如何实现宏SIGNAL和SLOT作为函数QT [英] how to implement the macros SIGNAL and SLOT as functions QT

问题描述

嗯，我想要的是实现类似于SIGNAL和SLOT宏的函数，但是使用我自己的实现，所以目标是函数（或我自己的宏，如果我可以创建它）接收一个参数像String mycustomsignal和他返回一个const char *2mycustomsignal（double，int）所以我这样做使用QMap存储这个asociation QMap<信号名称，信号签名>，我填写另一个函数。 / p>

在这种情况下，我的QMap是 this-> signals 所以我搜索签名mycustomsignal键mycustomsignal和前面的代码，QObject :: connect识别的信号，我得到2mycustomsignal（something）所以我转换它在const char *因为QObject :: connect有这个参数的格式，我想使用也与SIGNAL和SLOT MACROS结合，如下：

  QObject :: connect（customwidget，customwidget-> getSignal ），
 somewidget，SLOT（someslot（）））; 
  

我使用的函数是（仅对于我和我做什么）：

  const char * SomeClass :: getSignal（QString signalName）{
 QString signalsignature = this-> signals.value（signalName）; 
 signalsignature.prepend（QString :: number（QSIGNAL_CODE））; 
 QByteArray ba = signalsignature.toLatin1（）; 
 return signalformated; //这里是丢失的数据，因为QByteArray只存在于函数
} 
  

这个返回一个指向本地的指针，当函数结束时，数据的源被销毁，那么我怎么能用一个函数或创建我自己的MACRO呢？

谢谢

解决方案

您必须从您的方法中返回QByteArray， return ba; ，然后从返回值获取 const char * ：

 code> QObject :: connect（customwidget，customwidget-> getSignal（somesignal）。constData（），
 somewidget，SLOT（someslot（）））; 
  

如果你真的想返回char指针，那么你必须保持QByteArray将它添加到同一对象的QList成员变量中，因此当实例被销毁时，它将被销毁。

Well, what i want is to implement functions that works like the macros SIGNAL and SLOT but with my own implementation, so the goal is that the function (or my own macro if i can create it) receive a parameter like an String "mycustomsignal" and he return a const char* "2mycustomsignal(double,int)" so i do that using a QMap for store this asociation QMap<"signal name","signal signature">, i fill it in another function.

in this case my QMap is this->signals so i search the signature "mycustomsignal(something)" with the key "mycustomsignal" and prepend the code that QObject::connect recognize for signals and i get "2mycustomsignal(something)" so i convert it in const char* because QObject::connect have this parameters in this format and i want to use also in conjuntion with SIGNAL and SLOT MACROS like this:

QObject::connect(customwidget, customwidget->getSignal("somesignal"), 
                 somewidget, SLOT(someslot()));

the function that i use is (only for undertand what i do):

const char* SomeClass::getSignal(QString signalName) {
    QString signalsignature = this->signals.value(signalName); 
    signalsignature.prepend(QString::number(QSIGNAL_CODE)); 
    QByteArray ba = signalsignature.toLatin1();
    return signalformated; //Here is the lost of data because QByteArray only exist in the function
}

but this return a pointer to local and the source of the data is destroyed when the function ends, so how i could do this with a function or creating my own MACRO?

Thanks for any help or suggestion.

解决方案

You have to return QByteArray from your method, return ba;, then get the const char* from the return value:

QObject::connect(customwidget, customwidget->getSignal("somesignal").constData(),
                 somewidget, SLOT(someslot()));

If you really want to return char pointer, then you have to keep the QByteArray around, for example by adding it to a QList member variable of the same object, so it will get destructed when the instance gets destructed.

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