我的项目没有可见错误，但是当我尝试运行时，出现以下错误

Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_ConcreteScreen", referenced from:
      objc-class-ref in ViewController.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

#import "ViewController.h"


#import "ConcreteScreen.h"
@interface ViewController ()

@end

@implementation ViewController




-(IBAction)btnContactPress:(id)sender{
   NSLog(@"Contact Screen");

    ConcreteScreen *coontact = [[ConcreteScreen alloc]init];

}

最佳答案

您混淆了ConcreteScreen和ContactScreen，编译器告诉您它不知道ConcreteScreen

https://stackoverflow.com/questions/11039014/