- Qt 6.12
- Qt Widgets Designer Manual
- C++ Classes
- QDesignerFormWindowInterface
- Qt 6.12.0 Reference Documentation

# QDesignerFormWindowInterface Class

The QDesignerFormWindowInterface class allows you to query and manipulate form windows appearing in Qt Widgets Designer's workspace. More...

Header: | `#include <QDesignerFormWindowInterface>`
CMake: | `find_package(Qt6 REQUIRED COMPONENTS Designer)` `target_link_libraries(mytarget PRIVATE Qt6::Designer)`
qmake: | `QT += designer`
Inherits: | QWidget

- List of all members, including inherited members

## Public Types

flags | Feature
enum | FeatureFlag { EditFeature, GridFeature, TabOrderFeature, DefaultFeature }
enum | ResourceFileSaveMode { SaveAllResourceFiles, SaveOnlyUsedResourceFiles, DontSaveResourceFiles }

## Public Functions

| QDesignerFormWindowInterface(QWidget *parent = nullptr, Qt::WindowFlags flags = {})
virtual | ~QDesignerFormWindowInterface()
virtual QDir | absoluteDir() const = 0
QStringList | activeResourceFilePaths() const
virtual void | addResourceFile(const QString &path) = 0
virtual QString | author() const = 0
virtual QStringList | checkContents() const = 0
virtual QString | comment() const = 0
virtual QString | contents() const = 0
virtual QDesignerFormEditorInterface * | core() const
virtual QDesignerFormWindowCursorInterface * | cursor() const = 0
virtual void | emitSelectionChanged() = 0
virtual QString | exportMacro() const = 0
virtual QDesignerFormWindowInterface::Feature | features() const = 0
virtual QString | fileName() const = 0
virtual QWidget * | formContainer() const = 0
virtual QPoint | grid() const = 0
virtual bool | hasFeature(QDesignerFormWindowInterface::Feature feature) const = 0
virtual QStringList | includeHints() const = 0
virtual bool | isDirty() const = 0
virtual bool | isManaged(QWidget *widget) const = 0
virtual void | layoutDefault(int *margin, int *spacing) = 0
virtual void | layoutFunction(QString *margin, QString *spacing) = 0
virtual QString | pixmapFunction() const = 0
virtual void | removeResourceFile(const QString &path) = 0
virtual QDesignerFormWindowInterface::ResourceFileSaveMode | resourceFileSaveMode() const = 0
virtual QStringList | resourceFiles() const = 0
virtual void | setAuthor(const QString &author) = 0
virtual void | setComment(const QString &comment) = 0
virtual bool | setContents(QIODevice *device, QString *errorMessage = 0) = 0
virtual void | setExportMacro(const QString &exportMacro) = 0
virtual void | setIncludeHints(const QStringList &includeHints) = 0
virtual void | setLayoutDefault(int margin, int spacing) = 0
virtual void | setLayoutFunction(const QString &margin, const QString &spacing) = 0
virtual void | setMainContainer(QWidget *mainContainer) = 0
virtual void | setPixmapFunction(const QString &pixmapFunction) = 0
virtual void | setResourceFileSaveMode(QDesignerFormWindowInterface::ResourceFileSaveMode behavior) = 0

## Public Slots

void | activateResourceFilePaths(const QStringList &paths, int *errorCount = nullptr, QString *errorMessages = nullptr)
virtual void | clearSelection(bool update = true) = 0
virtual void | manageWidget(QWidget *widget) = 0
virtual void | selectWidget(QWidget *widget, bool select = true) = 0
virtual bool | setContents(const QString &contents) = 0
virtual void | setDirty(bool dirty) = 0
virtual void | setFeatures(QDesignerFormWindowInterface::Feature features) = 0
virtual void | setFileName(const QString &fileName) = 0
virtual void | setGrid(const QPoint &grid) = 0
virtual void | unmanageWidget(QWidget *widget) = 0

## Signals

void | aboutToUnmanageWidget(QWidget *widget)
void | activated(QWidget *widget)
void | changed()
void | featureChanged(QDesignerFormWindowInterface::Feature feature)
void | fileNameChanged(const QString &fileName)
void | geometryChanged()
void | mainContainerChanged(QWidget *mainContainer)
void | objectRemoved(QObject *object)
void | resourceFilesChanged()
void | selectionChanged()
void | widgetManaged(QWidget *widget)
void | widgetRemoved(QWidget *widget)
void | widgetUnmanaged(QWidget *widget)

## Static Public Members

QDesignerFormWindowInterface * | findFormWindow(QObject *object)
QDesignerFormWindowInterface * | findFormWindow(QWidget *widget)

## Detailed Description

QDesignerFormWindowInterface provides information about the associated form window as well as allowing its properties to be altered. The interface is not intended to be instantiated directly, but to provide access to Qt Widgets Designer's current form windows controlled by Qt Widgets Designer's form window manager.

