Question

我使用SBJSON Framework示例使用JSON feed从twitter下载数据。下载完成后，我将numberofrows改为0.我是否必须在下载数据之前等待，或者我在代码中缺少任何数组的启动？

- (void)viewDidLoad {
[super viewDidLoad];


// Add the view controller's view to the window and display.
responseData = [[NSMutableData data] retain];
self.twitterArray = [NSMutableArray array];
NSURLRequest *request = [NSURLRequest requestWithURL:
[NSURL URLWithString:@"http://search.twitter.com/search.json?q=mobtuts&rpp=5"]];


[[NSURLConnection alloc] initWithRequest:request delegate:self];

[super viewWillAppear:animated];
}


 - (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response {
[responseData setLength:0];
   }

 - (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data {
[responseData appendData:data];
  }


 - (void)connectionDidFinishLoading:(NSURLConnection *)connection {
[connection release];

NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];  
[responseData release];  

NSDictionary *results = [responseString JSONValue];  

self.twitterArray = [results objectForKey:@"results"]; 

    [self.tableView reloadData]; // Correct way

 }

 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
// Return the number of rows in the section.
NSLog(@"count : %d", [self.twitterArray count]); // Gets the count 0 here.
return [self.twitterArray count];
 }

Answer 1

除非您使用+sendSynchronousRequest:returningResponse:error:，否则NSURLConnection是异步的。下载完成后，您需要致电[self.tableView reloadData]，并且twitterArray设置为您的结果。这将强制tableView重新读取其所有数据源/委托方法。

- (void)connectionDidFinishLoading:(NSURLConnection *)connection {
  [connection release];

  NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];  
  [responseData release];  

  NSDictionary *results = [responseString JSONValue];  

  self.twitterArray = [results objectForKey:@"results"]; 

  [self.tableView reloadData]; // <-- add this here
}

在numberofrowsinsections中计数0

1 个答案: