title: (NSTimer) creating a Timer Countdown
body: <p>I am trying to create a simple Countdown Timer so that when a player enters my game the timer begins from 60 down to 0. It seems simple but I am getting confused at how I write this.</p>
  
  <p>So far I have created a method within my GameController.m that looks like this:</p>
  
  <pre><code>-(int)countDownTimer:(NSTimer *)timer {
      [NSTimer scheduledTimerWithTimeInterval:-1
                                   invocation:NULL
                                      repeats:YES];
      reduceCountdown = -1;
      int countdown = [[timer userInfo] reduceCountdown];
      if (countdown &lt;= 0) {
          [timer invalidate];
      }
      return time;
  }
  </code></pre>
  
  <p>At the start of the game I initialise the integer Time at 60. The label is then being set within ViewController. But at the moment when I compile the code it just shows the label at 60 and doesn't decrement at all.</p>
  
  <p>Any help would be greatly appreciated - I am new to Objective-C.</p>
  
  <hr>
  
  <p><strong>EDIT</strong></p>
  
  <p>With some assistance from I have now separated the code into 2 separate methods. The code now looks like this:</p>
  
  <pre><code>-(void)countDown:(NSTimer *)timer {
      if (--time == 0) {
          [timer invalidate];
          NSLog(@"It's working!!!");
      }
  }
  
  -(void)countDownTimer:(NSTimer *)timer {
      NSLog(@"Hello");
      [NSTimer scheduledTimerWithTimeInterval:1
                                        target:self
                               selector:@selector(countDown:)
                                        userInfo:nil
                                        repeats:YES];
  }
  </code></pre>
  
  <p><strong>HOWEVER</strong>, the code is still not running properly and when I call the method [game countDownTimer] from my View Controller it breaks saying: "unrecognized selector sent to instance". Can anybody explain what is wrong here?</p>