Best practice to calculate view size within loadView method

Question

What is the best practice to calculate the view size in the loadView method (in an UIViewController) without a XIB file?

Here is my solution:

- (void)loadView {

  //Calculate Screensize
  BOOL statusBarHidden = [[UIApplication sharedApplication] isStatusBarHidden ];
  BOOL navigationBarHidden = [self.navigationController isNavigationBarHidden];
  BOOL tabBarHidden = [self.tabBarController.tabBar isHidden];

  CGRect frame = [[UIScreen mainScreen] bounds];

  if (!statusBarHidden) {
    frame.size.height -= [[UIApplication sharedApplication] statusBarFrame].size.height; 
  }
  if (!navigationBarHidden) {
    frame.size.height -= self.navigationController.navigationBar.frame.size.height; 
  }
  if (!tabBarHidden) {
    frame.size.height -= self.tabBarController.tabBar.frame.size.height; 
  }

  UIView *v = [[UIView alloc] initWithFrame: frame];
  [v setBackgroundColor: [UIColor whiteColor] ];
  [v setAutoresizingMask: UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight ];
  [self setView: v ];
  [v release];      
}

Is this code okay, or should I edit something?

Adolphus

Answer 1

The docs recommend using [[UIScreen mainScreen] applicationFrame] to get the screen bounds without the status bar

Comply

thx, here are the docs for anyone who is interested: developer.apple.com/library/IOs/documentation/UIKit/Reference/… – Adolphus

i can – Comply

What do you base this claim on? Do you have a reference? – Premier

Answer 2

so for anyone who want to know a best practice example:

#pragma mark -
#pragma mark LoadView Methods
- (void)loadView {

  //Calculate Screensize
  BOOL statusBarHidden = [[UIApplication sharedApplication] isStatusBarHidden ];
  BOOL navigationBarHidden = [self.navigationController isNavigationBarHidden];
  BOOL tabBarHidden = [self.tabBarController.tabBar isHidden];
  BOOL toolBarHidden = [self.navigationController isToolbarHidden];

  CGRect frame = [[UIScreen mainScreen] applicationFrame];

  //check if you should rotate the view, e.g. change width and height of the frame
  BOOL rotate = NO;
  if ( UIInterfaceOrientationIsLandscape( [UIApplication sharedApplication].statusBarOrientation ) ) {
    if (frame.size.width < frame.size.height) {
      rotate = YES;
    }
  }

  if ( UIInterfaceOrientationIsPortrait( [UIApplication sharedApplication].statusBarOrientation ) ) {
    if (frame.size.width > frame.size.height) {
      rotate = YES;
    }
  }

  if (rotate) {
    CGFloat tmp = frame.size.height;
    frame.size.height = frame.size.width;
    frame.size.width = tmp;
  }


  if (statusBarHidden) {
    frame.size.height -= [[UIApplication sharedApplication] statusBarFrame].size.height;
  }
  if (!navigationBarHidden) {
    frame.size.height -= self.navigationController.navigationBar.frame.size.height;
  }
  if (!tabBarHidden) {
    frame.size.height -= self.tabBarController.tabBar.frame.size.height;
  }
  if (!toolBarHidden) {
    frame.size.height -= self.navigationController.toolbar.frame.size.height;
  }

  UIView *v = [[UIView alloc] initWithFrame: frame];
  v.backgroundColor = [UIColor whiteColor];
  v.autoresizingMask  = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

  self.view = v;
  [v release]; //depends on your ARC configuration
}

Adolphus

Answer 3

You are adjusting the height depend on the status bar and navigation bars.. But you have not done anything with respect to the origin of the view.

Fr

yes the origin is always {0, 0}. An if the navBar is visible the point 0,0 is under the navBar. or I'm wrong? – Adolphus