If you are looking for the form window containing a specific widget, you can use the static QDesignerFormWindowInterface::findFormWindow() function:

         auto *formWindow = QDesignerFormWindowInterface::findFormWindow(myWidget);

But in addition, you can access any of the current form windows through Qt Widgets Designer's form window manager: Use the QDesignerFormEditorInterface::formWindowManager() function to retrieve an interface to the manager. Once you have this interface, you have access to all of Qt Widgets Designer's current form windows through the QDesignerFormWindowManagerInterface::formWindow() function. For example:

         QList<QDesignerFormWindowInterface *> forms;

         auto *manager = formEditor->formWindowManager();

         for (int i = 0; i < manager->formWindowCount(); ++i)
             forms.append(manager->formWindow(i));

The pointer to Qt Widgets Designer's current QDesignerFormEditorInterface object (`formEditor` in the example above) is provided by the QDesignerCustomWidgetInterface::initialize() function's parameter. When implementing a custom widget plugin, you must subclass the QDesignerCustomWidgetInterface class to expose your plugin to Qt Widgets Designer.

Once you have the form window, you can query its properties. For example, a plain custom widget plugin is managed by Qt Widgets Designer only at its top level, i.e. none of its child widgets can be resized in Qt Widgets Designer's workspace. But QDesignerFormWindowInterface provides you with functions that enables you to control whether a widget should be managed by Qt Widgets Designer, or not:

             if (formWindow->isManaged(myWidget))
                 formWindow->manageWidget(myWidget->childWidget);

The complete list of functions concerning widget management is: isManaged(), manageWidget() and unmanageWidget(). There is also several associated signals: widgetManaged(), widgetRemoved(), aboutToUnmanageWidget() and widgetUnmanaged().

In addition to controlling the management of widgets, you can control the current selection in the form window using the selectWidget(), clearSelection() and emitSelectionChanged() functions, and the selectionChanged() signal.

You can also retrieve information about where the form is stored using absoluteDir(), its include files using includeHints(), and its layout and pixmap functions using layoutDefault(), layoutFunction() and pixmapFunction(). You can find out whether the form window has been modified (but not saved) or not, using the isDirty() function. You can retrieve its author(), its contents(), its fileName(), associated comment() and exportMacro(), its mainContainer(), its features(), its grid() and its resourceFiles().

The interface provides you with functions and slots allowing you to alter most of this information as well. The exception is the directory storing the form window. Finally, there is several signals associated with changes to the information mentioned above and to the form window in general.

See also QDesignerFormWindowCursorInterface, QDesignerFormEditorInterface, and QDesignerFormWindowManagerInterface.

## Member Type Documentation

### enum QDesignerFormWindowInterface::FeatureFlag
flags QDesignerFormWindowInterface::Feature

This enum describes the features that are available and can be controlled by the form window interface. These values are used when querying the form window to determine which features it supports:

Constant | Value | Description
--- | --- | ---
`QDesignerFormWindowInterface::EditFeature` | `0x01` | Form editing
`QDesignerFormWindowInterface::GridFeature` | `0x02` | Grid display and snap-to-grid facilities for editing
`QDesignerFormWindowInterface::TabOrderFeature` | `0x04` | Tab order management
`QDesignerFormWindowInterface::DefaultFeature` | `EditFeature | GridFeature` | Support for default features (form editing and grid)

The Feature type is a typedef for QFlags<FeatureFlag>. It stores an OR combination of FeatureFlag values.

See also hasFeature() and features().

### enum QDesignerFormWindowInterface::ResourceFileSaveMode

This enum describes how resource files are saved.

Constant | Value | Description
--- | --- | ---
`QDesignerFormWindowInterface::SaveAllResourceFiles` | `0` | Save all resource files.
`QDesignerFormWindowInterface::SaveOnlyUsedResourceFiles` | `1` | Save resource files used by form.
`QDesignerFormWindowInterface::DontSaveResourceFiles` | `2` | Do not save resource files.

## Member Function Documentation

### `[explicit]` QDesignerFormWindowInterface::QDesignerFormWindowInterface(QWidget *parent = nullptr, Qt::WindowFlags flags = {})

Constructs a form window interface with the given parent and the specified window flags.

