ios - json解析中事件指示器的使用

Question

我正在处理应用程序，并且在登录过程中我必须使用 activityindicator，但我没有在下面的代码中使用 activityindicator 的代码:-

- (IBAction)Login:(id)sender
{
    NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration defaultSessionConfiguration];
    NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];

    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:BaseUrl@"login"]];

    NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:url
                                                           cachePolicy:NSURLRequestUseProtocolCachePolicy
                                                       timeoutInterval:60.0];

    [request addValue:@"application/x-www-form-urlencoded" forHTTPHeaderField:@"Content-Type"];


    [request addValue:@"*/*" forHTTPHeaderField:@"Accept"];

    [request setHTTPMethod:@"POST"];

    NSString *mapData = [NSString stringWithFormat:@"userName=g&userPassword=123456&api_key=ZWZ&api_password=1" ];

    NSData *postData = [mapData dataUsingEncoding:NSASCIIStringEncoding allowLossyConversion:YES];

    [request setHTTPBody:postData];


    NSURLSessionDataTask *postDataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) {

        if(error == nil)
        {

            NSString * text = [[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding];
            NSLog(@"text= %@",text);

            NSError *error = nil;
            NSDictionary *json = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:&error];

            if(error!=nil)
            {
                NSLog(@"error = %@",error);

            }

            dispatch_async(dispatch_get_main_queue(), ^{
                [self checkUserSuccessfulLogin:json];
            });
        }
        else{

            NSLog(@"Error : %@",error.description);

        }


    }];


    [postDataTask resume];




}

登录后转到其他页面需要时间。请帮助我。

Answer 1

使用下面的代码

//main thread
UIActivityIndicatorView *spinner = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
spinner.center = CGPointMake([[UIScreen mainScreen]bounds].size.width/2, [[UIScreen mainScreen]bounds].size.height/2);

//if you want to add to window, use this below one
[appdelegate.window addSubview:spinner];

//or if you want to add to view, use below one
 [self.view addSubView:spinner];

[spinner startAnimating];


dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0),^{

    dispatch_async(dispatch_get_main_queue(), ^{

   //after your server call or parsing or something you can call this to stop animating 

   [spinner stopAnimating];
  });
  });