blackberry how to create Tabbar?

Hi all how to create Tab bar in blackberry开发者_Go百科 ?

Take a look at this entry:

How To - Create tabbed view screens

The example included:

package com.rim.samples.tabcontrol;

import net.rim.device.api.ui.Field;
import net.rim.device.api.ui.FocusChangeListener;
import net.rim.device.api.ui.UiApplication;
import net.rim.device.api.ui.component.BasicEditField;
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;

public class TabControl extends UiApplication {

    public TabControl() {
        TabControlScreen screen = new TabControlScreen();
        pushScreen(screen);
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        TabControl app = new TabControl();
        app.enterEventDispatcher();
    }

    private class TabControlScreen extends MainScreen implements FocusChangeListener {

        private LabelField tab1;

        private LabelField tab2;

        private LabelField tab3;

        private LabelField spacer1;

        private LabelField spacer2;

        private VerticalFieldManager tabArea;

        private LabelField tab1Heading;

        private BasicEditField tab1Field1;

        private BasicEditField tab1Field2;

        private LabelField tab2Heading;

        private BasicEditField tab2Field1;

        private BasicEditField tab2Field2;

        private LabelField tab3Heading;

        private BasicEditField tab3Field1;

        private BasicEditField tab3Field2;

        private VerticalFieldManager tab1Manager;
        private VerticalFieldManager tab2Manager;
        private VerticalFieldManager tab3Manager;


        public TabControlScreen() {
            HorizontalFieldManager hManager = new HorizontalFieldManager();
            tab1 = new LabelField("Page 1", LabelField.FOCUSABLE | LabelField.HIGHLIGHT_SELECT);
            tab2 = new LabelField("Page 2", LabelField.FOCUSABLE | LabelField.HIGHLIGHT_SELECT);
            tab3 = new LabelField("Page 3", LabelField.FOCUSABLE | LabelField.HIGHLIGHT_SELECT);
            spacer1 = new LabelField(" | ", LabelField.NON_FOCUSABLE);
            spacer2 = new LabelField(" | ", LabelField.NON_FOCUSABLE);

            tab1.setFocusListener(this);
            tab2.setFocusListener(this);
            tab3.setFocusListener(this);
            hManager.add(tab1);
            hManager.add(spacer1);
            hManager.add(tab2);
            hManager.add(spacer2);
            hManager.add(tab3);

            add(hManager);
            add(new SeparatorField());

            tab1Manager = new VerticalFieldManager();
            tab2Manager = new VerticalFieldManager();
            tab3Manager = new VerticalFieldManager();

            tabArea = displayTab1();
            add(tabArea);

        }

        public void focusChanged(Field field, int eventType) {
            if (tabArea != null) {
                if (eventType == FOCUS_GAINED) {
                    if (field == tab1) {
                        System.out.println("Switch to Tab 1");
                        delete(tabArea);
                        tabArea = displayTab1();
                        add(tabArea);
                    } else if (field == tab2) {
                        System.out.println("Switch to Tab 2");
                        System.out.println("Switch to Tab 1");
                        delete(tabArea);
                        tabArea = displayTab2();
                        add(tabArea);
                    } else if (field == tab3) {
                        System.out.println("Switch to Tab 3");
                        System.out.println("Switch to Tab 1");
                        delete(tabArea);
                        tabArea = displayTab3();
                        add(tabArea);
                    }
                }
            }

        }

        public VerticalFieldManager displayTab1() {
            if (tab1Heading == null) {
                tab1Heading = new LabelField("Registration");
                tab1Manager.add(tab1Heading);
            }
            if (tab1Field1 == null) {
                tab1Field1 = new BasicEditField("Username: ", "");
                tab1Manager.add(tab1Field1);
            }
            if (tab1Field2 == null) {
                tab1Field2 = new BasicEditField("Password: ", "");
                tab1Manager.add(tab1Field2);
            }
            return tab1Manager;
        }

        public VerticalFieldManager displayTab2() {
            if (tab2Heading == null) {
                tab2Heading = new LabelField("Password Recovery");
                tab2Manager.add(tab2Heading);
            }
            if (tab2Field1 == null) {
                tab2Field1 = new BasicEditField("Security Question: ", "Mother's Maiden Name?");
                tab2Manager.add(tab2Field1);
            }
            if (tab2Field2 == null) {
                tab2Field2 = new BasicEditField("Password: ", "");
                tab2Manager.add(tab2Field2);
            }
            return tab2Manager;
        }

        public VerticalFieldManager displayTab3() {
            if (tab3Heading == null) {
                tab3Heading = new LabelField("Interests");
                tab3Manager.add(tab3Heading);
            }
            if (tab3Field1 == null) {
                tab3Field1 = new BasicEditField("Hobbies: ", "");
                tab3Manager.add(tab3Field1);
            }
            if (tab3Field2 == null) {
                tab3Field2 = new BasicEditField("Memberships: ", "");
                tab3Manager.add(tab3Field2);
            }
            return tab3Manager;
        }

