iOS开发，从网络中成功获取到数据源，却在UITableView中不显示，求解

网络获取的数据：

代码：
#import "SecondViewController.h"

@interface SecondViewController ()

@property NSMutableData *mutableData;
@property NSString *string;
@property NSMutableArray *courses;

@end

@implementation SecondViewController

• (void)viewDidLoad { NSString path = @"http://***************************"; NSURL *url = [NSURL URLWithString:path]; NSURLRequest *request = [NSURLRequest requestWithURL:url]; NSURLConnection *connection = [NSURLConnection connectionWithRequest:request delegate:self]; [connection start]; [super viewDidLoad]; self.classBarItem.badgeValue = nil;

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

• (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response{
  NSLog(@"%@", response);
  }

• (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data{
  if(_mutableData == nil){
  _mutableData = [[NSMutableData alloc]init];
  }
  [_mutableData appendData:data];
  }

• (void)connectionDidFinishLoading:(NSURLConnection *)connection{
  _string = [[NSString alloc]initWithBytes:[_mutableData bytes] length:[_mutableData length] encoding:NSUTF8StringEncoding];
  NSJSONSerialization *json_courses = [NSJSONSerialization JSONObjectWithData:_mutableData options:0 error:nil];
  NSMutableDictionary *json = [NSJSONSerialization JSONObjectWithData:_mutableData options:0 error:nil];
  _courses = [[NSMutableArray alloc] init];
  for(int i = 0; i < [json count]; i++){
  NSString *tag = @"course";
  NSString *str_i = [[NSString alloc]initWithFormat:@"%i",i];
  tag = [tag stringByAppendingString:str_i];
  NSJSONSerialization *json_course = [json_courses valueForKey:tag];
  NSString *name = [json_course valueForKey:@"courseName"];
  NSLog(@"%@",name);
  [_courses addObject:name];
  }
  NSLog(@"%@",_courses);
  //获取NSMuTableArray中第n个元素的值
  //NSLog(@"%@", [_courses objectAtIndex:1]);
  _mutableData = nil;
  }

• (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
  return 1;
  }

• (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
  NSLog(@"Array count is %i",[_courses count]);
  return [_courses count];
  }

  • (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"courses" forIndexPath:indexPath];
    cell.textLabel.text = [_courses objectAtIndex:[indexPath row]];
    // Configure the cell...

    return cell;
    }

/*
// Override to support conditional editing of the table view.

• (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the specified item to be editable. return YES; } */

/*
// Override to support editing the table view.

• (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { // Delete the row from the data source [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade]; } else if (editingStyle == UITableViewCellEditingStyleInsert) { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */

/*
// Override to support rearranging the table view.

• (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { } */

/*
// Override to support conditional rearranging of the table view.

• (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the item to be re-orderable. return YES; } */

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

• (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender { // Get the new view controller using [segue destinationViewController]. // Pass the selected object to the new view controller. } */

@end

个人分析是：该类先创建了tableview然后才获取网络数据源，可是不知道怎么解决

问题已经自行解决，原因如下：
由于获取网络数据并不在主线程中进行，所以程序会先执行后面的代码，最终导致程序虽然获得了数据源，却没有在tableview中显示出来。
此时只需要在connectionDidFinishLoading方法的末尾增加一句“[self.tableView reloadData];”来重载数据即可！