table view not showing - objective-c

Question

I'm working on this app, but somehow, its not returning any rows in my tableviewcontroller.
here is my code:
#define kBgQueue dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0)
#define kStudentenURL [NSURL URLWithString:#"http://localhost/api/api.php"]
#import "MasterViewController.h"
#import "DetailViewController.h"
#interface MasterViewController () {
NSArray *_studenten; } #end
#implementation MasterViewController
- (void)awakeFromNib {
[super awakeFromNib]; }
- (void)viewDidLoad {
[super viewDidLoad]; // Do any additional setup after loading the view, typically from a nib.
// The hud will dispable all input on the view (use the higest view possible in the view hierarchy) HUD = [[MBProgressHUD alloc] initWithView:self.navigationController.view]; [self.navigationController.view addSubview:HUD]; // Regiser for HUD callbacks so we can remove it from the window at the right time HUD.delegate = self; // Show the HUD while the provided method executes in a new thread [HUD showWhileExecuting:#selector(getJsonDataFromServer) onTarget:self withObject:nil animated:YES]; }
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated. }
-(void)getJsonDataFromServer {
dispatch_async(kBgQueue, ^{
NSData* data = [NSData dataWithContentsOfURL:
kStudentenURL];
[self performSelectorOnMainThread:#selector(fetchedData:)
withObject:data waitUntilDone:YES];
}); }
- (void)fetchedData:(NSData *)responseData {
NSError* error;
NSDictionary *json = [NSJSONSerialization
JSONObjectWithData:responseData
options:kNilOptions
error:&error];
_studenten = [json objectForKey:#"studenten"];
NSLog(#"Studenten: %#", _studenten);
NSLog(#"%u", _studenten.count); }
#pragma mark - Table View
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1; }
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return _studenten.count; }
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
NSDictionary *student = [_studenten objectAtIndex:0];
NSString *studentNaam = [student objectForKey:#"studentNaam"];
NSString *studentAchterNaam = [student objectForKey:#"studentAchterNaam"];
cell.textLabel.text = studentAchterNaam;
cell.detailTextLabel.text = studentNaam;
return cell; }
/* // Override to support rearranging the table view.
- (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { }
*/
/* // Override to support conditional rearranging of the table view.
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath {
// Return NO if you do not want the item to be re-orderable.
return YES; }
*/
/*- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
if ([[segue identifier] isEqualToString:#"showDetail"]) {
NSIndexPath *indexPath = [self.tableView indexPathForSelectedRow];
NSDate *object = _objects[indexPath.row];
[[segue destinationViewController] setDetailItem:object];
} }*/
#end
I know my json is comming in correctly. the NSLogs are returning the data i ask, but i cant seem to get any rows. Can someone give me a hand? tnx

Answer 1

Simple answer -- you need to call [(your tableview) reloadData] once you've finished loading that data array!
Presumably you've got your tableview on the storyboard right now, and you've set it's datasource and delegate to your view controller. You will also need to have a property in your view controller to that tableview. You might have some code that looks like this.
#interface MasterViewController () {
NSArray *_studenten;
}
#property (weak, nonatomic) IBOutlet UITableView *tableView;
#end
#implementation MasterViewController
- (void)fetchedData:(NSData *)responseData {
NSError* error;
NSDictionary *json = [NSJSONSerialization
JSONObjectWithData:responseData
options:kNilOptions
error:&error];
_studenten = [json objectForKey:#"studenten"];
NSLog(#"Studenten: %#", _studenten);
NSLog(#"%u", _studenten.count);
[self.tableView reloadData];
}
#end

Answer 2

My guess is that you are never getting a valid cell returned from dequeueReusableCell. What I recommend doing is after you try to reuse a cell, check to see if it is nil, if so you need to alloc a new cell. I've added the code to your function.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
if(!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"Cell"];
}
NSDictionary *student = [_studenten objectAtIndex:0];
NSString *studentNaam = [student objectForKey:#"studentNaam"];
NSString *studentAchterNaam = [student objectForKey:#"studentAchterNaam"];
cell.textLabel.text = studentAchterNaam;
cell.detailTextLabel.text = studentNaam;
return cell; }