如何在Qt中正确添加类（.cpp和.h文件）

Question

So I've written some classes in Visual Studio(they worked in VS) and I added them to Qt. When I Make a pointer to a class, everything's okay. If I make the class, however, I get 2 "unresolved external symbol" errors about 2 methods(there are only 2 in class). One of them looks like this:

mainwindow.obj:-1: error: LNK2001: unresolved external symbol "protected: virtual void __cdecl SRT::processInputLine(class Subtitles &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?processInputLine@SRT@@MEAAXAEAVSubtitles@@AEBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z)

Here's the declaration of this method:

virtual void processInputLine(Subtitles& subtitles, const string& line) throw(TimesOverlap) override;

Class Subtitles inherits vector, where Subtitle is another class.

If I paste the definitions into this file(which I know I shouldn't do) I only get the same errors for other classes that these methods use, but not the previous 2 errors. Is Qt not linking .cpp files correctly? Why does this linking error occur only if I create class, and not before? Any ideas? Thanks!

Edit1: Here's my .pro file:

    # deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += main.cpp\
    mainwindow.cpp \
    Subtitles.cpp \
    MicroDVD.cpp \
    MPlayer.cpp \
    Subtitle.cpp \
    TimeStamp.cpp \
    SRT.cpp \
    SubtitleIO.cpp

HEADERS  += mainwindow.h \
    globalVariables.h \
    Exceptions.h \
    MicroDVD.h \
    MPlayer.h \
    Subtitle.h \
    Subtitles.h \
    TimeStamp.h \
    SRT.h \
    SubtitleIO.h

FORMS    += mainwindow.ui

DISTFILES += \
    SubtitleEditor.pro.user

As you can see .h and .c files are included. I'm trying to figure out how to run qmake...

Answer 1

You should add them to your pro file like:

HEADERS += yourClass.h
SOURCES += yourClass.cpp

run qmake and it should compile fine.

Click Build -> Run qmake

Quick explanation: qmake creates makefiles for your project. Therefore whenever you add classes you should run it to assure that everything gets updated.

Answer 2

I'm trying to figure out how to run qmake...

Use qmake.exe yourProFile.pro on the console. Alternatively all IDE provide a way to run qmake. If you are using Qt Creator call Build > Run qmake .