A popup menu widget is a selection menu. It can be either a pull-down menu in a menu bar or a standalone context (popup) menu. Pull-down menus are shown by the menu bar when the user clicks on the respective item or presses the specified shortcut key. Use TQMenuBar::insertItem() to insert a popup menu into a menu bar. Show a context menu either asynchronously with popup() or synchronously with exec().
Technically, a popup menu consists of a list of menu items. You add items with insertItem(). An item is either a string, a pixmap or a custom item that provides its own drawing function (see QCustomMenuItem). In addition, items can have an optional icon drawn on the very left side and an accelerator key such as" Ctrl+X".
There are three kinds of menu items: separators, menu items that perform an action and menu items that show a submenu. Separators are inserted with insertSeparator(). For submenus, you pass a pointer to a TQPopupMenu in your call to insertItem(). All other items are considered action items.
When inserting action items you usually specify a receiver and a slot. The receiver will be notifed whenever the item is selected. In addition, TQPopupMenu provides two signals, activated() and highlighted(), which signal the identifier of the respective menu item. It is sometimes practical to connect several items to one slot. To distinguish between them, specify a slot that takes an integer argument and use setItemParameter() to associate a unique value with each item.
You clear a popup menu with clear() and remove single items with removeItem() or removeItemAt().
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A popup menu can display check marks for certain items when enabled with setCheckable(TRUE). You check or uncheck items with setItemChecked().
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Items are either enabled or disabled. You toggle their state with setItemEnabled(). Just before a popup menu becomes visible, it emits the aboutToShow() signal. You can use this signal to set the correct enabled/disabled states of all menu items before the user sees it. The corresponding aboutToHide() signal is emitted when the menu hides again.
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You can provide What's This? help for single menu items with setWhatsThis(). See QWhatsThis for general information about this kind of lightweight online help.
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For ultimate flexibility, you can also add entire widgets as items into a popup menu (for example, a color selector).
A TQPopupMenu can also provide a tear-off menu. A tear-off menu is a top-level window that contains a copy of the menu. This makes it possible for the user to "tear off" frequently used menus and position them in a convenient place on the screen. If you want that functionality for a certain menu, insert a tear-off handle with insertTearOffHandle(). When using tear-off menus, bear in mind that the concept isn't typically used on Microsoft Windows so users may not be familiar with it. Consider using a TQToolBar instead. Tear-off menus cannot contain custom widgets; if the original menu contains a custom widget item, this item is omitted.
Although a popup menu is always a top-level widget, if a parent is passed the popup menu will be deleted when that parent is destroyed (as with any other TQObject).
This signal is emitted just before the popup menu is displayed. You can connect it to any slot that sets up the menu contents (e.g. to ensure that the right items are enabled).
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See also aboutToHide(), setItemEnabled(), setItemChecked(), insertItem(), and removeItem().
Normally, you connect each menu item to a single slot using TQMenuData::insertItem(), but sometimes you will want to connect several items to a single slot (most often if the user selects from an array). This signal is useful in such cases.
If a popup menu does not fit on the screen it lays itself out so that it does fit. It is style dependent what layout means (for example, on Windows it will use multiple columns).
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This functions returns the number of columns necessary.
Draws menu item \fImi\fR in the area \fIx\fR, \fIy\fR, \fIw\fR, \fIh\fR, using painter \fIp\fR. The item is drawn active if \fIact\fR is TRUE or drawn inactive if \fIact\fR is FALSE. The rightmost \fItab_\fR pixels are used for accelerator text.
This is equivalent to \fCexec(mapToGlobal(QPoint(0,0)))\fR. In most situations you'll want to specify the position yourself, for example at the current mouse position:
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exec(QCursor::pos());
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or aligned to a widget:
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exec(somewidget.mapToGlobal(QPoint(0,0)));
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Examples:
.)l fileiconview/qfileiconview.cpp, menu/menu.cpp, and scribble/scribble.cpp.
Opens the popup menu so that the item number \fIindexAtPoint\fR will be at the specified \fIglobal\fR position \fIpos\fR. To translate a widget's local coordinates into global coordinates, use TQWidget::mapToGlobal().