### `[virtual noexcept]` QDesignerFormWindowInterface::~QDesignerFormWindowInterface()

Destroys the form window interface.

### `[signal]` void QDesignerFormWindowInterface::aboutToUnmanageWidget(QWidget *widget)

This signal is emitted whenever a widget on the form is about to become unmanaged. When this signal is emitted, the specified widget is still managed, and a widgetUnmanaged() signal will follow, indicating when it is no longer managed.

See also unmanageWidget() and isManaged().

### `[pure virtual]` QDir QDesignerFormWindowInterface::absoluteDir() const

Returns the absolute location of the directory containing the form shown in the form window.

### `[slot]` void QDesignerFormWindowInterface::activateResourceFilePaths(const QStringList &paths, int *errorCount = nullptr, QString *errorMessages = nullptr)

Activates the resource (.qrc) file paths paths, returning the count of errors in errorCount and error message in errorMessages. Qt Widgets Designer loads the resources using the QResource class, making them available for form editing.

In IDE integrations, a list of the project's resource (.qrc) file can be activated, making them available to Qt Widgets Designer.

See also activeResourceFilePaths() and QResource.

### `[signal]` void QDesignerFormWindowInterface::activated(QWidget *widget)

This signal is emitted whenever a widget is activated on the form. The activated widget is specified by widget.

### QStringList QDesignerFormWindowInterface::activeResourceFilePaths() const

Returns the active resource (.qrc) file paths currently loaded in Qt Widgets Designer.

See also activateResourceFilePaths().

### `[pure virtual]` void QDesignerFormWindowInterface::addResourceFile(const QString &path)

Adds the resource file at the given path to those used by the form.

See also resourceFiles() and resourceFilesChanged().

### `[pure virtual]` QString QDesignerFormWindowInterface::author() const

Returns details of the author or creator of the form currently being displayed in the window.

See also setAuthor().

### `[signal]` void QDesignerFormWindowInterface::changed()

This signal is emitted whenever a form is changed.

### `[pure virtual]` QStringList QDesignerFormWindowInterface::checkContents() const

Performs checks on the current form and returns a list of richtext warnings about potential issues (for example, top level spacers on unlaid-out forms).

IDE integrations can call this before handling starting a save operation.

### `[pure virtual slot]` void QDesignerFormWindowInterface::clearSelection(bool update = true)

Clears the current selection in the form window. If update is true, the emitSelectionChanged() function is called, emitting the selectionChanged() signal.

See also selectWidget().

### `[pure virtual]` QString QDesignerFormWindowInterface::comment() const

Returns comments about the form currently being displayed in the window.

See also setComment().

### `[pure virtual]` QString QDesignerFormWindowInterface::contents() const

Returns details of the contents of the form currently being displayed in the window.

See also setContents().

### `[virtual]` QDesignerFormEditorInterface *QDesignerFormWindowInterface::core() const

Returns a pointer to Qt Widgets Designer's current QDesignerFormEditorInterface object.

### `[pure virtual]` QDesignerFormWindowCursorInterface *QDesignerFormWindowInterface::cursor() const

Returns the cursor interface used by the form window.

### `[pure virtual]` void QDesignerFormWindowInterface::emitSelectionChanged()

Emits the selectionChanged() signal.

See also selectWidget() and clearSelection().

### `[pure virtual]` QString QDesignerFormWindowInterface::exportMacro() const

Returns the export macro associated with the form currently being displayed in the window. The export macro is used when the form is compiled to create a widget plugin.

See also setExportMacro() and Creating Custom Widgets for Qt Widgets Designer.

### `[signal]` void QDesignerFormWindowInterface::featureChanged(QDesignerFormWindowInterface::Feature feature)

This signal is emitted whenever a feature changes in the form. The new feature is specified by feature.

See also setFeatures().

### `[pure virtual]` QDesignerFormWindowInterface::Feature QDesignerFormWindowInterface::features() const

Returns a combination of the features provided by the form window associated with the interface. The value returned can be tested against the Feature enum values to determine which features are supported by the window.

See also setFeatures() and hasFeature().

### `[pure virtual]` QString QDesignerFormWindowInterface::fileName() const

Returns the file name of the UI file that describes the form currently being shown.

See also setFileName().

### `[signal]` void QDesignerFormWindowInterface::fileNameChanged(const QString &fileName)

This signal is emitted whenever the file name of the form changes. The new file name is specified by fileName.

See also setFileName().

