Qt 插件中的 QObject 工厂（非创建者）

Question

我开始对我的问题感到非常紧张，我会尝试描述我的需求，希望有人理解。 想象一下，我有一个项目，它生成一个可执行文件和一些插件（运行时加载的库）。该可执行文件是某种守护进程/服务，它在一开始就寻找合适的插件。所以这些插件应该提供一些抽象的通信层。 我查看了 Qt Doc，发现 QPluginLoader 类应该提供从 .so 加载的接口，但是接口不能有信号/插槽，必须是纯虚拟的。所以我在想一些会返回基于 QObject 的对象...

！！！请不要害怕，它只有 2 个接口和 2 个实现 :)

我的项目布局和内容：

./Daemon/Interfaces/PluginInterface.h

#include <QObject>
#include "PluginInterface.h"
class PluginInterface {
public:
    virtual ~PluginInterface() = 0;
    virtual ProtocolInterface* getInterface() = 0;
    virtual int getPluginId() const = 0;
};

Q_DECLARE_INTERFACE( PluginInterface, "com.porta.protocol.PluginInterface/1.0")

./Daemon/Interfaces/ProtocolInterface.h

#include <QObject>
#include "turnstile.h"
class ProtocolInterface : public QObject {
    Q_OBJECT
public:
    ProtocolInterface( QObject *parent = 0 ) : QObject( parent ) {}
    virtual QWidget* getConfigureGUI() = 0;
    virtual void init() = 0;
    virtual void start() = 0;
signals:
    void someSignal();
};

./Daemon/ProtocolHander.cpp(&h)

./Daemon.pro

QT       += core gui
TARGET = porta_daemon
CONFIG   += console
CONFIG   -= app_bundle
TEMPLATE = app

SOURCES += main.cpp \
protocolhandler.cpp

HEADERS += protocolhandler.h \
Interfaces/protocolinterface.h \
Interfaces/protocolloader.h \
    Interfaces/turnstile.h

./Plugins/Dummy/DummyPluginInterface.h

#include "protocolloader.h"
#include <QObject>
class DummyPluginInterface : public QObject, PluginInterface {
    Q_OBJECT
    Q_INTERFACES(PluginInterface)
public:
    ProtocolInterface* getInterface();
    int getPluginId() const;
};

./Plugins/Dummy/DummyPluginInterface.cpp

#include "DummyPluginInterface.h"
#include "DummyProtocolInterface.h"

ProtocolInterface *DummyPluginInterface::getInterface() {
    return new DummyProtocolInterface();
}

int DummyPluginInterface::getPluginId() const {
    return 1;
}

Q_EXPORT_PLUGIN2(dummyplugin, DummyPluginInterface)

./Plugins/Dummy/DummyProtocolInterface.h

#include "protocolinterface.h"
#include <QObject>

class DummyProtocolInterface : public ProtocolInterface {
public:
    void init();
    QWidget* getConfigureGUI();
    void start();
    int getPluginId() { return 1; }
};

./Plugins/Dummy/DummyProtocolInterface.cpp

#include "DummyProtocolInterface.h"

QWidget* DummyProtocolInterface::getConfigureGUI() {
    return 0;
}

void DummyProtocolInterface::start() {
}

void DummyProtocolInterface::init() {
    emit someSignal(); /// !!! this is important for me
}

./Plugins/Dummy/Dummy.pro

TEMPLATE        = lib
CONFIG         += plugin
QT             += network
INCLUDEPATH += ../../Daemon/Interfaces/
HEADERS        += ****
SOURCES        += ****
TARGET          = *****
DESTDIR         = *****

我的问题是我收到链接错误或运行时未解析的符号（主要是来自 QObject 的一些想法）或者我的信号无法通过连接... ProtocolHandler 应该是连接信号/插槽的那个..

谁能告诉我如何使这种方法正确吗？ Qt 的例子没有涵盖这样的想法..

谢谢！

亚当

Answer 1

因此，将 ProtocolInterface.h 添加到 Plugin.pro 文件的 HEADERS += 部分解决了问题:)