(XCode-iOS) Undefined symbols for architecture x86_64

Hi everyone!

I'm new on iOS, and I'm having trouble to make a label through code.

Sadly im getting this error:

Ld /Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifohjo ncscfqgzsoqfrtyduzkn/Build/Products/Debug-iphonesimulator/Geometria.app/Geometri a normal x86_64

cd /Users/viniciusterranova/Praticando/Geometria

setenv IPHONEOS_DEPLOYMENT_TARGET 7.0

setenv PATH "/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/ Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/b in:/usr/sbin:/sbin"

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/ usr/bin/clang -arch x86_64 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/D eveloper/SDKs/iPhoneSimulator7.0.sdk -L/Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifoh joncscfqgzsoqfrtyduzkn/Build/Products/Debug-iphonesimulator -F/Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifoh joncscfqgzsoqfrtyduzkn/Build/Products/Debug-iphonesimulator -filelist /Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifohjo ncscfqgzsoqfrtyduzkn/Build/Intermediates/Geometria.build/Debug-iphonesimulator/G eometria.build/Objects-normal/x86_64/Geometria.LinkFileList -Xlinker -objc_abi_version -Xlinker 2 -fobjc-arc -fobjc-link-runtime -Xlinker -no_implicit_dylibs -mios-simulator-version-min=7.0 -framework CoreGraphics -framework UIKit -framework Foundation -Xlinker -dependency_info -Xlinker /Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifohjo ncscfqgzsoqfrtyduzkn/Build/Intermediates/Geometria.build/Debug-iphonesimulator/G eometria.build/Objects-normal/x86_64/Geometria_dependency_info.dat -o /Users/viniciusterranova/Library/Developer/Xcode/DerivedData/Geometria-bwifohjo ncscfqgzsoqfrtyduzkn/Build/Products/Debug-iphonesimulator/Geometria.app/Geometri a

Undefined symbols for architecture x86_64:

"_OBJC_IVAR_$_UIViewController._view", referenced from:

-[ViewController viewDidLoad] in ViewController.o

ld: symbol(s) not found for architecture x86_64

clang: error: linker command failed with exit code 1 (use -v to see invocation)

Here is my ".m" file Code:

#import "ViewController.h"

@interfaceViewController ()

@end

@implementation ViewController

- (void)viewDidLoad

{

[superviewDidLoad];

//criação de label via código

UILabel* labelMensagem = [[UILabel alloc]initWithFrame:CGRectMake(0.0, 0.0, 200.0, 30.0)];

labelMensagem.backgroundColor = [UIColor orangeColor];

labelMensagem.text = @"Quaddro Treinamentos";

labelMensagem.textAlignment = NSTextAlignmentCenter;

[_view addSubview:labelMensagem];

}

- (void)didReceiveMemoryWarning

{

[superdidReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

@end