CODEWITHSUNDEEP
iphoneiosobjective-ccocoa-touch
MasterRazer
MasterRazer

Reputation: 1377

Call method only once every app launch

Hey guys at Stackoverflow!

I need your help. I am looking for a way to call my method only once after the application has launched and "save" the state of the color of the UIView. At first I will show you my code, that I can explain it in a better way:

-(void)viewWillAppear:(BOOL)animated {

NSArray *colors = [NSArray arrayWithObjects:[UIColor myWhiteColor],[UIColor myBlueColor],[UIColor myCyanColor],[UIColor myGreenColor],[UIColor myOrangeColor],[UIColor myPurpleColor],[UIColor myRedColor],[UIColor myViolettColor],[UIColor myYellowColor], nil];

NSInteger randomIndex = random() % [colors count];

colorTransparentView.backgroundColor = [colors objectAtIndex:randomIndex];
colorTransparentView.opaque = NO;
colorTransparentView.alpha = 1.0;

}

Now I explain you my issue. As you can see, the code above changes the color of the UIView, every time the "viewWillAppear" method was called. The code randomly changes the color of the UIView(in the .xib) which is linked with an IBOulet to the header file. The problem is that every time I get back to the view I will get a different color.

However, I want to set the random color of the UIView only once the application started. This color should stay until the application was closed from the Multitasking. I can't see any way to solve this. I tried to call the code in the applicationDidFinishedLaunchingWithOptions method, but I wasn't succsessful.

Also I tried the dispatch_once method to call it only once, but as you may think of the color was never called again, so the view got no color the second time loaded.

I really would appreceate if you could help me with this.

Thanks in Advance,

Noah

EDIT:

My header:

@interface ViewController : UIViewController {

    IBOutlet UIView *colorTransparentView;
}


@end

Upvotes: 1

Views: 351

Answers (2)

pickwick
pickwick

Reputation: 3154

Use dispatch_once. You can read up on singleton approaches in general, but this is the recommended approach.

Upvotes: 0

hasan
hasan

Reputation: 24195

What about using a static variable? initialise it with 0 and after changing color in your view will appear. set it to 1 and keep checking it.

int static colortaken = 0;
int static colorindex;
- (void)viewWillAppear:(BOOL)animated
{

   NSArray *colors = [NSArray arrayWithObjects:[UIColor myWhiteColor],[UIColor myBlueColor],[UIColor myCyanColor],[UIColor myGreenColor],[UIColor myOrangeColor],[UIColor myPurpleColor],[UIColor myRedColor],[UIColor myViolettColor],[UIColor myYellowColor], nil];
   if (colortaken == 0)
   {
      NSInteger randomIndex = random() % [colors count];
      colorindex = randomIndex;
      colorTransparentView.backgroundColor = [colors objectAtIndex:randomIndex];
      colorTransparentView.opaque = NO;
      colorTransparentView.alpha = 1.0; 
   }
   else
   {
      // do nothin  
      colorTransparentView.backgroundColor = [colors objectAtIndex:colorindex];
      colorTransparentView.opaque = NO;
      colorTransparentView.alpha = 1.0;
   }

   // at end
   colortaken = 1;
}

Upvotes: 3

Related Questions