Question

On Callback

On Iphone

File A:

@protocol servicedelegate
-(void)taskCompleted:(NSDcitionary*) dict;
@end

-(void) performtask
callback=@”taskCompleted:”;

[(id)delegate performSelector:NSSelectorFromString(callback) withObject:data];

File B:

-(void) taskcompleted:(NSDictionary*)dict
{

//don something when File A fisnihed the taskcompleted and have the data
// this callback on File B will be awaken from File A’s delegate function
}

The question How does Android implement the above, File A waiting to getting the data, and nobody knows how long, but once finished, File B would awaken by the delegate callback function of taskcompleted.

Answer 1

There are a couple different ways:

• Handlers
• AsyncTask

I’m a fan of AsyncTask myself, but they require more boilerplate. Handlers can often be simpler.