c++ - QFileSystemWatcher Unresolved external

Question

我正在摆弄 QFileSystemWatcher，跟随 this example .但是在编译时出现 Unresolved external symbol 错误。这是我的代码:

#include <QCoreApplication>
#include <QFileSystemWatcher>
#include <QObject>

#include <iostream>

class MyClass : public QObject
{
    Q_OBJECT

public:
    MyClass(QObject* parent = nullptr) : QObject(parent){}

public slots:
    void on_dir_change(const QString& path)
    {
        std::cout << "folder modified: (" << path.toStdString() << ")" << 
std::endl;
    }
};

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    QFileSystemWatcher watcher;
    watcher.addPath("C:/test");

    MyClass* mc = new MyClass();

    QObject::connect(&watcher, SIGNAL(directoryChanged(QString)), mc, 
SLOT(on_dir_change(QString)));

    return a.exec();
}

编译时会产生以下错误信息:

main.obj:错误 LNK2001:未解析的外部符号“public:virtual struct QMetaObject const * __cdecl MyClass::metaObject(void)const”(?metaObject@MyClass@@UEBAPEBUQMetaObject@@XZ)

main.obj:错误 LNK2001:未解析的外部符号“public:virtual void * __cdecl MyClass::qt_metacast(char const *)”(?qt_metacast@MyClass@@UEAAPEAXPEBD@Z)

main.obj:错误 LNK2001:未解析的外部符号“public: virtual int __cdecl MyClass::qt_metacall(enum QMetaObject::Call,int,void * *)”(?qt_metacall@MyClass@@UEAAHW4Call@QMetaObject @@HPEAPEAX@Z)

debug\FileSystemWatcherTest.exe: fatal error LNK1120:3 个 Unresolved external 问题

我做错了什么？

Answer 1

尝试将 MyClass 定义放在单独的 .h 文件中