmap_field[index]);
        parent_lables[index]=new LabelField("Day"+index,Field.FOCUSABLE){
            protected boolean navigationClick(int status, int time) {
                fieldChangeNotify(1);
                return true;
            };
        };
        parentNodes.add(parent_lables[index]);
        parent_lables[index].setChangeListener(this);
        submanager[index].add(parentNodes);
    }
}

you can get output as