Non-Blocking Long Running Tasks on iPhone

iOS applications containing long running tasks - such as HTTP requests or data processing - that block the main thread are annoying and often appear sluggish. The following snippet can be used to fix this issue:

//
//  SampleTableViewController.m
//  Sample
//
//  Created by Kevin Sylvestre on 10-04-22.
//  Copyright Kevin Sylvestre 2010. All rights reserved.
//

#import "SampleTableViewController.h"

@implementation SampleTableViewController

#pragma mark - Helpers

- (void)load
{
  [NSThread sleepForTimeInterval:4.0];
  self.results = [NSArray arrayWithObjects:@"Canada", @"England", @"France", @"Spain", nil];
  [self.view performSelectorOnMainThread:@selector(reloadData) withObject:nil waitUntilDone:NO];
}

#pragma mark - Main

- (void)viewDidLoad
{
  [super viewDidLoad];

  NSOperationQueue *queue = [[[NSOperationQueue alloc] init] autorelease];
  [queue addOperation:[[[NSInvocationOperation alloc] initWithTarget:self selector:@selector(load) object:nil] autorelease]];
}

@end