### `[static]` QDesignerFormWindowInterface *QDesignerFormWindowInterface::findFormWindow(QObject *object)

Returns the form window interface for the given object.

### `[static]` QDesignerFormWindowInterface *QDesignerFormWindowInterface::findFormWindow(QWidget *widget)

Returns the form window interface for the given widget.

### `[pure virtual]` QWidget *QDesignerFormWindowInterface::formContainer() const

Returns the form the widget containing the main container widget.

### `[signal]` void QDesignerFormWindowInterface::geometryChanged()

This signal is emitted whenever the form's geometry changes.

### `[pure virtual]` QPoint QDesignerFormWindowInterface::grid() const

Returns the grid spacing used by the form window.

See also setGrid().

### `[pure virtual]` bool QDesignerFormWindowInterface::hasFeature(QDesignerFormWindowInterface::Feature feature) const

Returns true if the form window offers the specified feature; otherwise returns false.

See also features().

### `[pure virtual]` QStringList QDesignerFormWindowInterface::includeHints() const

Returns a list of the header files that will be included in the form window's associated UI file.

Header files may be local, i.e. relative to the project's directory, `"mywidget.h"`, or global, i.e. part of Qt or the compilers standard libraries: `<QtGui/QWidget>`.

See also setIncludeHints().

### `[pure virtual]` bool QDesignerFormWindowInterface::isDirty() const

Returns true if the form window is "dirty" (modified but not saved); otherwise returns false.

See also setDirty().

### `[pure virtual]` bool QDesignerFormWindowInterface::isManaged(QWidget *widget) const

Returns true if the specified widget is managed by the form window; otherwise returns false.

See also manageWidget().

### `[pure virtual]` void QDesignerFormWindowInterface::layoutDefault(int *margin, int *spacing)

Fills in the default margin and spacing for the form's default layout in the margin and spacing variables specified.

See also setLayoutDefault().

### `[pure virtual]` void QDesignerFormWindowInterface::layoutFunction(QString *margin, QString *spacing)

Fills in the current margin and spacing for the form's layout in the margin and spacing variables specified.

See also setLayoutFunction().

### `[signal]` void QDesignerFormWindowInterface::mainContainerChanged(QWidget *mainContainer)

This signal is emitted whenever the main container changes. The new container is specified by mainContainer.

See also setMainContainer().

### `[pure virtual slot]` void QDesignerFormWindowInterface::manageWidget(QWidget *widget)

Instructs the form window to manage the specified widget.

See also isManaged(), unmanageWidget(), and widgetManaged().

### `[signal]` void QDesignerFormWindowInterface::objectRemoved(QObject *object)

This signal is emitted whenever an object (such as an action or a QButtonGroup) is removed from the form. The object that was removed is specified by object.

### `[pure virtual]` QString QDesignerFormWindowInterface::pixmapFunction() const

Returns the name of the function used to load pixmaps into the form window.

See also setPixmapFunction().

### `[pure virtual]` void QDesignerFormWindowInterface::removeResourceFile(const QString &path)

Removes the resource file at the specified path from the list of those used by the form.

See also resourceFiles() and resourceFilesChanged().

### `[pure virtual]` QDesignerFormWindowInterface::ResourceFileSaveMode QDesignerFormWindowInterface::resourceFileSaveMode() const

Returns the resource file save mode behavior.

See also setResourceFileSaveMode().

### `[pure virtual]` QStringList QDesignerFormWindowInterface::resourceFiles() const

Returns a list of paths to resource files that are currently being used by the form window.

See also addResourceFile() and removeResourceFile().

### `[signal]` void QDesignerFormWindowInterface::resourceFilesChanged()

This signal is emitted whenever the list of resource files used by the form changes.

See also resourceFiles().

### `[pure virtual slot]` void QDesignerFormWindowInterface::selectWidget(QWidget *widget, bool select = true)

If select is true, the given widget is selected; otherwise the widget is deselected.

See also clearSelection() and selectionChanged().

### `[signal]` void QDesignerFormWindowInterface::selectionChanged()

This signal is emitted whenever the selection in the form changes.

See also selectWidget() and clearSelection().

### `[pure virtual]` void QDesignerFormWindowInterface::setAuthor(const QString &author)

Sets the details for the author or creator of the form to the author specified.

See also author().

### `[pure virtual]` void QDesignerFormWindowInterface::setComment(const QString &comment)

Sets the information about the form to the comment specified. This information should be a human-readable comment about the form.

See also comment().

