这是我尝试编译时 XCode 的输出。我已经彻底检查了我的头文件，以确认我没有包含两次。有没有人看到还有什么可能导致这个问题？我什至删除了项目并重新生成了它。我不知道我做了什么才能让这一切发生。提前致谢！
Ld Debug-iphonesimulator/Timecards.app/Timecards normal i386
cd /Users/allenh1/time-flashcards-ios/timecards-ios
setenv IPHONEOS_DEPLOYMENT_TARGET 4.3
setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin"
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch i386 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.1.sdk -L/Users/allenh1/time-flashcards-ios/timecards-ios/Debug-iphonesimulator -L/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs/iPhoneSimulator6.1.sdk/System/Library/Frameworks -L/Users/allenh1/Qt/5.1.0/Src/qtbase/lib -L/Users/allenh1/Qt/5.1.0/Src/qtbase/plugins/platforms -F/Users/allenh1/time-flashcards-ios/timecards-ios/Debug-iphonesimulator -filelist /Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/Timecards.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -headerpad_max_install_names -framework UIKit -lz -force_load /Users/allenh1/Qt/5.1.0/Src/qtbase/plugins/platforms/libqios.a -framework UIKit -L/Users/allenh1/Qt/5.1.0/Src/qtbase/lib -framework OpenGLES -L/Users/allenh1/Qt/5.1.0/Src/qtbase/plugins/platforms -lz -lm -Xlinker -no_implicit_dylibs -mios-simulator-version-min=4.3 -framework Foundation -framework QuartzCore -lQt5PlatformSupport -framework CoreFoundation -framework CoreText -framework CoreGraphics -lqiosmain -lQt5Widgets -lQt5Gui -lQt5Core -o /Users/allenh1/time-flashcards-ios/timecards-ios/Debug-iphonesimulator/Timecards.app/Timecards
duplicate symbol __ZplRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/mainwindow.o
duplicate symbol __ZmiRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/mainwindow.o
duplicate symbol __ZplRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/TimeQuestion.o
duplicate symbol __ZmiRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/TimeQuestion.o
duplicate symbol __ZplRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/TimecardTime.o
duplicate symbol __ZmiRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/TimecardTime.o
duplicate symbol __ZplRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/moc_mainwindow.o
duplicate symbol __ZmiRK12TimecardTimeS1_ in:
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/main.o
/Users/allenh1/time-flashcards-ios/timecards-ios/Timecards.build/Debug-iphonesimulator/Timecards.build/Objects-normal/i386/moc_mainwindow.o
ld: 8 duplicate symbols for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)