    }

}

for the custom tabbar:

public class BottomPanel extends VerticalFieldManager implements
    FieldChangeListener {
Bitmap news_bit = Bitmap.getBitmapResource("news.png");// these images are
                                                        // cutting according
                                                        // to device
                                                        // requirement;
Bitmap news_bit_hover = Bitmap.getBitmapResource("news_h.png");
Bitmap settings_bit = Bitmap.getBitmapResource("settings.png");
Bitmap settings_bit_hover = Bitmap.getBitmapResource("settings_h.png");
Bitmap about_bit = Bitmap.getBitmapResource("about.png");
Bitmap about_bit_hover = Bitmap.getBitmapResource("about_h.png");
PictureBackgroundButtonField news_pic, settings_pic, about_pic;
HorizontalFieldManager hr;
int current_index = 0;

public BottomPanel(int current_index) {
    super(FOCUSABLE);
    this.current_index = current_index;
    VerticalFieldManager ver = new VerticalFieldManager(USE_ALL_WIDTH
            | USE_ALL_HEIGHT) {
        protected void sublayout(int width, int height) {
            super.sublayout(width, news_bit.getHeight());
            setExtent(width, news_bit.getHeight());
        }
    };
    hr = new HorizontalFieldManager(FIELD_HCENTER);
    if (current_index == 1) {
        news_pic = new PictureBackgroundButtonField(news_bit.getWidth(),
                news_bit.getHeight(), Field.NON_FOCUSABLE
                        | Field.FIELD_VCENTER, news_bit_hover,
                news_bit_hover);
    } else {
        news_pic = new PictureBackgroundButtonField(news_bit.getWidth(),
                news_bit.getHeight(),
                Field.FOCUSABLE | Field.FIELD_VCENTER, news_bit,
                news_bit_hover);
    }
    news_pic.setChangeListener(this);
    hr.add(news_pic);

    if (current_index == 2) {
        settings_pic = new PictureBackgroundButtonField(
                settings_bit.getWidth(), settings_bit.getHeight(),
                Field.NON_FOCUSABLE | Field.FIELD_VCENTER,
                settings_bit_hover, settings_bit_hover);
    } else {
        settings_pic = new PictureBackgroundButtonField(
                settings_bit.getWidth(), settings_bit.getHeight(),
                Field.FOCUSABLE | Field.FIELD_VCENTER, settings_bit,
                settings_bit_hover);
    }
    settings_pic.setChangeListener(this);
    hr.add(settings_pic);

    if (current_index == 3) {
        about_pic = new PictureBackgroundButtonField(about_bit.getWidth(),
                about_bit.getHeight(), Field.NON_FOCUSABLE
                        | Field.FIELD_VCENTER, about_bit_hover,
                about_bit_hover);
    } else {
        about_pic = new PictureBackgroundButtonField(about_bit.getWidth(),
                about_bit.getHeight(), Field.FOCUSABLE
                        | Field.FIELD_VCENTER, about_bit, about_bit_hover);
    }
    about_pic.setChangeListener(this);
    hr.add(about_pic);

    ver.add(hr);
    add(ver);
    ver.setBackground(BackgroundFactory.createSolidBackground(Color.BLACK));
}

public void fieldChanged(Field field, int context) {
    if (field == news_pic) {
        LoadingScreenDemo loadingScreen = new LoadingScreenDemo(1);
        UiApplication.getUiApplication().popScreen(
                UiApplication.getUiApplication().getActiveScreen());
        UiApplication.getUiApplication().pushScreen(loadingScreen);
        //loadingScreen.createGUI();

    } else if (field == settings_pic) {

        SecondTab loadingScreen = new SecondTab(2);
        UiApplication.getUiApplication().popScreen(
                UiApplication.getUiApplication().getActiveScreen());
        UiApplication.getUiApplication().pushScreen(loadingScreen);

    } else if (field == about_pic) {
        ThirdTab loadingScreen = new ThirdTab(3);
        UiApplication.getUiApplication().popScreen(
                UiApplication.getUiApplication().getActiveScreen());
        UiApplication.getUiApplication().pushScreen(loadingScreen);
    }
}

}

public class PictureBackgroundButtonField extends Field {
private String _label;
private int _labelHeight;
private int _labelWidth;
private Font _font;

private Bitmap _currentPicture;
private Bitmap _onPicture;
private Bitmap _offPicture;

public PictureBackgroundButtonField(int width, int height, long style,
        Bitmap picture, Bitmap selectedPic) {
    super(style);

    _font = getFont();
    _label = "";
    _labelHeight = height;
    _labelWidth = width;
    _currentPicture = picture;
    _onPicture = selectedPic;
    _offPicture = picture;
}

public int getPreferredHeight() {
    return _labelHeight + 10;
}

public int getPreferredWidth() {
    return _labelWidth + 20;
}

protected void onFocus(int direction) {
    _currentPicture = _onPicture;
    invalidate();
}

protected void onUnfocus() {
    _currentPicture = _offPicture;
    invalidate();
}

protected void drawFocus(Graphics graphics, boolean on) {
    // Do nothing
}

protected void layout(int width, int height) {
    setExtent(getPreferredWidth(), getPreferredHeight());
}

protected void paint(Graphics graphics) {
    graphics.drawBitmap(3, 6, getPreferredWidth(), getPreferredHeight(),
            _currentPicture, 0, 0);
    graphics.setFont(_font);
    graphics.drawText(
            _label,
            4,
            2,
            (int) (getStyle() & DrawStyle.ELLIPSIS | DrawStyle.HALIGN_MASK),
            getWidth() - 6);
}

protected boolean navigationClick(int status, int time) {
    fieldChangeNotify(1);
    return true;
}
}

set as a bottom in class:

BottomPanel bottomPanel=new BottomPanel(0);

setStatus(bottomPanel);