iOS description方法

前言:最近在读Effective Objective-C 2.0 ,看到有讲解description方法，总结一下写出来

Pragma mark — 直接上代码，创建一个testObject类,给两个属性:name和money

#import <Foundation/Foundation.h>

@interface testObject : NSObject

/**<#注释#>*/
@property (nonatomic , copy) NSString * name;
/**<#注释#>*/
@property (nonatomic , copy) NSString * money;

-(instancetype)initWithName:(NSString *)name money:(NSString *)money;

@end

#import "testObject.h"

@implementation testObject

-(instancetype)initWithName:(NSString *)name money:(NSString *)money{
      self = [super init];
    if (self) {
        _name = name;
        _money = money;
    }
    
    return self;
}

Pragma mark — NO.2 重写方法之前看打印效果和arr打印对比

- (void)viewDidLoad {
    [super viewDidLoad];

    
    //数组
    NSArray *arr = @[@"name",@"type"];
    NSLog(@"arr = %@",arr);
    
    //自己的类
    testObject *test1 = [[testObject alloc]initWithName:@"jiangjun" money:@"100"];
    NSLog(@"test1 = %@",test1);
}

#打印结果
 arr = (
    name,
    type
)
 test1 = <testObject: 0x608000023f20>

从上可以看出对于arr来说打印了详细信息，而我们自己的类只打印了类型名和地址。

Pragma mark — NO.3 重写方法后，打印结果查看

//重写description方法---最简单的打印
- (NSString *)description{
  //我们重写时，还是要打印那个类名，地址，这样会更加清晰
    return [NSString stringWithFormat:@"%@ : %p, %@,%@",[self class],self,_name,_money];
   
}

//打印结果
arr = (
    name,
    type
)
 test1 = testObject : 0x60000003fde0, jiangjun,100

#重写一个更清晰的打印效果
//封装为字典的打印
-(NSString *)description{
     return  [NSString stringWithFormat:@"%@ : %p , %@",[self class],self,@{@"name":_name,@"money":_money}];
    
}

//打印结果—更加一目了然
test1 = testObject : 0x600000030e20 , {
    money = 100;
    name = jiangjun;
}