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133 lines
5.0 KiB
133 lines
5.0 KiB
/*!
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\page toplevel-example.html
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\ingroup examples
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\title Toplevel Widgets
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This example demonstrates the use of Qt's widget flags to provide
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toplevel widgets with customized window decorations.
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It provides a graphical user interface for selecting different
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options for widget decoration and behavior, and passes the
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appropriate widget flags to the QWidget constructor.
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QWidget::reparent() is used to change the widget flags at runtime.
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\warning Note that the interpretation and functionality of the
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widget flags depends on the window manager used when running the
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application. Many window managers do not support every possible flag
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combination.
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The user interface providing the different options was created using
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\link designer-manual.book TQt Designer\endlink. The different
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options are explained in the user interface through the use of
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tooltips and What's This help. Load the \c options.ui file into
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\link designer-manual.book TQt Designer\endlink for more details.
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\quotefile toplevel/main.cpp
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\printuntil }
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The main function creates and displays the dialog for the user
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interface. Note that this dialog is modal.
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The code relevant for this example is in the \c options.ui.h
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file.
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\quotefile toplevel/options.ui.h
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\printuntil WFlags
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The \c apply() slot declares the widget flag variable \c f
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and initializes it with the values
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\list
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\i \c WDestructiveClose - the widget will be automatically
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destroyed when it is closed,
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\i \c WType_TopLevel - the widget will be top level even if it
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has a parent widget, and
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\i \c WStyle_Customize - the flags override the default values
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\endlist
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Other flags are used depending on the options selected in the user
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interface.
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\printto bgTitle->isChecked()
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The window gets a normal or dialog border depending on the selected
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option.
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\printto else
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A titlebar with controls is provided if the appropriate options
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have been checked.
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\printto QWidget *parent
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If the window should not have a border it cannot have a titlebar.
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Widgets that provide their own (e.g. themed) window decoration
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should use this flag.
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\printto cbBehaviorStays
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If a toplevel widget has a parent it will not have a taskbar
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entry, and on most window managers it will always stay on
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top of the parent widget. This is the standard behavior for
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dialog boxes, especially if they are modeless, and for other
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secondary toplevel widgets.
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To provide a taskbar entry the widget must have no parent,
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in which case we need to use the \c WGroupLeader flag to
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prevent blocking through the modal main dialog. Applications
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that can have multiple toplevel windows open simultaneously
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should use this combination.
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\printto cbBehaviorPopup
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A toplevel widget can stay on top of the whole desktop if the
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window manager supports this functionality.
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\footnote Unfortunately some X11 window managers also require the \c
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WX11BypassWM flag to be set in addition; but some other X11 window
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managers will have problems if this flag is set. \endfootnote
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Widgets that display important or realtime information (i.e. IRC
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clients) might benefit from using that flag.
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\printto cbBehaviorModal
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A popup widget is a short lived modal widget that closes
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automatically. Popup menus are a typical example for such widgets.
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\printto cbBehaviorTool
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A modal widget blocks input to other toplevel widgets, unless
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those are in a different modal group (see \c WGroupLeader).
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Dialogs are often modal, and the QDialog class provides an easy API
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to create and display them without the need to explicitly use this
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flag.
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\printto !widget
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A tool window will never have a task bar entry (even if it
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has no parent widget), and often has a smaller window
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decoration. Tool windows are frequently used instead of
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modeless dialogs.
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\printto else
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The widget is created if it has not been created yet, or if it was
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closed (since we use the \c WDestructiveClose flag). Note that the
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window is not visible yet.
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\footnote The example uses QGuardedPtr to make sure that the
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pointer is reset to zero when the widget object is destroyed
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due to the \c WDestructiveClose flag. \endfootnote
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\printto setCaption
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If the widget has already been created the reparent() function is
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used to modify the widget's flags. The widget's geometry is not
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changed, and the window is not shown again.
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\printuntil show()
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Finally the higher level properties such as the window's caption and
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icon are set. The window transparency is set according to the slider
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value. Note that this will only have effect on systems that support
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this attribute for toplevel window.
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\printuntil }
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Finally the window is shown with the new attributes.
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To build the example go to the toplevel directory
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(\c TQTDIR/examples/toplevel)
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\footnote
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We use \c TQTDIR to stand for the directory where TQt is installed.
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\endfootnote
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and run \c qmake to generate the makefile, then use the make tool to
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build the library.
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*/
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