remove table rows before reload - ios

Question

I want to remove all rows in my table view before reloading the data, but can't seem to get it to work.
In my viewcontroller I get my array from this AFNetworking request.
- (void)viewDidLoad
[[LocationApiClient sharedInstance] getPath:#"locations.json"
parameters:nil
success:
^(AFHTTPRequestOperation *operation, id response) {
NSLog(#"Response: %#", response);
NSMutableArray *location_results = [NSMutableArray array];
for (id locationDictionary in response) {
Location *location = [[Location alloc] initWithDictionary:locationDictionary];
[location_results addObject:location];
}
self.location_results = location_results;
[self.tableView reloadData];
}
failure:
^(AFHTTPRequestOperation *operation, NSError *error) {
NSLog(#"Error fetching locations!");
NSLog(#"%#", error);
}];
}
And I want to remove data then reload it with this button
- (IBAction)locationPressed:(id)sender {
[[Location sharedSingleton].locationManager startUpdatingLocation];
[self viewDidLoad];
NSMutableArray *location_results = [NSMutableArray array];
[location_results removeAllObjects];
[self.tableView reloadData];
}
But it's not removing the rows. I see the reload happening over the top of the rows that are already there. Any suggestions?

Answer 1

Please DON'T EVER call viewDidLoad manually.
Create a method like
- (void)reloadDataWithCompletion:(void(^)(NSArray *locations))completion
failure:(void(^)(NSError *error))failure {
[[LocationApiClient sharedInstance] getPath:#"locations.json"
parameters:nil
success:
^(AFHTTPRequestOperation *operation, id response) {
NSLog(#"Response: %#", response);
NSMutableArray *location_results = [NSMutableArray array];
for (id locationDictionary in response) {
Location *location = [[Location alloc] initWithDictionary:locationDictionary];
[location_results addObject:location];
}
if(completion)
completion(location_results);
}
failure:
^(AFHTTPRequestOperation *operation, NSError *error) {
if(failure)
failure(error);
}];
}
And call it whenever you need to reload the data
- (void)viewDidLoad {
[super viewDidLoad]; // Don't forget the call to super!
[self reloadDataWithCompletion:^(NSArray *locations) {
self.location_results = locations;
[self.tableView reloadData];
} failure:^(NSError *error) {
NSLog(#"Error fetching locations!");
NSLog(#"%#", error);
}];
}
- (IBAction)locationPressed:(id)sender {
[[Location sharedSingleton].locationManager startUpdatingLocation];
[self reloadDataWithCompletion:^(NSArray *locations) {
self.location_results = locations;
[self.tableView reloadData];
} failure:^(NSError *error) {
NSLog(#"Error fetching locations!");
NSLog(#"%#", error);
}];
}
In order to achieve a graphical effect for reloading the table you can do (assuming that you have only one section), substitute
[self.tableView reloadData];
with
[self.tableView reloadSections:[NSIndexSet indexSetWithIndex:0] withRowAnimation:UITableViewRowAnimationFade];