how to show activity indicator in iphone application while uploading data - iphone

Question

I am uploading data to server i want that when i click upload button then activity indicator should start and stop after the data is uploaded.
This is how i am uploading data but activity indicator not working.
-(IBAction)startSyncButtonAction{
[self startActivity];
CereniaAppDelegate *appDelegate = (CereniaAppDelegate *)[[UIApplication sharedApplication] delegate];
for (int i=0; i<[appDelegate.coffeeArray count]; i++) {
Coffee *coffeeObj = [appDelegate.coffeeArray objectAtIndex:i];
int mycount=[appDelegate.coffeeArray count];
NSLog(#"My Array count is %d",mycount);
NSString*device_Id=coffeeObj.device_Id;
NSString*R1=coffeeObj.R1;
NSString*R2=coffeeObj.R2;
NSString*R3=coffeeObj.R3;
NSString*R4=coffeeObj.R4;
NSString*R5=coffeeObj.R5;
NSString*R6=coffeeObj.R6;
NSString*R7=coffeeObj.R7;
NSString*R8=coffeeObj.R8;
NSString*R9=coffeeObj.R9;
NSString*R10=coffeeObj.R10;
NSString*R11=coffeeObj.R11;
NSString*R12=coffeeObj.R12;
NSString*R13=coffeeObj.R13;
NSString*R14=coffeeObj.R14;
NSString*update_date_time=coffeeObj.update_date_time;
NSString*teritory1=coffeeObj.teritory;
int mycount1=[appDelegate.coffeeArray count];
NSLog(#"My Array After delete is %d",mycount1);
NSLog(#"device_Id%#",device_Id);
NSLog(#"R1%#",R1);
NSLog(#"R2%#",R2);
NSLog(#"R3%#",R3);
NSLog(#"R4%#",R4);
NSLog(#"R4%#",R5);
NSLog(#"R4%#",R6);
NSLog(#"R4%#",R7);
NSLog(#"R4%#",R8);
NSLog(#"R4%#",R9);
NSLog(#"R4%#",R10);
NSLog(#"R4%#",R11);
NSLog(#"R4%#",R12);
NSLog(#"R4%#",R13);
NSLog(#"R4%#",R14);
NSLog(#"update_date_time%#",update_date_time);
NSString *post =[[NSString alloc] initWithFormat:#"device_Id=%#&R1=%#&R2=%#&R3=%#&R4=%#&R5=%#&R6=%#&R7=%#&R8=%#&R9=%#&R10=%#&R11=%#&R12=%#&R13=%#&R14=%#&update_date_time=%#&teritory1=%#",device_Id,R1,R2,R3,R4,R5,R6,R7,R8,R9,R10,R11,R12,R13,R14,update_date_time,teritory1];
NSLog(post);
NSURL *url=[NSURL URLWithString:#"http://celeritas-solutions.com/pah_brd_v1/pfizersurvey/SyncSurveySTD.php"];
NSData *postData = [post dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];
NSString *postLength = [NSString stringWithFormat:#"%d", [postData length]];
NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init] ;
[request setURL:url];
[request setHTTPMethod:#"POST"];
[request setValue:postLength forHTTPHeaderField:#"Content-Length"];
[request setValue:#"application/x-www-form-urlencoded" forHTTPHeaderField:#"Content-Type"];
[request setHTTPBody:postData];
NSError *error;
NSURLResponse *response;
NSData *urlData=[NSURLConnection sendSynchronousRequest:request returningResponse:&response error:&error];
NSString *data=[[NSString alloc]initWithData:urlData encoding:NSUTF8StringEncoding];
NSLog(#"%#",data);
}
for (int i=0; i<[appDelegate.coffeeArray count]; i++) {
Coffee *coffeeObj = [appDelegate.coffeeArray objectAtIndex:i];
[appDelegate removeCoffee:coffeeObj];
}
}
-(void)startActivity:(id)sender
{
NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
activityImageView.hidden=NO;
activityView.hidden=NO;
[activityView startAnimating];
[pool release];
}

Answer 1

Try below code but I am giving example you should modify it & use according to your need:
alert= [[UIAlertView alloc] initWithTitle:#"Loading\nPlease Wait..." message:nil delegate:self cancelButtonTitle:nil otherButtonTitles: nil];
[alert show];
UIActivityIndicatorView *indicator = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge];
indicator.center = CGPointMake(150, 100);
[indicator startAnimating];
[alert addSubview:indicator];
Use this line to dismiss indicator:
[alert dismissWithClickedButtonIndex:0 animated:YES];
Try. Best of luck.

Answer 2

For better user experience i will recommend you to use UIProgressHUD
UIProgressHUD* hud = [[UIProgressHUD alloc] initWithFrame:CGRectZero];
[hud setText:#"Loading, please wait."];
[hud showInView:someView];
...
[hud done];
...
[hud hide];
...
[hud release];

Answer 3

Are you 100% sure that activityView is not nil?? I don't see anywhere you set it to anything. Also, even it were not nil, have you added it to a view? activityView is just a regular UIView, it won't automatically appear in UIWindows.