How to Re-Arrange ListField in Blackberry

Question

How to re-arrange the items of a ListField? I want to select the item on click on Blackberry (Storm and Torch) Touch Phones. After select I want to (Move and Drag) Scroll item V

Answer 1

I was also working on custom ListField recently and I hope the following code is going to help you.

In the example below, I've customized a VerticalFieldManager to create a ListField for both touch supported and non-touch BB devices.

Position of the ListField items can be changed-

-- by just DRAG an item and DROP on another item of the ListField (for touch supported devices)

or

-- by pressing SPACE-BAR on the first item and then on the second item (for both touch and non-touch devices).

Sample screenshot for (touch) Drag & Drop below:

Sample screenshot for (non-touch) SPACE-BAR pressing below:

In this sample I've implemented vertical scrolling in the ListField and have also created a traditional scrollbar.

Here is the code of my sample screen for ListField customization:

import net.rim.device.api.system.Characters;
import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.TouchEvent;
import net.rim.device.api.ui.XYEdges;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.component.ListField;
import net.rim.device.api.ui.component.ListFieldCallback;
import net.rim.device.api.ui.component.ObjectListField;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.ui.decor.BackgroundFactory;
import net.rim.device.api.ui.decor.Border;
import net.rim.device.api.ui.decor.BorderFactory;

public class ListTestScreen extends MainScreen {
    private VerticalFieldManager mainManager = new VerticalFieldManager( USE_ALL_WIDTH |FIELD_HCENTER);
    public ListTestScreen() {
        mainManager.setBackground(BackgroundFactory.createSolidBackground(0x808080));
        LabelField lblTitle = new LabelField("FIFA World Cup Country List:",FIELD_HCENTER);
        lblTitle.setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
        XYEdges edges = new XYEdges(2, 2, 2, 2);
        lblTitle.setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
        mainManager.add(lblTitle);
        mainManager.add(new MyList());
        LabelField lblOther = new LabelField("Some Other Field",FIELD_HCENTER);
        lblOther.setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
        lblOther.setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
        mainManager.add(lblOther);
        add(mainManager);
    }
}

class MyList extends VerticalFieldManager implements ListFieldCallback {
    private int  mouseDownY, mouseUpY;
    private static int listRowHeight = 30;
    private int mouseDownRowIndex, mouseUpRowIndex;
    int firstSelectedRow=-1, secondSelectedRow=-1;
    private int touchX;
    private int touchY;
    private int listVisibleHeight = 250;
    private int listVisibleWidth = 200;

    private boolean showShadow = false;

    private ObjectListField list;
    private Object[] listData = new Object[] { "South Africa", "Argentina", "Germany",
            "Australia","Nigeria","Greece","England","Italy","Brazil","Spain","Paraguay","France","Uruguay",
            "Mexico","Cameroon","Denmark","Portugal","Netherlands","Ghana","Chile",
            "South Korea","USA","Algeria","Slovenia","Japan","Switzerland","Honduras"};

    public MyList() {
        super(VERTICAL_SCROLL|FIELD_HCENTER);
        init();
        setBackground(BackgroundFactory.createSolidBackground(0xF0F0F0));
        XYEdges edges = new XYEdges(6, 6, 6, 6);
        setBorder(BorderFactory.createRoundedBorder(edges, 0xB0B0B0, Border.STYLE_FILLED));
    }

    private void init() {
        list = new ObjectListField(FOCUSABLE|Field.FIELD_HCENTER);
        list.setRowHeight(listRowHeight);
        list.setCallback(this);
        list.set(listData);
        add(list);
    }

    private void changeRowPosition(int fromRow, int toRow) {
        Object temp = listData[fromRow];
        int increment = (fromRow 0) {
                    index--;
                }
            } else if(touchY> (getPreferredHeight()-5)) {
                if(index