title: auto layout horizontal and vertical format together
body: <p>How to add horizontal and vertical visual format together in the constraintsWithVisualFormat ? There is just horizontal. I want to add V:|-50-[leftButton] and V:|-50-[rightButton] to it. How to do that? Create another NSLayoutConstraint? </p>
  
  <pre><code>- (void)viewDidLoad
  {
      [super viewDidLoad];
      UIButton *leftButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
      [leftButton setTitle:@"Left" forState:UIControlStateNormal];
      [leftButton setTranslatesAutoresizingMaskIntoConstraints:NO];
      [self.view addSubview:leftButton];
      UIButton *rightButton = [UIButton buttonWithType:UIButtonTypeRoundedRect];
      [rightButton setTitle:@"Right" forState:UIControlStateNormal];
      [rightButton setTranslatesAutoresizingMaskIntoConstraints:NO];
      [self.view addSubview:rightButton];
  
      NSArray *layoutConstraints = [NSLayoutConstraint constraintsWithVisualFormat:@"H:|-50-[leftButton(&gt;=80)]-50-[rightButton(&gt;=80)]" options:0 metrics:nil views:NSDictionaryOfVariableBindings(leftButton, rightButton)];
      [self.view addConstraints:layoutConstraints];
  }
  </code></pre>