menuitem.java

源码为Eclipse开源开发平台桌面开发工具SWT的源代码,

		* Bug in Windows.  When GetMenuItemInfo() is used to get the text,
		* for an item that has a bitmap set using MIIM_BITMAP, the text is
		* not returned.  This means that when SetMenuItemInfo() is used to
		* set the submenu and the current menu state, the text is lost.
		* The fix is to temporarily remove the bitmap and restore it after
		* the text and submenu have been set.
		*/
		if (!OS.IsWinCE && (OS.WIN32_MAJOR << 16 | OS.WIN32_MINOR) >= (4 << 16 | 10)) {
			info.fMask = OS.MIIM_BITMAP;
			OS.GetMenuItemInfo (hMenu, index, true, info);
			hasBitmap = info.hbmpItem != 0;
			if (hasBitmap) {
				info.hbmpItem = 0;
				success = OS.SetMenuItemInfo (hMenu, id, false, info);
			}
		}
		
		int cch = 128;
		int hHeap = OS.GetProcessHeap ();
		int byteCount = cch * TCHAR.sizeof;
		int pszText = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
		info.fMask = OS.MIIM_STATE | OS.MIIM_ID | OS.MIIM_TYPE | OS.MIIM_DATA;
		info.dwTypeData = pszText;
		info.cch = cch;
		success = OS.GetMenuItemInfo (hMenu, index, true, info);
		if (menu != null) {
			menu.cascade = this; 
			info.fMask |= OS.MIIM_SUBMENU;
			info.hSubMenu = menu.handle;
		}
		OS.RemoveMenu (hMenu, index, OS.MF_BYPOSITION);
		if (OS.IsWinCE) {
			/*
			* On WinCE, InsertMenuItem() is not available.  The fix is to
			* use SetMenuItemInfo() but this call does not set the menu item
			* state and submenu.  The fix is to use InsertMenu() to insert
			* the item, SetMenuItemInfo() to set the string and EnableMenuItem()
			* and CheckMenuItem() to set the state.
			*/
			int uIDNewItem = id;
			int uFlags = OS.MF_BYPOSITION;
			if (menu != null) {
				uFlags |= OS.MF_POPUP;
				uIDNewItem = menu.handle;
			}
			TCHAR lpNewItem = new TCHAR (0, " ", true);
			success = OS.InsertMenu (hMenu, index, uFlags, uIDNewItem, lpNewItem);
			if (success) {
				info.fMask = OS.MIIM_DATA | OS.MIIM_TYPE;
				success = OS.SetMenuItemInfo (hMenu, index, true, info);
				if ((info.fState & (OS.MFS_DISABLED | OS.MFS_GRAYED)) != 0) {
					OS.EnableMenuItem (hMenu, index, OS.MF_BYPOSITION | OS.MF_GRAYED);
				}
				if ((info.fState & OS.MFS_CHECKED) != 0) {
					OS.CheckMenuItem (hMenu, index, OS.MF_BYPOSITION | OS.MF_CHECKED);
				}
			}
		} else {
			success = OS.InsertMenuItem (hMenu, index, true, info);
			/*
			* Restore the bitmap that was removed to work around a problem
			* in GetMenuItemInfo() and menu items that have bitmaps set with
			* MIIM_BITMAP.
			*/
			if ((OS.WIN32_MAJOR << 16 | OS.WIN32_MINOR) >= (4 << 16 | 10)) {
				if (hasBitmap) {
					info.fMask = OS.MIIM_BITMAP;
					info.hbmpItem = OS.HBMMENU_CALLBACK;
					success = OS.SetMenuItemInfo (hMenu, id, false, info);
				}
			}
			
		}
		if (pszText != 0) OS.HeapFree (hHeap, 0, pszText);
		if (!success) error (SWT.ERROR_CANNOT_SET_MENU);
	}
	parent.destroyAccelerators ();
}

boolean setRadioSelection (boolean value) {
	if ((style & SWT.RADIO) == 0) return false;
	if (getSelection () != value) {
		setSelection (value);
		postEvent (SWT.Selection);
	}
	return true;
}

