In this section, we are going to port an existing Qt application to iOS and deploy it to the device.
Most Qt applications should be portable to iOS with ease, unless they depend on a specific hardware or software feature not supported on iOS. A major part of the porting effort consists of ensuring that all the application's assets (for example, QML files, images, and icons) are deployed correctly to the device.
Like most UI applications, Qt applications also depend on resources such as images, icons, translation files, and so on. These resources must be made available on the device as they are required for the application to function correctly.
The most convenient option is to bundle the resources into a qrc file, which gets built into the application binary. This approach reduces the porting effort considerably and provides faster access to the resources. It is also a cross-platform approach, which makes porting to other platforms easier.
By default, all Qt applications can access the contents of a qrc file using the ":/" prefix or the URL scheme prefix, "qrc:". To know more about qrc files and how they are handled, see the Qt Resource System.
The following step-by-step instructions guide you to port an existing Qt Quick application to iOS using the qrc approach:
qmlfiles to use a local namespace. For example, to import the QML documents in the "contents" directory relative to
main.qml, use the following import statement:
import "contents" as Contents
RESOURCESvariable, listing the qrc files you added.
qrc:" prefix for the URL. For example:
QQuickView viewer; viewer.setSource(QUrl("qrc:qml/main.qml")); viewer.show();
Note: QML documents can refer to files in the resources simply by using the relative path to the document. Such references do not require the "
qrc:" or "
QT += multimedia
In Qt for iOS, everything is compiled statically and placed into the application bundle. The applications are "sandboxed" inside their bundles and cannot make use of shared object files. Because of this, also the plugins used by the Qt modules need to be statically linked. To do this, define the required plugins using the QTPLUGIN variable. For example, to use the camera APIs from Qt Multimedia:
QTPLUGIN += qavfcamera
QT += sensors QTPLUGIN += qtsensors_ios
Qt Creator deploys your application on the iOS device, if the device is detected and configured correctly in Xcode. It is also possible to test the application in iOS Simulator. For more information, see Connecting iOS Devices.
See also Platform Notes - iOS.
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