UITableView重新加载数据需要永久

Question

我通过JSON解析了几个东西到一个表视图，但我有问题，解析需要大约一秒（我知道这是由于网络指标），但然后有一个巨大的延迟，直到数据出现在表格视图中。

我试图放置[tableView reloadData];在几个地方已经但没有成功。

这是我的代码。

我将mainThreadQueue和myClassicoAPI定义为一个宏。

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    arrayNeuheiten = [[NSArray alloc] init]; 
    arrayArtikelName = [[NSArray alloc] init]; 
    dictionaryNewStuff = [[NSDictionary alloc] init]; 

    [self parseJSONWithURL:myClassicoAPI]; 
    //[self performSelector:@selector(updateTableView) withObject:nil afterDelay:NO]; 

    [neuheietenTable reloadData]; 
} 

-(void)viewDidAppear:(BOOL)animated { 
    [super viewDidAppear:animated]; 

    [neuheietenTable reloadData]; 
} 

-(void) updateTableView { 
    [neuheietenTable reloadData]; 
} 

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

-(NSInteger)numberOfRowsInSection:(NSInteger)section { 

    return 1; 
} 

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { 

    //return (self.arrayNeuheiten.count<17)?self.arrayNeuheiten.count : 17; 

    return MIN(18, arrayNeuheiten.count); 

} 



-(void) parseJSONWithURL: (NSURL *) jsonURL { 

    dispatch_async(mainThreadQueue, ^{ 
     NSError *error = nil; 

     [UIApplication sharedApplication].networkActivityIndicatorVisible = YES; 

     NSString *json =[NSString stringWithContentsOfURL:jsonURL encoding:NSJSONWritingPrettyPrinted error:&error]; 

     if (error == nil) { 


      NSData *jsonData = [json dataUsingEncoding:NSJSONWritingPrettyPrinted]; 

      dictionaryNewStuff = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error]; 
      if (error == nil) { 
       dispatch_async(mainThreadQueue, ^{ 
        arrayArtikelName = [[dictionaryNewStuff valueForKey:@"newstuff"] valueForKey:@"Neuheiten"]; 
        arrayNeuheiten = [[dictionaryNewStuff valueForKey:@"newstuff"] valueForKey:@"Neuheiten"]; 
        [neuheietenTable reloadData]; 
        [UIApplication sharedApplication].networkActivityIndicatorVisible = NO; 
       }); 
      } else { 
       nil; 
      } 

     } else { 
      nil; 
     } 
    }); 

} 


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *CellIdentifier = @"NeuheitenCell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 

    if (cell == nil) 
    { 
     cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]; 
    } 

    cell.textLabel.text = [[arrayArtikelName objectAtIndex:indexPath.row] objectForKey:@"name"]; 

    return cell; 
} 

在此先感谢

康斯坦丁

Answer 1

你装上这是坏的mainthread的数据同步和阻塞的接口。 尝试使用NSURLConnection的加载你的JSON数据，并刷新你的UITableView在

(void)connectionDidFinishLoading:(NSURLConnection *)aConnection 

方法，你就大功告成了处理它的时候。

Answer 2

你好，我修改了一个公共网址和它的工作正常的代码。看其有用来解决问题的代码：

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    arrayNeuheiten = [[NSArray alloc] init]; 
    arrayArtikelName = [[NSArray alloc] init]; 
    dictionaryNewStuff = [[NSDictionary alloc] init]; 

    [neuheietenTable reloadData]; 
    NSURL *url = [NSURL URLWithString:@"http://122.182.14.104:3004/build/product/15.json"]; 
    [self parseJSONWithURL:url]; 
    //[self performSelector:@selector(updateTableView) withObject:nil afterDelay:NO]; 

} 

-(void)viewDidAppear:(BOOL)animated { 
    [super viewDidAppear:animated]; 
} 
- (void)didReceiveMemoryWarning 
{ 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 
} 

-(NSInteger)numberOfRowsInSection:(NSInteger)section { 

    return 1; 
} 

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { 

    //return (self.arrayNeuheiten.count<17)?self.arrayNeuheiten.count : 17; 
    return arrayArtikelName.count; 

} 



-(void) parseJSONWithURL: (NSURL *) jsonURL { 
    NSError *error = nil; 

    NSString *json =[NSString stringWithContentsOfURL:jsonURL encoding:NSJSONWritingPrettyPrinted error:&error]; 

    if (error == nil) { 


     NSData *jsonData = [json dataUsingEncoding:NSJSONWritingPrettyPrinted]; 

     dictionaryNewStuff = [NSJSONSerialization JSONObjectWithData:jsonData options:kNilOptions error:&error]; 
     if (error == nil) { 
      arrayArtikelName = [dictionaryNewStuff valueForKey:@"attributes"]; 
//   arrayNeuheiten = [[dictionaryNewStuff valueForKey:@"newstuff"] valueForKey:@"Neuheiten"]; 
      [neuheietenTable reloadData]; 
      [UIApplication sharedApplication].networkActivityIndicatorVisible = NO; 
     } else { 
      nil; 
     } 
    } 

} 


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{ 
    static NSString *CellIdentifier = @"NeuheitenCell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 

    if (cell == nil) 
    { 
     cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier]; 
    } 

    cell.textLabel.text = [[arrayArtikelName objectAtIndex:indexPath.row] objectForKey:@"name"]; 

    return cell; 
}