Update JSON data in tableview properly - objective-c

Question

Iam having a hard time updating my tableview with new results when the user slides to update (UIRefreshControl). The controller works properly, but the data never gets updated. I've tried to wipe the raw-data variable, and my NSArray that holds all the data, but it doesn't seem to work. Iam new to iPhone programming, so forgive me is this is a dumb question.
If I managed to fixed it, wouldn't it be wrong to remove all the data I've already pulled? Is there a simple way to append changes, considering most of my users will be using 3G/Edge connections. Here's my implementation class for the TableViewController:
#import "Nyhetsfane.h"
#interface Nyhetsfane ()
#end
#implementation Nyhetsfane
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
// Uncomment the following line to preserve selection between presentations.
// self.clearsSelectionOnViewWillAppear = NO;
// Kaller på slide to update.
[self updateTable];
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init];
[refreshControl addTarget:self action:#selector(updateTable) forControlEvents:UIControlEventValueChanged];
[refreshControl setAttributedTitle:[[NSAttributedString alloc] initWithString:#"Dra for å oppdatere"]];
self.refreshControl = refreshControl;
}
- (void)updateTable{
// Viser "spinner" for å symbolisere nettverkstrafikk.
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
// URL til JSON filen
NSURL *newsUrl = [NSURL URLWithString:#"http://localhost:7192/fadderapp/events.json"];
//URL Requestobjekt for å kontrollere tilkobling
NSURLRequest *newsRequest = [NSURLRequest requestWithURL:newsUrl];
[[NSURLConnection alloc]initWithRequest:newsRequest delegate:self];
[self.tableView reloadData];
[self.refreshControl endRefreshing];
}
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
[newsRawData setLength:0];
newsRawData = [[NSMutableData alloc] init];
}
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
[newsRawData appendData:data];
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
newsCases = [NSJSONSerialization JSONObjectWithData:newsRawData options:0 error:0];
[self.tableView reloadData];
}
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error {
UIAlertView *errorView = [[UIAlertView alloc]initWithTitle:#"Feil" message:#"Det har oppstått en feil ved nedlastingen av data. Dobbeltsjekk at du er koblet til internett" delegate:nil cancelButtonTitle:#"Fortsett" otherButtonTitles:nil];
[errorView show];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return [newsCases count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if(cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"];
}
cell.textLabel.text = [[newsCases objectAtIndex:indexPath.row]objectForKey:#"navn"];
return cell;
}
...
For all it's worth, here's my JSON feed:
[
{"navn": "Registration", "tidspunkt": "Monday 15:05", "beskrivelse": "Demo!"},
{"navn": "Party!", "tidspunkt": "Monday 19:30", "beskrivelse": "Demo"}
]

Answer 1

Try with this code
- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
newCases = [NSArray array];
newsCases = [NSJSONSerialization JSONObjectWithData:newsRawData options:0 error:0];
[self.tableView reloadData];
}

Answer 2

The proper way to update a table view is to call
[self.tableView reloadData];
It should call all its datasource methods again automatically.