BlackBerry - How to create sub menu? - user-interface

Question

i want to create sub menu for a BB application
when i click on menu item it shows
Option 1
Option 2
Option 3
When i click on option 3 it should display
1
2
3
as sub menu items..
using j2me + eclipse

Answer 1

Always wanted to do this )
alt text http://img380.imageshack.us/img380/3874/menugy.jpg
class Scr extends MainScreen {
SubMenu menu = new SubMenu();
public Scr() {
for (int i = 0; i < 3; i++) {
SubMenu sMenu = new SubMenu();
menu.add(new SubMenuItem(i + " item", sMenu));
for (int k = 0; k < 3; k++) {
SubMenu sSMenu = new SubMenu();
sMenu.add(new SubMenuItem(i + "-" + k + " item", sSMenu));
for (int l = 0; l < 3; l++) {
sSMenu
.add(new SubMenuItem(i + "-" + k + "-" + l
+ " item"));
}
}
}
add(new LabelField("testing menu", FOCUSABLE) {
protected void makeContextMenu(ContextMenu contextMenu) {
menu.mRectangle.x = this.getContentRect().X2();
menu.mRectangle.y = this.getContentRect().Y2();
Ui.getUiEngine().pushScreen(menu);
EventInjector.invokeEvent(new KeyEvent(KeyEvent.KEY_DOWN,
Characters.ESCAPE, 0));
}
});
}
}
class SubMenu extends PopupScreen implements ListFieldCallback {
private static final int MAX_WIDTH = Font.getDefault().getAdvance(
"max menu item text");
XYRect mRectangle = new XYRect();
Vector mSubMenuItems = new Vector();
ListField mListField;
public SubMenu() {
super(new SubMenuItemManager(), DEFAULT_CLOSE);
int rowHeight = getFont().getHeight() + 2;
mListField = new ListField() {
protected boolean navigationClick(int status, int time) {
runMenuItem(getSelectedIndex());
return super.navigationClick(status, time);
}
};
mListField.setRowHeight(rowHeight);
add(mListField);
mListField.setCallback(this);
updateMenuItems();
}
public void add(SubMenuItem subMenuItem) {
mSubMenuItems.addElement(subMenuItem);
subMenuItem.mMenu = this;
updateMenuItems();
}
private void updateMenuItems() {
int rowCounts = mSubMenuItems.size();
mRectangle.width = getMaxObjectToStringWidth(mSubMenuItems);
mRectangle.height = mListField.getRowHeight() * rowCounts;
mListField.setSize(rowCounts);
}
private void runMenuItem(int index) {
SubMenuItem item = (SubMenuItem) get(mListField, index);
if (null != item.mSubMenu) {
item.mSubMenu.setSubMenuPosition(getSubMenuRect(index));
Ui.getUiEngine().pushScreen(item.mSubMenu);
} else {
item.run();
}
}
private XYRect getSubMenuRect(int index) {
SubMenuItem item = (SubMenuItem) get(mListField, index);
XYRect result = item.mSubMenu.mRectangle;
result.x = mRectangle.x + mRectangle.width;
result.y = mRectangle.y + mListField.getRowHeight() * index;
int testWidth = Display.getWidth() - (mRectangle.width + mRectangle.x);
if (testWidth < result.width) {
result.width = testWidth;
}
int testHeight = Display.getHeight()
- (mRectangle.height + mRectangle.y);
if (testHeight < result.height)
result.height = testHeight;
return result;
}
public void setSubMenuPosition(XYRect rect) {
mRectangle = rect;
}
protected void sublayout(int width, int height) {
super.sublayout(mRectangle.width, mRectangle.height);
setPosition(mRectangle.x, mRectangle.y);
setExtent(mRectangle.width, mRectangle.height);
}
private int getMaxObjectToStringWidth(Vector objects) {
int result = 0;
for (int i = 0; i < objects.size(); i++) {
int width = getFont().getAdvance(objects.elementAt(i).toString());
if (width > result) {
if (width > MAX_WIDTH) {
result = MAX_WIDTH;
break;
} else {
result = width;
}
}
}
return result;
}
public void drawListRow(ListField field, Graphics g, int i, int y, int w) {
// Draw the text.
String text = get(field, i).toString();
g.setColor(Color.WHITE);
g.drawText(text, 0, y, DrawStyle.ELLIPSIS, w);
}
public Object get(ListField listField, int index) {
return mSubMenuItems.elementAt(index);
}
public int getPreferredWidth(ListField listField) {
return mRectangle.width;
}
public int indexOfList(ListField listField, String prefix, int start) {
return 0;
}
}
class SubMenuItemManager extends VerticalFieldManager {
public SubMenuItemManager() {
super(USE_ALL_HEIGHT | USE_ALL_WIDTH);
}
public int getPreferredWidth() {
return ((SubMenu) getScreen()).mRectangle.width;
}
public int getPreferredHeight() {
return ((SubMenu) getScreen()).mRectangle.height;
}
protected void sublayout(int maxWidth, int maxHeight) {
maxWidth = getPreferredWidth();
maxHeight = getPreferredHeight();
super.sublayout(maxWidth, maxHeight);
setExtent(maxWidth, maxHeight);
}
}
class SubMenuItem implements Runnable {
String mName;
SubMenu mMenu;
SubMenu mSubMenu;
public SubMenuItem(String name) {
this(name, null);
}
public SubMenuItem(String name, SubMenu subMenu) {
mName = name;
mSubMenu = subMenu;
}
public String toString() {
return mName;
}
public void run() {
}
}

Answer 2

Submenus are not part of the standard BlackBerry API. If you want to do this, you'll have to make your own custom menu+submenu control.