The return code is the id of the selected item in either the popup menu or one of its submenus, or -1 if no item is selected (normally because the user pressed Esc).
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Note that all signals are emitted as usual. If you connect a menu item to a slot and call the menu's exec(), you get the result both via the signal-slot connection and in the return value of exec().
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Common usage is to position the popup at the current mouse position:
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exec( QCursor::pos() );
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or aligned to a widget:
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exec( somewidget.mapToGlobal(QPoint(0, 0)) );
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When positioning a popup with exec() or popup(), bear in mind that you cannot rely on the popup menu's current size(). For performance reasons, the popup adapts its size only when necessary. So in many cases, the size before and after the show is different. Instead, use sizeHint(). It calculates the proper size depending on the menu's current contents.
The family of insertItem() functions inserts menu items into a popup menu or a menu bar.
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A menu item is usually either a text string or a pixmap, both with an optional icon or keyboard accelerator. For special cases it is also possible to insert custom items (see QCustomMenuItem) or even widgets into popup menus.
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Some insertItem() members take a popup menu as an additional argument. Use this to insert submenus into existing menus or pulldown menus into a menu bar.
This default version inserts a menu item with the text \fItext\fR, the accelerator key \fIaccel\fR, an id and an optional index and connects it to the slot \fImember\fR in the object \fIreceiver\fR.
The \fIid\fR specifies the identification number associated with the menu item. Note that only positive values are valid, as a negative value will make TQt select a unique id for the item.
Note that keyboard accelerators in TQt are not application-global, instead they are bound to a certain top-level window. For example, accelerators in TQPopupMenu items only work for menus that are associated with a certain window. This is true for popup menus that live in a menu bar since their accelerators will then be installed in the menu bar itself. This also applies to stand-alone popup menus that have a top-level widget in their parentWidget() chain. The menu will then install its accelerator object on that top-level widget. For all other cases use an independent QAccel object.
\fBWarning:\fR Be careful when passing a literal 0 to insertItem() because some C++ compilers choose the wrong overloaded function. Cast the 0 to what you mean, e.g. \fC(TQObject*)0\fR.
\fBWarning:\fR On Mac OS X, items that connect to a slot that are inserted into a menubar will not function as we use the native menubar that knows nothing about signals or slots. Instead insert the items into a popup menu and insert the popup menu into the menubar. This may be fixed in a future TQt version.
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, text \fItext\fR, accelerator \fIaccel\fR, optional id \fIid\fR, and optional \fIindex\fR position. The menu item is connected it to the \fIreceiver\fR's \fImember\fR slot. The icon will be displayed to the left of the text in the item.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with pixmap \fIpixmap\fR, accelerator \fIaccel\fR, optional id \fIid\fR, and optional \fIindex\fR position. The menu item is connected it to the \fIreceiver\fR's \fImember\fR slot. The icon will be displayed to the left of the text in the item.
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To look best when being highlighted as a menu item, the pixmap should provide a mask (see QPixmap::mask()).
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, pixmap \fIpixmap\fR, accelerator \fIaccel\fR, optional id \fIid\fR, and optional \fIindex\fR position. The icon will be displayed to the left of the pixmap in the item. The item is connected to the \fImember\fR slot in the \fIreceiver\fR object.
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To look best when being highlighted as a menu item, the pixmap should provide a mask (see QPixmap::mask()).
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, text \fItext\fR, optional id \fIid\fR, and optional \fIindex\fR position. The icon will be displayed to the left of the text in the item.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with text \fItext\fR, submenu \fIpopup\fR, optional id \fIid\fR, and optional \fIindex\fR position.
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The \fIpopup\fR must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, text \fItext\fR, submenu \fIpopup\fR, optional id \fIid\fR, and optional \fIindex\fR position. The icon will be displayed to the left of the text in the item.
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The \fIpopup\fR must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, pixmap \fIpixmap\fR, optional id \fIid\fR, and optional \fIindex\fR position. The icon will be displayed to the left of the pixmap in the item.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with pixmap \fIpixmap\fR, submenu \fIpopup\fR, optional id \fIid\fR, and optional \fIindex\fR position.
