Converting an NSString of JSON Data to NSArray [closed]

Question

I have an NSString that is storing a JSON array in the form of a NSString. The NSString called colorArray has the value of:

[{ "color":"Red" },{ "color":"Blue" },{ "color":"Yellow"}];

I also have a tableview that I would like to import the array into in order to populate the table. The table works if I load the tableData into an array like below, but I can't figure out how to convert the NSString into an array that can be used to populate the tableData like shown below...

Anyone have ideas? Thanks much!

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Initialize table data
    tableData = [NSArray arrayWithObjects:@"Red", @"Blue", @"Yellow", nil];
}

Answer 1

// Your JSON data:
NSString *colorArray = @"[{ \"color\":\"Red\" },{ \"color\":\"Blue\" },{ \"color\":\"Yellow\"}]";
NSLog(@"colorArray=%@", colorArray);

// Convert to JSON object:
NSArray *jsonObject = [NSJSONSerialization JSONObjectWithData:[colorArray dataUsingEncoding:NSUTF8StringEncoding]
                                                      options:0 error:NULL];
NSLog(@"jsonObject=%@", jsonObject);

// Extract "color" values:
NSArray *tableData = [jsonObject valueForKey:@"color"];
NSLog(@"tableData=%@", tableData);

Output:

colorArray=[{ "color":"Red" },{ "color":"Blue" },{ "color":"Yellow"}]
jsonObject=(
        {
        color = Red;
    },
        {
        color = Blue;
    },
        {
        color = Yellow;
    }
)
tableData=(
    Red,
    Blue,
    Yellow
)

The last step uses the special feature of -[NSArray valueForKey:] that returns an array containing the results of invoking valueForKey: using the key on each of the array's objects.

Answer 2

Try

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSString *jsonString = ...//String representation of json 
    NSData *jsonData =  [jsonString dataUsingEncoding:NSUTF8StringEncoding];
    //colors is a NSArray property used as dataSource of TableView
    self.colors = [NSJSONSerialization JSONObjectWithData:jsonData
                                                  options:NSJSONReadingMutableContainers
                                                    error:nil];

}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    // Return the number of sections.
    return 1;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.
    return [self.colors count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    NSDictionary *color = self.colors[indexPath.row];
    cell.textLabel.text = color[@"color"];

    return cell;
}