dispatch_async與XML解析器不工作

Question

我在uitable視圖解析XML數據的時候，這裏使用dispatch_async是我的代碼：

- (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]; 
} 

現在的UITableView不顯示任何數據。它在dispatch_async之前工作完美

Answer 1

我覺得你的代碼有問題。請重新加載表數據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]; 
     }); 
    });  
}