JSONModel - Using & Implementing KeyMapper

Question

I am using JSONModel for a basic app that returns a JSON object.

Here is a sample of the data I am returning: https://gist.github.com/ryancoughlin/8043604 - Focusing on the tide object.

I am trying to work in JSONModel JSONKeyMapper - docs here (scroll down towards the middle) - https://github.com/icanzilb/JSONModel/blob/master/README.md#magical-data-modelling-framework-for-json

I am trying to find out how to implement it. I understand that it takes a key path similar too:

---

EDIT: From my breakpoint: http://dl.dropbox.com/u/19301636/Screenshots/rzqv.png

This is what json returns: http://dl.dropbox.com/u/19301636/Screenshots/y5mt.png

---

TIDEMAPPER.M

#import "TideMapper.h"

@implementation TideMapper

+(JSONKeyMapper*)keyMapper
{
    return [[JSONKeyMapper alloc] initWithDictionary:@{
                                                       @"tide.tideInfo": @"tideSite",
                                                       @"tide.tideSummaryStats": @"maxheight",
                                                       }];
}

@end

TIDEMAPPER.M

#import "TideMapper.h"

@implementation TideMapper

+(JSONKeyMapper*)keyMapper
{
    return [[JSONKeyMapper alloc] initWithDictionary:@{
                                                       @"tideSummaryStats.maxheight": @"maxheight",
                                                       @"tideSummaryStats.minheight": @"minheight",
                                                       @"tideInfo.lat": @"lat",
                                                       @"tideInfo.lon": @"lon"
                                                       }];
}

@end

VIEW

@implementation TideDetailViewController

- (void)viewDidAppear:(BOOL)animated {

    [super viewDidAppear:YES];

    NSString *locationQueryURL = @"http://api.wunderground.com/api/xxxx/tide/geolookup/q/43.5263,-70.4975.json";

    [JSONHTTPClient getJSONFromURLWithString: locationQueryURL
                                  completion:^(NSDictionary *json, JSONModelError *err) {

//                                      NSArray* results = [json valueForKeyPath:@"tide.tideInfo"];

                                      _tide = [TideMapper arrayOfDictionariesFromModels:json];
                                       NSLog(@"loans: %@", _tide);

                                  }];
}

I think I need to change tide to NSDictionary - I dont think it returns an array. Its only a single result for a location

I am stuck when it comes to calling this method. Does anyone have any experience using this JSONModel KeyMapper?

Thanks

Answer 1

You do not call this method yourself. Your model class calls it once when the class is loaded and gets your dictionary map and uses it every time you initialize a copy of your model.

Ie. when you call initWithDictionary (or initWithJSONString) your model class will map each JSON key to a class property, however for the keys you listed in your KeyMapper will do the following:

• it will take the value of tideSummaryStats.maxheight in your JSON and store it in your class model's 'maxheight' property
• it will take the value of tideSummaryStats. minheight in your JSON and store it in your class model's 'minheight' property
• etc, etc.

Again - note that your model will automatically do that for you upon init, and all other JSON keys it'll try to map to properties with their corresponding names.

If you have 10 spare minutes you can read through this tutorial, which showcases using a custom key mapper with YouTube's JSON API:

http://www.touch-code-magazine.com/how-to-make-a-youtube-app-using-mgbox-and-jsonmodel/