walden systems, objective c, geolocation, ios, CLLocationManager, desiredAccuracy, distanceFilter, startUpdatingLocation, stopUpdatingLocation, delegate, iphone, picture, screen, swipe, iphone, thread, nsthread

Create new thread

Objective-C defines a small but powerful set of extensions to the ANSI C programming language that enables sophisticated object-oriented programming. Objective-C is the native language for Cocoa programming�it�s the language that the frameworks are written in, and the language that most applications are written in. You can also use some other languages�such as Python and Ruby�to develop programs using the Cocoa frameworks. It�s useful, though, to have at least a basic understanding of Objective-C because Apple�s documentation and code samples are typically written in terms of this language.

Sometimes you might need to open a new thread on an iPhone or iPad app. There are many ways to accomplish this task and I would like to discuss one of the ways we are using here at Walden Systems, because we believe this is the most straightforward method to open a new thread.

Strategy to open a new thread is fairly simple: First, we need to create the new thread. Second, we need instantiate a new thread. Third, we need to start the new thread.

Here are actual code samples:

The first thing you need to do is to create a new method that will execute in the new thread. In this example, we will just have a message shown on the console

1   - ( void ) newMethod
2   {
3       NSLog(@"Executing new thread.");
4   }

Then you need to create a new thread using NSThread. The someMethod is the method name you want to run in the new thread :

1    NSThread *     thread ;
2    thread = [ [ NSThread alloc] initWithTarget : self
3                                 selector       : @selector( someMethod )
4                                 object         : nil ] ;

Finally, you need to start the new thread with the following line :

1    [ thread start ] ;

So, this is how a final code for creating and running a new thread will look like:

 1     NSThread *     thread ;
 2     thread = [ [ NSThread alloc] initWithTarget : self
 3                                  selector       : @selector( someMethod )
 4                                  object         : nil ] ;
 5     [ thread start ] ;
 6     ...
 7     - ( void ) newMethod
 8     {
 9         NSLog(@"Executing new thread.");
10     }