Question

如何在Objective-C中创建全局函数问题，怎么解决

若以下回答无法解决问题，邀请你更新回答

Answer 1

Two options here. First is create a class method in a static class:

Header:
#import <Foundation/Foundation.h>

@interface GlobalStuff : NSObject {}

+ (void)printTest;

@end

Implementation:
#import "functions.h"

@implementation GlobalStuff

+ (void) printTest {
NSLog(@"test");
}

Call using:
#import "functions.h"

...
[GlobalStuff printTest];

The other option is to declare a global function instead of class:

Header:
void GSPrintTest();

Implementation:
#import <Foundation/Foundation.h>
#import "functions.h"
void GSPrintTest() {
NSLog(@"test");
}

Call using:
#import "functions.h"
...
GSPrintTest();

A third (bad, but possible) option would be adding a category to NSObject for your methods:

Header:
#import <Foundation/Foundation.h>

@interface NSObject(GlobalStuff)
- (void) printTest;
@end

Implementation:
#import "functions.h"

@implementation NSObject(GlobalStuff)
- (void) printTest {
NSLog(@"test");
}
@end

Call using:
#import "functions.h"
...
[self printTest];