ios - 调用网络服务时显示 UIActivityIndi​​cator

Question

我需要在等待 Web 服务的响应时显示 UIActivityIndi​​cator。我到底应该把它的代码放在哪里？？它不是这样工作的。事件指示器不显示。

我需要使用异步请求才能显示它吗？？

    -(void)callWebService
    {
        [self.customercareSearchbar resignFirstResponder];
        [self.SRResultDictionary removeAllObjects];
        NSLog(@"web service called");
        NSString *srn = _SRNumber;
        NSString *serviceURL = [NSString stringWithFormat:@"https://abcdef...];

        @try {
UIActivityIndicatorView *activity = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
                [self.view addSubview:activity];

                activity.center = self.view.center;
                [self.view bringSubviewToFront:loadView];
                activity.hidesWhenStopped = YES;
                [activity setHidden:NO];

                [activity startAnimating];

            NSURLRequest *request = [NSURLRequest requestWithURL:[NSURL URLWithString:serviceURL]];
            NSURLResponse *serviceResponse = nil;
            NSError *err = nil;

            NSData *responseData = [NSURLConnection sendSynchronousRequest:request returningResponse:&serviceResponse error:&err];

            [activity stopAnimating];

            NSMutableDictionary *parsedData = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error:&err];

            if(!parsedData)
            {
                NSLog(@"data not parsed");
                UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"ERROR" message:@"Problem in Network. Please Try Again!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
                [alert show];
                [self.customerCareTableView setHidden:YES];
            }
            else
            {
                NSLog(@"parsed");
                NSLog(@"parsed.. the size is %lu", (unsigned long)[parsedData count]);
                NSLog(@"%@", parsedData);

                NSString *status = [parsedData objectForKey:@"ns:Status"];
                NSLog(@"the status is %@", status);
                if([status isEqualToString:@"Success"])
                {
                    NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

                    if([[prefs objectForKey:@"SwitchState"] isEqualToString:@"OFF"])
                    {
                        //do nothing
                    }

                    else
                    {
                        [self saveNumberInDatabase:srn];
                    }

                    NSMutableDictionary *third = [parsedData objectForKey:@"ListOfXrxLvServiceRequest"];
                    NSLog(@"internal dict is %@", third);

                    self.SRResultDictionary = [third objectForKey:@"ServiceRequest"];

                    [self.customerCareTableView reloadData];
                    [self.customerCareTableView setHidden:NO];
                }

                else if([status isEqualToString:@"Record Not Found"])
                {
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Invalid Entry" message:@"Please enter a valid Service Request Number" delegate:self cancelButtonTitle:@"Ok" otherButtonTitles:nil];
                    [alert show];
                    [self.customerCareTableView setHidden:YES];
                }

                else
                {
                    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"ERROR" message:@"Problem in Network. Please Try Again!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles: nil];
                    [alert show];
                    [self.customerCareTableView setHidden:YES];
                }
            }
        }

        @catch (NSException *exception)
        {
            UIAlertView *alert = [[UIAlertView alloc] initWithTitle:NULL message:@"Problem In Network Connection. Please Try Again!" delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
            [alert show];
            [self.customerCareTableView setHidden:YES];
        }
        @finally {

        }
    }

Answer 1

是的，问题是同步请求。

如果可以发送 ASynchronous 请求，那么尝试这样做。

[NSURLConnection sendAsynchronousRequest:request queue:nil completionHandler:^(NSURLResponse *response, NSData *data, NSError *connectionError) {

// stop activity

// write other code you want to execute

}];