UITableView reload data takes forever - objective-c

Question

I parse a couple of things via JSON into a table view but I have the problem that the parsing takes about a second (I know this due to the network indicator) but then there is a huge delay until the data appears in the table view.
I tried to place [tableView reloadData]; at a couple of places already but no success.
Here is my code.
I have defined mainThreadQueue and myClassicoAPI as a macro.
- (void)viewDidLoad
{
[super viewDidLoad];
arrayNeuheiten = [[NSArray alloc] init];
arrayArtikelName = [[NSArray alloc] init];
dictionaryNewStuff = [[NSDictionary alloc] init];
[self parseJSONWithURL:myClassicoAPI];
//[self performSelector:#selector(updateTableView) withObject:nil afterDelay:NO];
[neuheietenTable reloadData];
}
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[neuheietenTable reloadData];
}
-(void) updateTableView {
[neuheietenTable reloadData];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(NSInteger)numberOfRowsInSection:(NSInteger)section {
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
//return (self.arrayNeuheiten.count<17)?self.arrayNeuheiten.count : 17;
return MIN(18, arrayNeuheiten.count);
}
-(void) parseJSONWithURL: (NSURL *) jsonURL {
dispatch_async(mainThreadQueue, ^{
NSError *error = nil;
[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
NSString *json =[NSString stringWithContentsOfURL:jsonURL encoding:NSJSONWritingPrettyPrinted error:&error];
if (error == nil) {
NSData *jsonData = [json dataUsingEncoding:NSJSONWritingPrettyPrinted];
dictionaryNewStuff = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];
if (error == nil) {
dispatch_async(mainThreadQueue, ^{
arrayArtikelName = [[dictionaryNewStuff valueForKey:#"newstuff"] valueForKey:#"Neuheiten"];
arrayNeuheiten = [[dictionaryNewStuff valueForKey:#"newstuff"] valueForKey:#"Neuheiten"];
[neuheietenTable reloadData];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
});
} else {
nil;
}
} else {
nil;
}
});
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"NeuheitenCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = [[arrayArtikelName objectAtIndex:indexPath.row] objectForKey:#"name"];
return cell;
}
Thanks in advance
Constantin

Answer 1

You're loading the data synchronous on the mainthread which is bad and blocking the interface.
Try loading your JSON data with NSURLConnection and reload your UITableView in the
(void)connectionDidFinishLoading:(NSURLConnection *)aConnection
method when you're done processing it.

Answer 2

Hello I am bit modify the code with one public url and its work fine. Look at the code which useful to solve your problem:
- (void)viewDidLoad
{
[super viewDidLoad];
arrayNeuheiten = [[NSArray alloc] init];
arrayArtikelName = [[NSArray alloc] init];
dictionaryNewStuff = [[NSDictionary alloc] init];
[neuheietenTable reloadData];
NSURL *url = [NSURL URLWithString:#"http://122.182.14.104:3004/build/product/15.json"];
[self parseJSONWithURL:url];
//[self performSelector:#selector(updateTableView) withObject:nil afterDelay:NO];
}
-(void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(NSInteger)numberOfRowsInSection:(NSInteger)section {
return 1;
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
//return (self.arrayNeuheiten.count<17)?self.arrayNeuheiten.count : 17;
return arrayArtikelName.count;
}
-(void) parseJSONWithURL: (NSURL *) jsonURL {
NSError *error = nil;
NSString *json =[NSString stringWithContentsOfURL:jsonURL encoding:NSJSONWritingPrettyPrinted error:&error];
if (error == nil) {
NSData *jsonData = [json dataUsingEncoding:NSJSONWritingPrettyPrinted];
dictionaryNewStuff = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error];
if (error == nil) {
arrayArtikelName = [dictionaryNewStuff valueForKey:#"attributes"];
// arrayNeuheiten = [[dictionaryNewStuff valueForKey:#"newstuff"] valueForKey:#"Neuheiten"];
[neuheietenTable reloadData];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
} else {
nil;
}
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"NeuheitenCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = [[arrayArtikelName objectAtIndex:indexPath.row] objectForKey:#"name"];
return cell;
}