title: Beginner with iOS - SIGABRT when referring to a simple method in my app?
body: <p>I'm just starting with iOS development, trying to call a method(function?) in my code. In my .h file I have:</p>
  
  <pre><code>- (void)changeColour;
  </code></pre>
  
  <p>in my .m file I have:</p>
  
  <pre><code>- (IBAction)leftSwipeDetected:(UISwipeGestureRecognizer *)sender {
  
      [self changeColour];
  
  }
  
  - (void)changeColour
  {
      colourCount++;
  
      switch (colourCount)
      {
          case 1:
  
              self.view.backgroundColor = [UIColor redColor];
              break;
  
          case 2:
  
              self.view.backgroundColor = [UIColor blueColor];
              break;
      }
  }
  </code></pre>
  
  <p>This prompts a SIGABRT abandonment when I run the program, where it didn't when I didn't try calling a method. Is there anything wrong with this?</p>
  
  <p>Thanks.</p>