QQmlApplicationEngine provides a convenient way to load an application from a single QML file. 更多...
Header: | #include <QQmlApplicationEngine> |
qmake: | QT += qml |
Since: | Qt 5.1 |
继承: | QQmlEngine |
QQmlApplicationEngine (QObject * parent = nullptr) | |
QQmlApplicationEngine (const QUrl & url , QObject * parent = nullptr) | |
QQmlApplicationEngine (const QString & filePath , QObject * parent = nullptr) | |
virtual | ~QQmlApplicationEngine () override |
QList<QObject *> | rootObjects () const |
void | load (const QUrl & url ) |
void | load (const QString & filePath ) |
void | loadData (const QByteArray & data , const QUrl & url = QUrl()) |
void | objectCreated (QObject * object , const QUrl & url ) |
const QMetaObject | staticMetaObject |
QQmlApplicationEngine provides a convenient way to load an application from a single QML file.
此类结合 QQmlEngine and QQmlComponent to provide a convenient way to load a single QML file. It also exposes some central application functionality to QML, which a C++/QML hybrid application would normally control from C++.
It can be used like so:
#include <QGuiApplication> #include <QQmlApplicationEngine> int main(int argc, char *argv[]) { QGuiApplication app(argc, argv); QQmlApplicationEngine engine("main.qml"); return app.exec(); }
不像 QQuickView , QQmlApplicationEngine does not automatically create a root window. If you are using visual items from Qt Quick, you will need to place them inside of a Window .
You can also use
QCoreApplication
with
QQmlApplicationEngine
, if you are not using any QML modules which require a
QGuiApplication
(譬如
QtQuick
).
List of configuration changes from a default QQmlEngine :
QQmlFileSelector
as the url interceptor, applying file selectors to all QML files and assets.
The engine behavior can be further tweaked by using the inherited methods from QQmlEngine .
Create a new QQmlApplicationEngine with the given parent . You will have to call load () later in order to load a QML file.
Create a new QQmlApplicationEngine and loads the QML file at the given url . This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.
Create a new QQmlApplicationEngine and loads the QML file at the given filePath , which must be a local file path. If a relative path is given then it will be interpreted as relative to the working directory of the application.
This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.
[override virtual]
QQmlApplicationEngine::
~QQmlApplicationEngine
()
销毁 QQmlApplicationEngine and all QML objects it loaded.
[slot]
void
QQmlApplicationEngine::
load
(const
QUrl
&
url
)
Loads the root QML file located at url . The object tree defined by the file is created immediately for local file urls. Remote urls are loaded asynchronously, listen to the objectCreated signal to determine when the object tree is ready.
If an error occurs, the objectCreated signal is emitted with a null pointer as parameter and error messages are printed with qWarning .
[slot]
void
QQmlApplicationEngine::
load
(const
QString
&
filePath
)
Loads the root QML file located at filePath . filePath must be a path to a local file. If filePath is a relative path, it is taken as relative to the application's working directory. The object tree defined by the file is instantiated immediately.
If an error occurs, error messages are printed with qWarning .
[slot]
void
QQmlApplicationEngine::
loadData
(const
QByteArray
&
data
, const
QUrl
&
url
= QUrl())
Loads the QML given in data . The object tree defined by data is instantiated immediately.
若 url is specified it is used as the base url of the component. This affects relative paths within the data and error messages.
If an error occurs, error messages are printed with qWarning .
[signal]
void
QQmlApplicationEngine::
objectCreated
(
QObject
*
object
, const
QUrl
&
url
)
This signal is emitted when an object finishes loading. If loading was successful, object contains a pointer to the loaded object, otherwise the pointer is NULL.
url to the component the object came from is also provided.
注意: If the path to the component was provided as a QString containing a relative path, the url will contain a fully resolved path to the file.
Returns a list of all the root objects instantiated by the QQmlApplicationEngine . This will only contain objects loaded via load () or a convenience constructor.
注意:
In Qt versions prior to 5.9, this function is marked as non-
const
.