dispatch_async与XML解析器不工作

Question

我在uitable视图解析XML数据的时候，这里使用dispatch_async是我的代码：

- (void) Parse{ 
    dispatch_async(dispatch_get_global_queue(0, 0), ^{ 
    NSString *post =[[NSString alloc] initWithFormat:@"http://messages.xml"]; 
    NSData *xmlData=[[NSData alloc]initWithContentsOfURL:[NSURL URLWithString:post]]; 
    xmlParserObject =[[NSXMLParser alloc]initWithData:xmlData]; 
    [xmlParserObject setDelegate:self]; 
    dispatch_async(dispatch_get_main_queue(), ^{ 
    [xmlParserObject parse]; 
    }); 
    }); 
    [messageList reloadData]; 
} 

现在的UITableView不显示任何数据。它在dispatch_async之前工作完美

Answer 1

我觉得你的代码有问题。请重新加载表数据dispatch_get_main_queue()

- (void) Parse { 
    dispatch_async(dispatch_get_global_queue(0, 0), ^{ 

     NSString *post =[[NSString alloc] initWithFormat:@"http://messages.xml"]; 
     NSData *xmlData=[[NSData alloc]initWithContentsOfURL:[NSURL URLWithString:post]]; 
     xmlParserObject =[[NSXMLParser alloc]initWithData:xmlData]; 
     [xmlParserObject setDelegate:self]; 
     [xmlParserObject parse]; 
     dispatch_async(dispatch_get_main_queue(), ^{ 
      [messageList reloadData]; 
     }); 
    });  
}