objective-c - 运行奇怪的错误运行 objective-c 代码

Question

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)

我在ViewController.m中使用ContactScreen类

我尝试通过@class ContactScree和#import "ContactScreen.h"
在我的ViewController中，我将其用作 [ContactScreen myMethod];当我注释掉这一行时，它工作正常，但现在却给出了编译时错误:(
昨天天气很好

这是我的代码

#import "ViewController.h"


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

@end

@implementation ViewController




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

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

}

Answer 1

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