将函数指针插入QMap(Qt) [英] Insert function pointer into QMap (Qt)

问题描述

我正在Qt中为REST API创建一种路由器，并且在将函数指针插入QMap时遇到了问题.

I am creating sort of a router for REST API in Qt and I am facing problem with inserting the function pointer into the QMap.

我有一个IModule类，从中派生了其他模块. IModule.h的重要行是

I have class IModule from which the other modules are derivated. Important lines of IModule.h are

typedef QByteArray* (*IBusAction)(IBus * , ProxyRequest *);

class IModule : public QObject
{
   Q_OBJECT

  protected:
    QMap<QString , IBusAction > *m_actions;

然后我有一个UserModule，它是从IModule派生的，在.cpp文件中，我有以下几行:

Then I have UserModule which is derived from IModule and in .cpp file I have these lines:

QByteArray* UserModule::create(IBus *bus, ProxyRequest *req)
{
}

QByteArray* UserModule::show( IBus *bus, ProxyRequest *req)
{
}


UserModule::UserModule(QObject *parent) :
IModule(parent)
{

    // register functions
    m_actions->insert("show", &UserModule::show);
    m_actions->insert("create", UserModule::create);

}

因此，我尝试了两个选项，如何在没有引用的情况下将具有引用符号的函数放入QMap中，但两者均无法正常工作.我收到错误消息:no matching function for call to 'QMap<QString, QByteArray* (*)(IBus*, ProxyRequest*)>::insert(const char [5], QByteArray* (UserModule::*)(IBus*, ProxyRequest*))'

So I tried two options how to put the function in QMap with referencing sign also without it, but both are not working. I am getting error: no matching function for call to 'QMap<QString, QByteArray* (*)(IBus*, ProxyRequest*)>::insert(const char [5], QByteArray* (UserModule::*)(IBus*, ProxyRequest*))'

我花了几个小时解决这个问题，尝试了许多不同的方法来解决它，但是没有成功.

I have spent several hours with this problem, tried many different things how to solve it but there was no success.

因此，我将很高兴为您提供任何建议.

So I will be very glad for any piece of advice.

推荐答案

您的IBusAction是指向函数的指针类型.这与指向成员的指针功能不兼容.

Your IBusAction is a pointer-to-function type. This is not compatible with pointer-to-member function.

当调用成员函数(如UserModule::create函数)时，它需要一个额外的(不可见")参数:调用该函数的实例(this指针).

When you call a member function (like your UserModule::create function), it needs an extra ("invisible") parameter: the instance the function gets called on (the this pointer).

您基本上有三个选择:

• 将IBusAction更改为UserModule成员函数的指针.但是，您只能使用该类的功能.

• Change IBusAction to be a pointer-to-member-function-of-UserModule. You're restricted to that class's functions with this though.

typedef QByteArray* (UserModule::*IBusAction)(IBus * , ProxyRequest *);

使函数static(这将更改代码的语义)

Make the functions static (this changes the semantics of your code)

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