/**
 * Sets the selection state of the receiver.
 * <p>
 * When the receiver is of type <code>CHECK</code> or <code>RADIO</code>,
 * it is selected when it is checked.
 *
 * @param selected the new selection state
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public void setSelection (boolean selected) {
	checkWidget ();
	if ((style & (SWT.CHECK | SWT.RADIO)) == 0) return;
	if ((OS.IsPPC || OS.IsSP) && parent.hwndCB != 0) return;
	int hMenu = parent.handle;
	if (OS.IsWinCE) {
		int index = parent.indexOf (this);
		if (index == -1) return;
		int uCheck = OS.MF_BYPOSITION | (selected ? OS.MF_CHECKED : OS.MF_UNCHECKED);
		OS.CheckMenuItem (hMenu, index, uCheck);
	} else {
		MENUITEMINFO info = new MENUITEMINFO ();
		info.cbSize = MENUITEMINFO.sizeof;
		info.fMask = OS.MIIM_STATE;
		boolean success = OS.GetMenuItemInfo (hMenu, id, false, info);
		if (!success) error (SWT.ERROR_CANNOT_SET_SELECTION);
		info.fState &= ~OS.MFS_CHECKED;
		if (selected) info.fState |= OS.MFS_CHECKED;
		success = OS.SetMenuItemInfo (hMenu, id, false, info);
		if (!success) error (SWT.ERROR_CANNOT_SET_SELECTION);
	}
	parent.redraw ();
}
/**
 * Sets the receiver's text. The string may include
 * the mnemonic character and accelerator text.
 * <p>
 * Mnemonics are indicated by an '&amp' that causes the next
 * character to be the mnemonic.  When the user presses a
 * key sequence that matches the mnemonic, a selection
 * event occurs. On most platforms, the mnemonic appears
 * underlined but may be emphasised in a platform specific
 * manner.  The mnemonic indicator character '&amp' can be
 * escaped by doubling it in the string, causing a single
 *'&amp' to be displayed.
 * </p>
 * <p>
 * Accelerator text is indicated by the '\t' character.
 * On platforms that support accelerator text, the text
 * that follows the '\t' character is displayed to the user,
 * typically indicating the key stroke that will cause
 * the item to become selected.  On most platforms, the
 * accelerator text appears right aligned in the menu.
 * Setting the accelerator text does not install the
 * accelerator key sequence. The accelerator key sequence
 * is installed using #setAccelerator.
 * </p>
 * 
 * @param string the new text
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 * 
 * @see #setAccelerator
 */
public void setText (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	if ((style & SWT.SEPARATOR) != 0) return;
	if (text.equals (string)) return;
	super.setText (string);
	int hHeap = OS.GetProcessHeap ();
	int pszText = 0;
	boolean success = false;
	if ((OS.IsPPC || OS.IsSP) && parent.hwndCB != 0) {
		/*
		* Bug in WinCE PPC.  Tool items on the menubar don't resize
		* correctly when the character '&' is used (even when it
		* is a sequence '&&').  The fix is to remove all '&' from
		* the string. 
		*/
		if (string.indexOf ('&') != -1) {
			int length = string.length ();
			char[] text = new char [length];
			string.getChars( 0, length, text, 0);
			int i = 0, j = 0;
			for (i=0; i<length; i++) {
				if (text[i] != '&') text [j++] = text [i];
			}
			if (j < i) string = new String (text, 0, j);
		}
		/* Use the character encoding for the default locale */
		TCHAR buffer = new TCHAR (0, string, true);
		int byteCount = buffer.length () * TCHAR.sizeof;
		pszText = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
		OS.MoveMemory (pszText, buffer, byteCount);	
		int hwndCB = parent.hwndCB;
		TBBUTTONINFO info2 = new TBBUTTONINFO ();
		info2.cbSize = TBBUTTONINFO.sizeof;
		info2.dwMask = OS.TBIF_TEXT;
		info2.pszText = pszText;
		success = OS.SendMessage (hwndCB, OS.TB_SETBUTTONINFO, id, info2) != 0;
	} else {
		MENUITEMINFO info = new MENUITEMINFO ();
		info.cbSize = MENUITEMINFO.sizeof;
		int hMenu = parent.handle;
		
		/*
		* Bug in Windows 2000.  For some reason, when MIIM_TYPE is set
		* on a menu item that also has MIIM_BITMAP, the MIIM_TYPE clears
		* the MIIM_BITMAP style.  The fix is to reset both MIIM_BITMAP.
		* Note, this does not happen on Windows 98.
		*/
		boolean hasBitmap = false;
		if (!OS.IsWinCE && (OS.WIN32_MAJOR << 16 | OS.WIN32_MINOR) >= (4 << 16 | 10)) {
			info.fMask = OS.MIIM_BITMAP;
			OS.GetMenuItemInfo (hMenu, id, false, info);
			hasBitmap = info.hbmpItem != 0;
		}
		
		/* Use the character encoding for the default locale */
		TCHAR buffer = new TCHAR (0, string, true);
		int byteCount = buffer.length () * TCHAR.sizeof;
		pszText = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, byteCount);
		OS.MoveMemory (pszText, buffer, byteCount);	
		info.fMask = OS.MIIM_TYPE;
		info.fType = widgetStyle ();
		info.dwTypeData = pszText;
		success = OS.SetMenuItemInfo (hMenu, id, false, info);

		/*
		* Restore the bitmap that was removed to work around a problem
		* in GetMenuItemInfo() and menu items that have bitmaps set with
		* MIIM_BITMAP.
		*/
		if (!OS.IsWinCE && (OS.WIN32_MAJOR << 16 | OS.WIN32_MINOR) >= (4 << 16 | 10)) {
			if (hasBitmap) {
				info.fMask = OS.MIIM_BITMAP;
				info.hbmpItem = OS.HBMMENU_CALLBACK;
				success = OS.SetMenuItemInfo (hMenu, id, false, info);
			}
		}
	}
	if (pszText != 0) OS.HeapFree (hHeap, 0, pszText);
	if (!success) error (SWT.ERROR_CANNOT_SET_TEXT);
	parent.redraw ();
}

int widgetStyle () {
	int bits = 0;
	Decorations shell = parent.parent;
	if ((shell.style & SWT.MIRRORED) != 0) {
		if ((parent.style & SWT.LEFT_TO_RIGHT) != 0) {
			bits |= OS.MFT_RIGHTJUSTIFY | OS.MFT_RIGHTORDER;
		}
	} else {
		if ((parent.style & SWT.RIGHT_TO_LEFT) != 0) {
			bits |= OS.MFT_RIGHTJUSTIFY | OS.MFT_RIGHTORDER;
		}
	}
	if ((style & SWT.SEPARATOR) != 0) return bits | OS.MFT_SEPARATOR;
	if ((style & SWT.RADIO) != 0) return bits | OS.MFT_RADIOCHECK;
	return bits | OS.MFT_STRING;
}

LRESULT wmCommandChild (int wParam, int lParam) {
	if ((style & SWT.CHECK) != 0) {
		setSelection (!getSelection ());
	} else {
		if ((style & SWT.RADIO) != 0) {
			if ((parent.getStyle () & SWT.NO_RADIO_GROUP) != 0) {
				setSelection (!getSelection ());
			} else {
				selectRadio ();
			}
		}
	}
	Event event = new Event ();
	setInputState (event, SWT.Selection);
	postEvent (SWT.Selection, event);
	return null;
}

LRESULT wmDrawChild (int wParam, int lParam) {
	DRAWITEMSTRUCT struct = new DRAWITEMSTRUCT ();
	OS.MoveMemory (struct, lParam, DRAWITEMSTRUCT.sizeof);
	if (image != null) {
		GCData data = new GCData();
		data.device = display;
		GC gc = GC.win32_new (struct.hDC, data);
		/*
		* Bug in Windows.  When a bitmap is included in the
		* menu bar, the HDC seems to already include the left
		* coordinate.  The fix is to ignore this value when
		* the item is in a menu bar.
		*/
		int x = (parent.style & SWT.BAR) != 0 ? (OS.IsWin95 ? 4 : 2) : struct.left;
		gc.drawImage (image, x, struct.top + 2);
		gc.dispose ();
	}
	return null;
}

LRESULT wmMeasureChild (int wParam, int lParam) {
	MEASUREITEMSTRUCT struct = new MEASUREITEMSTRUCT ();
	OS.MoveMemory (struct, lParam, MEASUREITEMSTRUCT.sizeof);
	int width = 0, height = 0;
	if (image != null) {
		Rectangle rect = image.getBounds ();
		width = rect.width;
		height = rect.height;
	} else {
		/*
		* Bug in Windows.  If a menu contains items that have
		* images and can be checked, Windows does not include
		* the width of the image and the width of the check when
		* computing the width of the menu.  When the longest item
		* does not have an image, the label and the accelerator
		* text can overlap.  The fix is to use SetMenuItemInfo()
		* to indicate that all items have a bitmap and then include
		* the width of the widest bitmap in WM_MEASURECHILD.
		*/
		MENUINFO lpcmi = new MENUINFO ();
		lpcmi.cbSize = MENUINFO.sizeof;
		lpcmi.fMask = OS.MIM_STYLE;
		int hMenu = parent.handle;
		OS.GetMenuInfo (hMenu, lpcmi);
		if ((lpcmi.dwStyle & OS.MNS_CHECKORBMP) == 0) {
			MenuItem [] items = parent.getItems ();
			for (int i=0; i<items.length; i++) {
				MenuItem item = items [i];
				if (item.image != null) {
					Rectangle rect = item.image.getBounds ();
					width = Math.max (width, rect.width); 
				}
			}
		}
	}
	if (width != 0 || height != 0) {
		/*
		* Feature in Windows.  On Windows 98, it is necessary
		* to add 4 pixels to the width of the image or the image
		* and text are too close.  On other Windows platforms,
		* this causes the text of the longest item to touch the
		* accelerator text.  The fix is to add only 2 pixels in
		* this case.
		*/
		struct.itemWidth = width + (OS.IsWin95 ? 4 : 2);
		struct.itemHeight = height + 4;
		OS.MoveMemory (lParam, struct, MEASUREITEMSTRUCT.sizeof);
	}
	return null;
}

}