How to Pars JSON in iOS - Objective C

JSON Pars

Objective

This is a quick guide on JSON Parse in iOS. A simple example described how to parse JSON and store JSON data in array or dictionary for further use.

Introduction:

JSON stands for JavaScript Object Notation. It is data interchange format that can be easily read and write by human and can be easily parse by machine. Given steps are very simple and it explain in simple manner with suitable code, to understand parse JSON in iOS we need to follows given steps.

Step 1 Create XCode Project

Create new XCode project name it as JSONParsingDemo. It contains one UIViewController in Main.storyboard file. The UIViewController class provides the fundamental view-management model for all iOS apps.

Step 2 Parse JSON File

The given code describe how to convert json file into NSData. Then pass that data object in NSJSONSerialization method JSONObjectWithData:options:error. That will return array or dictionary as per JSON format.

The NSJSONSerialization class to convert JSON to Foundation objects and convert Foundation objects to JSON.

-(void)parseJSONFile
{
       NSData *data = [NSData dataWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"Displaydata" ofType:@"json"]]; 

       NSDictionary *dictTemp = [NSJSONSerialization JSONObjectWithData:data options:0 error:nil];
      NSArray *arrColors = [dictTemp valueForKey:@"colorsArray"];

      for (inti=0; i< arrColors.count; i++)  { 

           Colors *colors = [[Colors alloc] init];
           [colorsparseResponse:[arrColors objectAtIndex:i]];
           [marrAllColorsaddObject:colors];
     }
  [self displayAllColros];
}

Step 3 Create Colors Model File

Create a model class that is subclass of NSObject class. That contains all the property with the keys available in JSON dictionary and write a parse JSON dictionary method and store it in class property.

In our example we have created Colors class as below.
Colors.h
#import<Foundation/Foundation.h>
@interface Colors : NSObject
@property (nonatomic,strong) NSString *colorName;
@property (nonatomic,strong) NSString *hexValue;
- (int)parseResponse:(NSDictionary *)receivedObjects;
@end

Colors.m:
#import "Colors.h"
@implementation Colors
@synthesizecolorName;
@synthesizehexValue;
- (int)parseResponse:(NSDictionary *)receivedObjects
  {
     colorName = [receivedObjects objectForKey:@"colorName"];
     hexValue = [receivedObjects objectForKey:@"hexValue"];
     return 0;
  }
@end

Step 4 Display Colors Function

In our this example it contains array of colors with key colorsArray. Create color object and call parseResponse method and pass dictionary which contains color name and its hex value. Add color object in a mutable array.

Now you can use color object and its color name and hex value property in whole class. To describe how to access color object’s property I have print color name and hex value in displayAllColors method.

-(void)displayAllColors 

 { 

      for (int i=0; i < marrAllColors.count ; i++)  { 

          Colors *color = [marrAllColors objectAtIndex:i]; 

         NSLog(@"Color : Name = %@ hexValue = %@",color.colorName,color.hexValue); 

     } 

 } 

Step 5 Call Function from viewDidLoad

Call parseJSONFile method from viewDidLoad() which looks like.

-(void)viewDidLoad 

  { 

     [super viewDidLoad]; 

     marrAllColors = [[NSMutableArray alloc] init]; 

     [self parseJSONFile]; 

  } 

I hope you found this blog helpful while JSON Parse in iOS. 

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