NSKeyedUnarchiver. Loading array of custom objects from plist

Question

I am trying to load my .plist file

Into array of my cusom objects, called Property. Here is Property.h:

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface Property : NSObject<NSCoding> {
    int price_base;
    float state;
    float infrastructure;
}

-(id)initWithCoder:(NSCoder *)decoder;
-(void)encodeWithCoder:(NSCoder *)aCoder;
@end

And Property.m:

#import "Property.h"

@implementation Property
-(void)encodeWithCoder:(NSCoder *)aCoder 
{/*No need to encode yet*/}
-(id)initWithCoder:(NSCoder *)decoder {
    if (self = [super init]) {

        price_base = [decoder decodeIntForKey:@"price_base"];
        state = [decoder decodeFloatForKey:@"state"];
        infrastructure = [decoder decodeFloatForKey:@"infrastructure"];
    }
    return self;
}
@end

The code, that executes, trying to load objects is next:

-(void)loadProperty
{
    NSString *resourcePath = [[NSBundle mainBundle] pathForResource:@"Property" ofType:@"plist"];
    NSMutableArray *propertyArray = [[NSMutableArray alloc] init];
    propertyArray = [[NSKeyedUnarchiver unarchiveObjectWithFile:resourcePath] mutableCopy];
}

There is an exception, during Runtime, that drops the next:

[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x7f99e5102cc0 2015-04-30 17:40:52.616 RealEstate[5838:2092569] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFArray objectForKey:]: unrecognized selector sent to instance 0x7f99e5102cc0'

Does anyone have any idea, what may be wrong with code? I am rather new to XCode and ObjectiveC, so help would be very appreciative!

Answer 1

You are confusing archiving with serialization.

NSString *resourcePath = 
    [[NSBundle mainBundle] pathForResource:@"Property" ofType:@"plist"];
NSMutableArray *propertyArray = [[NSMutableArray alloc] init];
propertyArray = 
    [[NSKeyedUnarchiver unarchiveObjectWithFile:resourcePath] mutableCopy];

That is not how you read a .plist file. It is not archived and you don't need an unarchiver to read it. It is an array so just read it directly into an NSArray (initWithContentsOfFile:).

In the result, everything will be immutable. If that isn't what you want, you need the NSPropertyListSerialization class to help you.

Answer 2

Yeah, seems like I've been much confused with Archiving and Serialisation. So, I've modified the code as follows:

-(void)loadProperty
{
    NSString *resourcePath = [[NSBundle mainBundle] pathForResource:@"Property" ofType:@"plist"];
    NSArray *temp = [[NSArray alloc] initWithContentsOfFile:resourcePath];
    NSMutableArray *propertyArray = [[NSMutableArray alloc] init];
    for(NSDictionary *dict in temp) {
        Property *prop = [Property alloc];
        prop.price_base = (int)[[dict valueForKey:@"price_base"] integerValue];
        prop.state = [[dict valueForKey:@"state"] floatValue];
        prop.infrastructure = [[dict valueForKey:@"infrastructure"] floatValue];

        [propertyArray addObject:prop];
    }
}

And it seems like works fine. Thanks!