descprition方法
Person.h
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface Person : NSObject
@property(strong, nonatomic) NSString* name;
@end
NS_ASSUME_NONNULL_END
Person.m
重写description方法
#import "Person.h"
@implementation Person
- (NSString *)description
{
return [NSString stringWithFormat:@"name:%@", self.name];
}
@end
main.m
#import <Foundation/Foundation.h>
#import "Person.h"
int main(int argc, const char * argv[]) {
@autoreleasepool {
Person* p1 = [Person new];
p1.name = @"dancer";
//幕后调用了一个description方法
NSLog(@"p1:%@",p1);
}
return 0;
}
类型方法
Person.h
#import <Foundation/Foundation.h>
NS_ASSUME_NONNULL_BEGIN
@interface Person : NSObject
-(instancetype)initWithName:(NSString*)name;
+(instancetype)personWithName:(NSString*)name;
+(void)sayHello;
@end
NS_ASSUME_NONNULL_END
Person.m
#import "Person.h"
@interface Person()
@property(strong, nonatomic)NSString* name;
@end
@implementation Person
- (instancetype)initWithName:(NSString *)name{
self = [super init];
if(self){
_name = name;
}
return self;
}
+ (instancetype)personWithName:(NSString *)name{
Person* p = [[Person alloc]initWithName:name];
return p;
}
+ (void)sayHello{
//类方法里不能访问成员变量
//_name = @"dancer";
//如果一个方法的实现逻辑,并不关注细节的不同,可以设计成类型方法
NSLog(@"Hello world");
}
@end
main.m
#import <Foundation/Foundation.h>
#import "Person.h"
int main(int argc, const char * argv[]) {
@autoreleasepool {
Person* p1 = [Person personWithName:@"dancer"];
//反馈结果都相同,可以使用类型方法
[Person sayHello];
}
return 0;
}