How to write plug-in loading plugin uninstall plugin in QT

How to write plug -in loading plugin Uninstall plugin in Qt is the content that this article describes. QT provides a class Qpluginloader to load static and dynamic libraries, and in Qt, QT uses both dynamic and static libraries as a plug-in, using Qpluginloader to load and unload these libraries. Since the development of the project, to develop a set of plug-in systems, the use of this set of QT class library.

Write a plugin

The following steps are required to write a QT plugin

1. Declare a plug-in class,

2. Define a class that implements the interface defined by this plug-in class, which must be integrated from Qobject.

3. Use Q_interfacesq_interfaces () to inform QT of the existence of the meta-system of this interface

3. Use the macro q_export_plugin2 () to export the plug-in interface

4. Write the. Pro file for the plug-in class

Here is an example of a plugin

5.

Note: The interface class must be a pure virtual function

1. Q_declare_interface (Filterinterface, "com.trolltech.plugandpaint.brushinterface/1.0")

In order for the program to query whether a plug-in implements a given interface at run time, the macro q_declare_interface () must be used. His first argument is the name of the interface, and the second parameter is a string that determines the interface. For convenience, a Java package naming method is used. If we later change the interface, we must use a new string to confirm the interface. Otherwise, the application may crash, so including a version number is a good way to do it.

1 #include <QObject>
2 #include <QStringList>
3 #include <QImage>

5 #include <plugandpaint/interfaces.h>



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Implement this interface class. The class that implements the interface must derive from Qobject and must implement the virtual functions defined in the interface class.

Q_export_plugin2 (Plugextrafilters, Extrafiltersplugin) because the application function uses the main () function as the entry point, the plug-in must use the macro q_export_plugin2 () to specify that the class provides the plug-in.

This line of code can appear on any line of the. cpp file that implements the interface class. Where the first parameter is the name of the plug-in, and the second parameter is the plug-in class

Second use plug-in

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The Qpluginloader class provides a function loader to load an instance of a plug-in, if the DLL is not a plugin, or if the compiled Qt version library is incorrect, the pointer to the returned Qobject object is empty. Use the Unload function to unload the plug-in.

Three. Preparation of pro Files

5 TARGET = Pnp_extrafilters

Http://www.cnblogs.com/elect-fans/archive/2012/03/20/2408564.html

How to write plug-in loading plugin uninstall plugin in QT