### `[pure virtual slot]` bool QDesignerFormWindowInterface::setContents(const QString &contents)

Sets the contents of the form using data read from the specified contents string and returns whether the operation succeeded.

Note: This slot is overloaded. To connect to this slot:

     // Connect using qOverload:
     connect(sender, &SenderClass::signal,
             designerFormWindowInterface, qOverload(&QDesignerFormWindowInterface::setContents));

     // Or using a lambda as wrapper:
     connect(sender, &SenderClass::signal,
             designerFormWindowInterface, [receiver = designerFormWindowInterface](const QString &contents) { receiver->setContents(contents); });

For more examples and approaches, see connecting to overloaded slots.

See also contents().

### `[pure virtual]` bool QDesignerFormWindowInterface::setContents(QIODevice *device, QString *errorMessage = 0)

Sets the form's contents using data obtained from the given device and returns whether loading succeeded. If it fails, the error message is returned in errorMessage.

Data can be read from QFile objects or any other subclass of QIODevice.

### `[pure virtual slot]` void QDesignerFormWindowInterface::setDirty(bool dirty)

If dirty is true, the form window is marked as dirty, meaning that it is modified but not saved. If dirty is false, the form window is considered to be unmodified.

See also isDirty().

### `[pure virtual]` void QDesignerFormWindowInterface::setExportMacro(const QString &exportMacro)

Sets the form window's export macro to exportMacro. The export macro is used when building a widget plugin to export the form's interface to other components.

See also exportMacro().

### `[pure virtual slot]` void QDesignerFormWindowInterface::setFeatures(QDesignerFormWindowInterface::Feature features)

Enables the specified features for the form window.

See also features() and featureChanged().

### `[pure virtual slot]` void QDesignerFormWindowInterface::setFileName(const QString &fileName)

Sets the file name for the form to the given fileName.

See also fileName() and fileNameChanged().

### `[pure virtual slot]` void QDesignerFormWindowInterface::setGrid(const QPoint &grid)

Sets the grid size for the form window to the point specified by grid. In this function, the coordinates in the QPoint are used to specify the dimensions of a rectangle in the grid.

See also grid().

### `[pure virtual]` void QDesignerFormWindowInterface::setIncludeHints(const QStringList &includeHints)

Sets the header files that will be included in the form window's associated UI file to the specified includeHints.

Header files may be local, i.e. relative to the project's directory, `"mywidget.h"`, or global, i.e. part of Qt or the compilers standard libraries: `<QtGui/QWidget>`.

See also includeHints().

### `[pure virtual]` void QDesignerFormWindowInterface::setLayoutDefault(int margin, int spacing)

Sets the default margin and spacing for the form's layout.

See also layoutDefault().

### `[pure virtual]` void QDesignerFormWindowInterface::setLayoutFunction(const QString &margin, const QString &spacing)

Sets the margin and spacing for the form's layout.

The default layout properties will be replaced by the corresponding layout functions when `uic` generates code for the form, that is, if the functions are specified. This is useful when different environments requires different layouts for the same form.

See also layoutFunction().

### `[pure virtual]` void QDesignerFormWindowInterface::setMainContainer(QWidget *mainContainer)

Sets the main container widget on the form to the specified mainContainer.

See also mainContainerChanged().

### `[pure virtual]` void QDesignerFormWindowInterface::setPixmapFunction(const QString &pixmapFunction)

Sets the function used to load pixmaps into the form window to the given pixmapFunction.

See also pixmapFunction().

### `[pure virtual]` void QDesignerFormWindowInterface::setResourceFileSaveMode(QDesignerFormWindowInterface::ResourceFileSaveMode behavior)

Sets the resource file save mode behavior.

See also resourceFileSaveMode().

### `[pure virtual slot]` void QDesignerFormWindowInterface::unmanageWidget(QWidget *widget)

Instructs the form window not to manage the specified widget.

See also aboutToUnmanageWidget() and widgetUnmanaged().

### `[signal]` void QDesignerFormWindowInterface::widgetManaged(QWidget *widget)

This signal is emitted whenever a widget on the form becomes managed. The newly managed widget is specified by widget.

See also manageWidget().

### `[signal]` void QDesignerFormWindowInterface::widgetRemoved(QWidget *widget)

This signal is emitted whenever a widget is removed from the form. The widget that was removed is specified by widget.

### `[signal]` void QDesignerFormWindowInterface::widgetUnmanaged(QWidget *widget)

This signal is emitted whenever a widget on the form becomes unmanaged. The newly released widget is specified by widget.

See also unmanageWidget() and aboutToUnmanageWidget().