QUiLoader Class

MyWidget::MyWidget(QWidget *parent)
    : QWidget(parent)
{
    QFile file(":/forms/myform.ui");
    if (!file.open(QFile::ReadOnly))
        qFatal("Cannot open resource file");

    QUiLoader loader;
    QWidget *myWidget = loader.load(&file, this);

    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(myWidget);
    setLayout(layout);
}

QWidget *loadCustomWidget(const QString &className, QWidget *parent)
{
    QUiLoader loader;
    QStringList availableWidgets = loader.availableWidgets();

    if (!availableWidgets.contains(className)) {
        qWarning() << "Cannot create widget" << className;
        return nullptr;
    }

    return loader.createWidget(className, parent);
}

Member Function Documentation

[explicit] QUiLoader::QUiLoader(QObject *parent = nullptr)

Creates a form loader with the given parent.

[override virtual noexcept] QUiLoader::~QUiLoader()

Destroys the loader.

void QUiLoader::addPluginPath(const QString &path)

Adds the given path to the list of paths in which the loader will search when locating plugins.

See also pluginPaths() and clearPluginPaths().

QStringList QUiLoader::availableLayouts() const

Returns a list of all available layouts that can be built using the createLayout() function.

See also createLayout().

QStringList QUiLoader::availableWidgets() const

Returns a list of all available widgets that can be built using the createWidget() function, that is, all the widgets specified within the given plugin paths.

See also pluginPaths() and createWidget().

void QUiLoader::clearPluginPaths()

Clears the list of paths in which the loader will search when locating plugins.

See also addPluginPath() and pluginPaths().

[virtual] QAction *QUiLoader::createAction(QObject *parent = nullptr, const QString &name = QString())

Creates a new action with the given parent and name.

The function is also used internally by the QUiLoader class whenever it creates an action. Therefore, you can subclass QUiLoader and reimplement this function to intervene in the process of constructing a user interface or widget. However, in your implementation, ensure that you call QUiLoader's version first.

See also createActionGroup(), createWidget(), and load().

[virtual] QActionGroup *QUiLoader::createActionGroup(QObject *parent = nullptr, const QString &name = QString())

Creates a new action group with the given parent and name.

The function is also used internally by the QUiLoader class whenever it creates an action group. Therefore, you can subclass QUiLoader and reimplement this function to intervene in the process of constructing a user interface or widget. However, in your implementation, ensure that you call QUiLoader's version first.

See also createAction(), createWidget(), and load().

[virtual] QLayout *QUiLoader::createLayout(const QString &className, QObject *parent = nullptr, const QString &name = QString())

Creates a new layout with the given parent and name using the class specified by className.

The function is also used internally by the QUiLoader class whenever it creates a layout. Therefore, you can subclass QUiLoader and reimplement this function to intervene in the process of constructing a user interface or widget. However, in your implementation, ensure that you call QUiLoader's version first.

See also createWidget() and load().

[virtual] QWidget *QUiLoader::createWidget(const QString &className, QWidget *parent = nullptr, const QString &name = QString())

Creates a new widget with the given parent and name using the class specified by className. You can use this function to create any of the widgets returned by the availableWidgets() function.

The function is also used internally by the QUiLoader class whenever it creates a widget. Therefore, you can subclass QUiLoader and reimplement this function to intervene in the process of constructing a user interface or widget. However, in your implementation, ensure that you call QUiLoader's version first.

See also availableWidgets() and load().

QString QUiLoader::errorString() const

Returns a human-readable description of the last error that occurred in load().

See also load().

bool QUiLoader::isLanguageChangeEnabled() const

Returns true if dynamic retranslation on language change is enabled; returns false otherwise.

The default is false.

See also setLanguageChangeEnabled().

QWidget *QUiLoader::load(QIODevice *device, QWidget *parentWidget = nullptr)

Instantiates a form from the given device. Returns a new QWidget with the given parentWidget if successful. Returns nullptr otherwise.

See also createWidget() and errorString().

QStringList QUiLoader::pluginPaths() const

Returns a list naming the paths in which the loader will search when locating custom widget plugins.

See also addPluginPath() and clearPluginPaths().

void QUiLoader::setLanguageChangeEnabled(bool enabled)

If enabled is true, user interfaces loaded by this loader will automatically retranslate themselves upon receiving a language change event. Otherwise, the user interfaces will not be retranslated.

See also isLanguageChangeEnabled().

void QUiLoader::setWorkingDirectory(const QDir &dir)

Sets the working directory of the loader to dir. The loader will look for other resources, such as icons and resource files, in paths relative to this directory.

See also workingDirectory().

QDir QUiLoader::workingDirectory() const

Returns the working directory of the loader.

See also setWorkingDirectory().