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POParsing JSON value on UIPickerview xcode
 

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  1. POParsing JSON value on UIPickerview xcode
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    <p>I have a pickerview with which I would want to display values using JSON parsing. I am aware some questions on the site already tackle parsing and pickerview but mine is slightly different in regards to the structure of my json file. Here's a sample of the json file.</p> <pre><code>[ { "model":"juice", "id" : [ { "version": "version01" }, { "version": "version02" } ] }, { "model":"cream", "id" : [ { "version": "cream01" }, { "version": "cream02" } ] } ] </code></pre> <p>and my .m file</p> <pre><code>- (void)viewDidLoad { [super viewDidLoad]; NSURL * serverhost = [NSURL URLWithString:@"http://my.json"]; NSError *error; NSData * Data = [NSData dataWithContentsOfURL: serverhost]; self.modelsArray= [NSJSONSerialization JSONObjectWithData:Data options:NSJSONReadingAllowFragments error:&amp;error]; NSLog(@"%@", modelsArray); } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; } - (NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView { return 2; } - (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component { if (component == departments) return [self.modelsArray count]; return [self.versionsArray count]; } #pragma mark Picker Delegate Methods - (NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component { if (component == departments) return [[self.modelsArray objectAtIndex:row]objectForKey:@"model"]; return [[[self.versionsArray objectAtIndex:row]objectForKey:@"model"]objectForKey:@"version"]; } -(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent: (NSInteger)component { if (component == departments) { NSString * selectedRow = [[self.modelsArray objectAtIndex: row] valueForKey:@"version"]; NSArray * array = [sybreDepts objectForKey:selectedRow]; self. } } @end </code></pre> <p>Basically when I select a model i.e juice or cream on the first column the second column should display its contents with key being 'versions' thus when juice is selected "version01" and "version02" should be displayed on the second column.</p> <p>In regards to the line <code>return [[[self.versionsArray objectAtIndex:row]objectForKey:@"model"]objectForKey:@"version"];</code> I don't believe it was executed correctly as I get an error</p> <pre><code>*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString objectForKey:]: unrecognized selector sent to instance 0xa18c450' . Any suggestions ? Thanks </code></pre>
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    1. USJohn Stone
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    1. COWelcome to StackOverflow. A few comments to your question: The shown JSON is invalid; could it be that a double quote is missing after `version02`? What do you mean by "but the version names are not"? Does it crash? Doesn't it compile? Please better describe what you expect to happen and what happens actually.
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      1. USCodo
    2. COIs the line `return [[[self.versionsArray objectAtIndex:row]objectForKey:@"model"]objectForKey:@"version"];` ever called? If you retrieve the element with the key *model*, you just get a string. But your code expects to find a JSON object with a *version* key.
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      1. USCodo
    3. COHi Codo, thank you. I have corrected json file, just typographical errors. Basically when I select a model i.e juice or cream on the first column the second column should display its contents with key being 'versions' thus when juice is selected "version01" and "version02" should be displayed on the second column. In regards to the line return [[[self.versionsArray objectAtIndex:row]objectForKey:@"model"]objectForKey:@"version"];.
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      1. USJohn Stone
 

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