Converting an NSString of JSON Data to NSArray [closed] - ios

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Closed 9 years ago.
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;
}

Answer 3

NSData * data = [colorArray dataUsingEncoding:NSUTF8StringEncoding]
NSDictionary *JSON =
[NSJSONSerialization JSONObjectWithData: data
options: NSJSONReadingMutableContainers
error: &e];
NSArray *tableData = [JSON valueForKey:#"color"];
Hope this helps..

Answer 4

Assuming you are using ios 5 or higher, JSON serialization is built in:
NSArray *json = [NSJSONSerialization
JSONObjectWithData:[string dataUsingEncoding:NSUTF8StringEncoding]
options:kNilOptions
error:&error];
Prior to ios5, you can use SBJSON to achieve the same:
NSArray *jsonObjects = [jsonParser objectWithString:string error:&error];

Answer 5

You just need to parse your tring in this way :
NSString *jsonString = #"[{\"color\":\"Red\" },{\"color\":\"Blue\" },{\"color\":\"Yellow\"}]";
NSData *jsonData = [jsonString dataUsingEncoding:NSUTF8StringEncoding];
NSError *error = nil;
NSArray *jsonArray = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];
after this you have an array of dictionay to get all the values you have to do loop the array and read each dictionary
NSMutableArray *colorsArray = [NSMutableArray arrayWithCapacity:[jsonArray count]];
for (NSDictionary *colorDictionary in jsonArray) {
NSString *colorString = [colorDictionary objectForKey:#"color"];
[colorsArray addObject:colorString];
}
Now colorsArray is NSMutableArray like this :
[NSMutableArray arrayWithObjects:#"Red", #"Blue", #"Yellow", nil];

Answer 6

If your data in coming from a webservice:
NSArray *tableData = [[NSJSONSerialization JSONObjectWithData:request.responseData options: NSJSONReadingMutableContainers error: &error] objectForKey:"yourKeyForColorArray"];