CODEWITHSUNDEEP
iosuitableviewxml-parsingdispatch
user1084420
user1084420

Reputation: 5

iOS: table view created before xml parsing complete

OK I'm hoping I'm missing something basic here - I am not very expert at this. It should be self-explanatory without example code: I parse a web-hosted xml file consisting of a list of titles to be displayed in a tableView and associated URLs to pass to a webView when a cell is selected. The parsing happens in the tableView into a dictionary. If I parse on the main thread it works nicely but I'm worried about hanging the UI if the signal is poor. So I wrap the parsing call in a dispatch queue as per examples on here and now it presents an empty table. But if I go back up the view hierarchy and try again (it's embedded in a navigation controller) then it works, there is my table fully populated. I'm assuming that by using a secondary thread somehow the table is created before the content array is populated. How do I get round this? Thanks! Andrew

Upvotes: 0

Views: 390

Answers (2)

Midhun MP
Midhun MP

Reputation: 107201

Implement the - (void)parserDidEndDocument:(NSXMLParser *)parser delegate method of NSXMLParser. And call reloadData of your tableView from that method.

- (void)parserDidEndDocument:(NSXMLParser *)parser
{
   dispatch_sync(dispatch_get_main_queue(), ^{
       [yourTable reloadData];
   });
}

Refer NSXMLParserDelegate

Upvotes: 1

dasdom
dasdom

Reputation: 14073

If you pares in a dispatch queue you have to update the UI on the main queue.

I am doing something similar. Here is my code:

dispatch_queue_t imgDownloaderQueue = dispatch_queue_create("imageDownloader", NULL);
dispatch_async(imgDownloaderQueue, ^{
    NSString *avatarUrlString = [avatarImageDictionary objectForKey:@"url"];
    avatarImage = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:avatarUrlString]]];

    dispatch_sync(dispatch_get_main_queue(), ^{
        id asyncCell = [self.tableView cellForRowAtIndexPath:indexPath];
        [[asyncCell avatarImageView] setImage:avatarImage];
    });
});

Upvotes: 0

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