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The \fIpopup\fR must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
This is an overloaded member function, provided for convenience. It behaves essentially like the above function.
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Inserts a menu item with icon \fIicon\fR, pixmap \fIpixmap\fR submenu \fIpopup\fR, optional id \fIid\fR, and optional \fIindex\fR position. The icon will be displayed to the left of the pixmap in the item.
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The \fIpopup\fR must be deleted by the programmer or by its parent widget. It is not deleted when this menu item is removed or when the menu is deleted.
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Returns the allocated menu identifier number (\fIid\fR if \fIid\fR >= 0).
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See also removeItem(), changeItem(), setAccel(), and connectItem().
If a widget is not focus-enabled (see TQWidget::isFocusEnabled()), the menu treats it as a separator; this means that the item is not selectable and will never get focus. In this way you can, for example, simply insert a QLabel if you need a popup menu with a title.
If the widget is focus-enabled it will get focus when the user traverses the popup menu with the arrow keys. If the widget does not accept \fCArrowUp\fR and \fCArrowDown\fR in its key event handler, the focus will move back to the menu when the respective arrow key is hit one more time. This works with a QLineEdit, for example. If the widget accepts the arrow key itself, it must also provide the possibility to put the focus back on the menu again by calling TQWidget::focusNextPrevChild(). Futhermore, if the embedded widget closes the menu when the user made a selection, this can be done safely by calling:
Inserts a separator at position \fIindex\fR, and returns the menu identifier number allocated to it. The separator becomes the last menu item if \fIindex\fR is negative.
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In a popup menu a separator is rendered as a horizontal line. In a Motif menu bar a separator is spacing, so the rest of the items (normally just "Help") are drawn right-justified. In a Windows menu bar separators are ignored (to comply with the Windows style guidelines).
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Examples:
.)l addressbook/mainwindow.cpp, menu/menu.cpp, progress/progress.cpp, qwerty/qwerty.cpp, scrollview/scrollview.cpp, showimg/showimg.cpp, and sound/sound.cpp.
Inserts a tear-off handle into the menu. A tear-off handle is a special menu item that creates a copy of the menu when the menu is selected. This "torn-off" copy lives in a separate window. It contains the same menu items as the original menu, with the exception of the tear-off handle.
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The handle item is assigned the identifier \fIid\fR or an automatically generated identifier if \fIid\fR is < 0. The generated identifiers (negative integers) are guaranteed to be unique within the entire application.
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The \fIindex\fR specifies the position in the menu. The tear-off handle is appended at the end of the list if \fIindex\fR is negative.
Displays the popup menu so that the item number \fIindexAtPoint\fR will be at the specified \fIglobal\fR position \fIpos\fR. To translate a widget's local coordinates into global coordinates, use TQWidget::mapToGlobal().
When positioning a popup with exec() or popup(), bear in mind that you cannot rely on the popup menu's current size(). For performance reasons, the popup adapts its size only when necessary, so in many cases, the size before and after the show is different. Instead, use sizeHint(). It calculates the proper size depending on the menu's current contents.
An accelerator key consists of a key code and a combination of the modifiers SHIFT, CTRL, ALT or UNICODE_ACCEL (OR'ed or added). The header file ntqnamespace.h contains a list of key codes.
Defining an accelerator key produces a text that is added to the menu item; for instance, CTRL + Key_O produces "Ctrl+O". The text is formatted differently for different platforms.
Note that keyboard accelerators in TQt are not application-global, instead they are bound to a certain top-level window. For example, accelerators in TQPopupMenu items only work for menus that are associated with a certain window. This is true for popup menus that live in a menu bar since their accelerators will then be installed in the menu bar itself. This also applies to stand-alone popup menus that have a top-level widget in their parentWidget() chain. The menu will then install its accelerator object on that top-level widget. For all other cases use an independent QAccel object.
.SH "void TQMenuData::setItemChecked ( int id, bool check )"
If \fIcheck\fR is TRUE, checks the menu item with id \fIid\fR; otherwise unchecks the menu item with id \fIid\fR. Calls TQPopupMenu::setCheckable( TRUE ) if necessary.
