VerticalFieldManager不滚动

我正在开发一个应用程序，其中我在 LableField 中设置了大量文本，我希望它可以在模拟器8900中进行滚动 . 所以为此我采取了 VerticalFieldManager 并将 LableField 放入其中 . 我使用 VERTICAL_SCROLL 进行了 VerticalFieldManager 可滚动，并尝试使用 Manager.VERTICAL_SCROLL . 但它仍然无法正常工作 .

My code

import net.rim.device.api.system.Bitmap;
import net.rim.device.api.system.Display;
import net.rim.device.api.ui.Color;
import net.rim.device.api.ui.Font;
import net.rim.device.api.ui.FontFamily;
import net.rim.device.api.ui.Graphics;
import net.rim.device.api.ui.Manager;
import net.rim.device.api.ui.component.BitmapField;
import net.rim.device.api.ui.component.LabelField;
import net.rim.device.api.ui.container.HorizontalFieldManager;
import net.rim.device.api.ui.container.MainScreen;
import net.rim.device.api.ui.container.VerticalFieldManager;
import net.rim.device.api.ui.decor.BackgroundFactory;

public class AboutM1 extends MainScreen {

    public AboutM1() {

        ((VerticalFieldManager) getMainManager())
                .setBackground(BackgroundFactory
                        .createSolidBackground(0xEDEDED));

        VerticalFieldManager TOPVFM = new VerticalFieldManager(USE_ALL_WIDTH);
        HorizontalFieldManager TOPHFM = new HorizontalFieldManager(
                FIELD_HCENTER | FIELD_VCENTER);
        // LabelField toplable = new LabelField("Welcome to");

        LabelField toplable = new LabelField("\n Welcome to", FIELD_BOTTOM) {
            public void paint(Graphics g) {
                g.setBackgroundColor(0xECECEC);
                g.fillRect(0, 0, getWidth(), getHeight());
                g.setColor(Color.RED);

                g.clear();
                super.paint(g);
            }
        };

        FontFamily fontFamily[] = FontFamily.getFontFamilies();
        Font font = fontFamily[1].getFont(FontFamily.CBTF_FONT, 20);
        font = fontFamily[1].getFont(Font.BOLD, 25);
        toplable.setFont(font);

        Bitmap bmp = Bitmap.getBitmapResource("logo36X36.png");
        BitmapField imgField = new BitmapField(bmp, FIELD_BOTTOM);

        TOPHFM.add(toplable);
        TOPHFM.add(imgField);

        TOPVFM.add(TOPHFM);

        int width = Display.getWidth();

        add(TOPVFM);
        LabelField Greenline = new LabelField(
                "_______________________________________") {
            protected void paint(Graphics g) {
                int oldColor = g.getColor();
                g.setColor(Color.GREEN);
                // g.fillRoundRect(0, 0, 50, 5, 7, 7);
                g.setColor(oldColor);
                super.paint(g);
            }

        };

        add(Greenline);

        VerticalFieldManager DescriptionVFM = new VerticalFieldManager(
                VERTICAL_SCROLL);
        LabelField Description = new LabelField(
                "\n asdasdawqwere we r we r we rw er w er wer, groceries, sadfertewrt er te rt ert er t er t er t er t . asdasdasdasdas asd asd werwerewrt er t erter t ert.",
                FIELD_HCENTER);
        LabelField Description2 = new LabelField(
                "\n\n\n About Us \n For customer care \n\n");
        /*
         * add(Description); add(Description2);
         */

        DescriptionVFM.add(Description);
        DescriptionVFM.add(Description2);

        VerticalFieldManager BottomVFM = new VerticalFieldManager(USE_ALL_WIDTH);
        HorizontalFieldManager BottomHFM = new HorizontalFieldManager(
                FIELD_VCENTER);
        LabelField callus = new LabelField("Call: ", FIELD_VCENTER);
        LabelField Number = new LabelField("+91-79-30487400", FIELD_VCENTER) {
            protected void paint(Graphics g) {
                g.setColor(0x324F85);

                // g.fillRoundRect(0, 0, 50, 5, 7, 7);
                super.paint(g);
            }

        };
        font = fontFamily[1].getFont(Font.BOLD, 18);
        Number.setFont(font);

        BottomHFM.add(callus);
        BottomHFM.add(Number);
        BottomVFM.add(BottomHFM);
        // add(BottomVFM);
        DescriptionVFM.add(BottomVFM);
        add(DescriptionVFM);

    }
}