Question

我创建了一些示例来学习objective-c中的一些基础知识。我有一个名为Person的类，如下所示。在主要方法中，我尝试调用description方法来打印一些数据，而AFAIK，description method与java toString类似，我创建的description方法不是称为

请查看下面的代码，让我知道为什么不调用description方法的内容。

person.h

#import <Foundation/Foundation.h>

@interface Person : NSObject {
    int age;
    int weight;
}

-(void) setAge:(int) age;
-(void) setWeight: (int) weight;

-(int) getAge;
-(int) getWeight;

-(NSString *) description;

@end

person.m

#import "Person.h"

@implementation Person

-(void) setAge:(int) a {
    age = a;
}

-(void) setWeight:(int) w {
    weight  = w;
}

-(int) getAge {
    return age;
}

-(int) getWeight {
    return weight;
}

-(NSString *) description {
    NSString *desc = @("my age is: %i and my weight is: %i", age, weight);
    NSLog(@"%@", desc);
    return desc;
}
@end

主要：

#import <UIKit/UIKit.h>
#import "AppDelegate.h"
#import "Person.h"

int main(int argc, char * argv[]) {
    @autoreleasepool {

        Person *me = [[Person alloc] init];

        [me setAge:20];
        [me setWeight:55];

        NSString *desc = [me description];
        NSLog(@"%@", desc);

        return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
    }
}

Answer 1

您可能会调用description方法，但是您没有收到日志消息。问题在于您生成的NSString。这是无效的：

NSString *desc = @("my age is: %i and my weight is: %i", age, weight);

尝试将其更改为：

NSString *desc = [NSString stringWithFormat:@"my age is: %i and my weight is: %i", age, weight];

描述方法未被调用

1 个答案: