UIActivityIndicator not showing over UITableView when reloading new data - ios

Question

My basic problem is that I cannot seem to work out how to bring the Activity indicator to the top so I can show that a process is running while new data is populating the UITableView. To load new data I am using a Segmented Control. When segment 0 is pressed it will load the first xml feed and when segment 1 is pressed it will load a second xml feed. I have tried using dispatch_queue_t etc. it does load the information and repopulate the table, it just doesn't show the indicator.
This is the code i am currently using.
if (Seg.selectedSegmentIndex == 0) {
timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:#selector(loading) userInfo:nil repeats:YES];
dispatch_queue_t loader = dispatch_queue_create("a", NULL);
dispatch_async(loader, ^{
xml = [[XmlParser alloc]init];
url = [NSURL URLWithString:kTodaysReport];
dict = [[NSMutableDictionary alloc]init];
[xml loadXML:url];
[tableView addSubview:ActInd];
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleUpdate:) name:#"update" object:nil];
});
});
}
else if (Seg.selectedSegmentIndex ==1){
// tableView = [[UITableView alloc]init];
timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:#selector(loading) userInfo:nil repeats:YES];
dispatch_queue_t loader = dispatch_queue_create("a", NULL);
dispatch_async(loader, ^{
xml = [[XmlParser alloc]init];
url = [NSURL URLWithString:kMonthsReport];
dict = [[NSMutableDictionary alloc]init];
[xml loadXML:url];
[tableView addSubview:ActInd];
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleUpdate:) name:#"update" object:nil];
});
});
}
Thanks in advance.
EDIT:Relevant code
- (void)viewDidLoad
{
[super viewDidLoad];
dispatch_queue_t loader = dispatch_queue_create("a", NULL);
timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:#selector(loading) userInfo:nil repeats:YES];
dispatch_async(loader, ^{
xml = [[XmlParser alloc]init];
url = [NSURL URLWithString:kTodaysReport];
dict = [[NSMutableDictionary alloc]init];
[xml loadXML:url];
[UiTableView addSubview:ActInd];
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleUpdate:) name:#"update" object:nil];
[ActInd stopAnimating];
[UiTableView reloadData];
});
});
}
-(void)handleUpdate:(NSNotification*)notification{
mainArray = [xml parsedArray];
[UiTableView reloadData];
}
-(void)loading{
if (![xml val]) {
[ActInd startAnimating];
}else
{
[ActInd stopAnimating];
[UiTableView reloadData];
}
}
-(IBAction)segvalueChange:(id)sender{
if (Seg.selectedSegmentIndex == 0) {
timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:#selector(loading) userInfo:nil repeats:YES];
dispatch_queue_t loader = dispatch_queue_create("a", NULL);
dispatch_async(loader, ^{
xml = [[XmlParser alloc]init];
url = [NSURL URLWithString:kTodaysReport];
dict = [[NSMutableDictionary alloc]init];
[xml loadXML:url];
[UiTableView addSubview:ActInd];
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleUpdate:) name:#"update" object:nil];
});
});
}
else if (Seg.selectedSegmentIndex ==1){
// UiTableView = [[UITableView alloc]init];
timer = [NSTimer scheduledTimerWithTimeInterval:(1.0/2.0) target:self selector:#selector(loading) userInfo:nil repeats:YES];
dispatch_queue_t loader = dispatch_queue_create("a", NULL);
dispatch_async(loader, ^{
xml = [[XmlParser alloc]init];
url = [NSURL URLWithString:kMonthsReport];
dict = [[NSMutableDictionary alloc]init];
[xml loadXML:url];
[UiTableView addSubview:ActInd];
dispatch_async(dispatch_get_main_queue(), ^{
[[NSNotificationCenter defaultCenter]addObserver:self selector:#selector(handleUpdate:) name:#"update" object:nil];
});
});
}
else{
}
}

Answer 1

The problem is that you are interacting with the UI on a background thread. Move all UI related code (including that which interacts with the activity view) into the GCD block for the main thread.