List of class properties in Objective-C

Question

Is there a way to get an array of class properties of certain kind? For example if i have interface like this

@interface MyClass : NSObject
    @property (st         


        

Answer 1

The answer by @user529758 won't work with ARC and it won't list the properties of any ancestor classes.

To fix this, you need to traverse up the class hierarchy, and use the ARC-compatible [NSObject valueForKey:] to get the property values.

Person.h:

#import 

extern NSMutableArray *propertyNamesOfClass(Class klass);

@interface Person : NSObject

@property (nonatomic) NSString *name;

@end

Person.m:

#import "Person.h"
#import 

NSMutableArray *propertyNamesOfClass(Class klass) {
    unsigned int count;
    objc_property_t *properties = class_copyPropertyList(klass, &count);

    NSMutableArray *rv = [NSMutableArray array];

    for (unsigned int i = 0; i < count; i++)
    {
        objc_property_t property = properties[i];
        NSString *name = [NSString stringWithUTF8String:property_getName(property)];
        [rv addObject:name];
    }

    free(properties);

    return rv;
}

@implementation Person

- (NSMutableArray *)allPropertyNames {
    NSMutableArray *classes = [NSMutableArray array];
    Class currentClass = [self class];
    while (currentClass != nil && currentClass != [NSObject class]) {
        [classes addObject:currentClass];
        currentClass = class_getSuperclass(currentClass);
    }

    NSMutableArray *names = [NSMutableArray array];
    [classes enumerateObjectsWithOptions:NSEnumerationReverse usingBlock:^(Class currentClass, NSUInteger idx, BOOL *stop) {
        [names addObjectsFromArray:propertyNamesOfClass(currentClass)];
    }];

    return names;
}

- (NSString*)description {
    NSMutableArray *keys = [self allPropertyNames];
    NSMutableDictionary *properties = [NSMutableDictionary dictionaryWithCapacity:keys.count];
    [keys enumerateObjectsUsingBlock:^(NSString *key, NSUInteger idx, BOOL *stop) {
        properties[key] = [self valueForKey:key];
    }];

    NSString *className = NSStringFromClass([self class]);
    return [NSString stringWithFormat:@"%@ : %@", className, properties];
}

Student.h:

#import "Person.h"

@interface Student : Person

@property (nonatomic) NSString *studentID;

@end

Student.m:

#import "Student.h"

@implementation Student

@end

main.m:

#import 
#import "Student.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {
        // insert code here...
        Student *student = [[Student alloc] init];
        student.name = @"John Doe";
        student.studentID = @"123456789";
        NSLog(@"student - %@", student);
    }
    return 0;
}