问如何在Qt中正确添加类(.cpp和.h文件)

EN

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)

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

    # 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