Reload contents at startup

Question

I've been banging my head against the wall for several days trying to understand how to perform an action as soon as the application starts.

Basically I want to download a plist from my website if the user turns on a switch that determines if he wants to download new contents at startup.

Point is that:

"A" class has the method to reload the contents;
"B" class has the switch that, if turned on, tells the delegate to perform the reload contents method as soon as the application starts

Now, I don't know how to tell the AppDelegate to run the method of class "A" if the switch of class "B" is turned on. Obviously I need to use NSUserDefaults, but i'm pretty lost after that.

Can anyone make things clearer? Or, is there a more comfortable workaround to do it?

janusfidel · Accepted Answer · 2012-09-03T12:48:23.957

yes you can do this using NSUserDefaults

in your class b.

-(void)swithChanged
 {
   NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    //check if !null
   if(![[defaults objectForKey:@"shouldDownload"]isKindOfClass:[NSNull class]]){
         if([(NSNumber*)[defaults objectForKey:@"shouldDownload"]boolValue])
          {
             [defaults setObject:[NSNumber numberWithInt:0] forKey:@"shouldDownload"];
             [defaults synchronize];
          }else{
             [defaults setObject:[NSNumber numberWithInt:1] forKey:@"shouldDownload"];
             [defaults synchronize];

         }
     }else{
       //set your NSUserDefault here for the first time
    }

}

in your AppDelegate

- (void)applicationDidBecomeActive:(UIApplication *)application{
   NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    //check if !null
   if(![[defaults objectForKey:@"shouldDownload"]isKindOfClass:[NSNull class]]){
         if([(NSNumber*)[defaults objectForKey:@"shouldDownload"]boolValue])
          { 
              //you can write the downloadData method in this appDelegate,
             //[self downloadData]

             //OR
             AClass *aClass = [AClass alloc]init];
             [aClass downloadData];
          }else{
            //do not download
         }
     }else{
       //the default behaviour of app, download or not?
    }

}

Thanks a lot for the answer! Just a question: in AppDelegate, when you've wrote [self downloadData], i should initialize my "A" class then perform the method, right!? — Phillip, Sep 03 '12 at 12:42

score 1 · Answer 2 · edited May 23 '17 at 12:27

1

Here's a post that could help you understand the flows during application start-up: http://www.cocoanetics.com/2010/07/understanding-ios-4-backgrounding-and-delegate-messaging

Also, check this post: applicationWillEnterForeground vs. applicationDidBecomeActive, applicationWillResignActive vs. applicationDidEnterBackground

edited May 23 '17 at 12:27

Community

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answered Sep 03 '12 at 12:11

Bijoy Thangaraj

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Reload contents at startup

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