Pass BOOL value

Question 1

This code doesn't make sense:

self.pointerFirstClass.myBOOL;
NSLog(@"%d", firstClass.myBOOL); => This gives 0!

The first line doesn't do anything. You're not assigning anything to the property, and you're not doing anything with the value. Furthermore, the second line doesn't relate to the first line in any way that we can see from the code you've provided. Try this instead:

self.pointerFirstClass = [[FirstClass alloc] init];
self.pointerFirstClass.myBOOL = YES;
NSLog(@"myBOOL = %d", self.pointerFirstClass.myBOOL);

In other words, you need to be sure that self.pointerFirstClass points to a valid object. And then you need to make sure that you've assigned the value you want to the myBOOL property of that object.

Update: This looks like a case where you're talking to the wrong object. Look at this:

- (IBAction)onClick:(id)sender {
       AppDelegate *appDelegate = [[AppDelegate alloc] init];

This is surely not what you really want. The application object is a single object -- a real singleton, in fact, meaning that there is and can be only one application object. That object has a delegate object, and that's a specific instance of your AppDelegate class. In this code, though, you're creating a new instance of AppDelegate, one that's different from the one that the application is using. Any changes that are made to the actual application delegate in response to messages from the application will not be reflected in the new object that you've created.

What I think you want is to get the actual application delegate object, and you can do that using:

[[UIApplication sharedApplication] delegate];

So, change your code to look like this:

- (IBAction)onClick:(id)sender {
   AppDelegate *appDelegate = (AppDelegate*)[[UIApplication sharedApplication] delegate];;

   if (appDelegate.inRegion) {
      [self performSegueWithIdentifier:@"WelcomeToDetection" sender:self];
   }
   // note: you don't need an else clause if it doesn't do anything
}

That way, you'll be talking to the same object that the app uses, which is the one that has the inRegion property set in response to the location manager call.

Question 2

UPDATE - Now we can see your code the problem is obvious, you are trying to access the appDelegate by creating a new one...

- (IBAction)onClick:(id)sender {
       AppDelegate *appDelegate = [[AppDelegate alloc] init];

Instead you should be doing this....

- (IBAction)onClick:(id)sender {
        AppDelegate *appDelegate = [[UIApplication sharedApplication] delegate]

--

Not sure if you are posting your actual code? but the first example you give...

self.pointerFirstClass.myBOOL;
NSLog(@"%d", firstClass.myBOOL); => This gives 0!

Shouldn't the second line be

NSLog(@"%d", self.pointerFirstClass.myBOOL);

Also this property...

@property FirstClass *pointerFirstClass;

Won't retain it once you've set it, it needs to be

@property (nonatomic,strong) FirstClass *pointerFirstClass;

In the second example...

FirstClass *firstClass = [[FirstClass alloc] init];
if (firstClass.myBOOL){
      //Do something
}
NSLog(@"%d", firstClass.myBOOL); => This gives 0!

You allocate and initialise a new FirstClass object and then check the property straight away, if you are not setting this to YES in the init then it will be false

Like I say, maybe you're not posting your actual code?

Question 3

I guess what you want is initializing myBOOL to 1. If so, you need do something as following

@implement FirstClass
- (id)init
{
    self = [super init];
    if(self) {
        _myBOOL = 1;
    }
    return self;
}
// Other methods
@end

EDIT:

The comments is why you get 0.

- (IBAction)onClick:(id)sender {
   AppDelegate *appDelegate = [[AppDelegate alloc] init]; // this is the problem.
                                                          // you create a new appdelegate,
                                                          // and never call locationManager:didDetermineState:forRegion:

  if (appDelegate.inRegion) {

     [self performSegueWithIdentifier:@"WelcomeToDetection" sender:self];

   }
   else
 {
      //Do Nothing
   }
}

rewrite your code as following:

- (IBAction)onClick:(id)sender {
   AppDelegate *appDelegate = [UIApplication sharedApplication].delegate;

  if (appDelegate.inRegion) {
     [self performSegueWithIdentifier:@"WelcomeToDetection" sender:self];

   }
   else
 {
      //Do Nothing
   }
}