Change UITextView with Floating Number Variable - ios

Question

I want to display an UITextView on centre, dynamically both for 3.5 inch display and 4 inch display. but it has top and bottom 'padding' 20 pts.
So I create this code to measure UIView's height:
CGFloat screenHeight = _screen.frame.size.height;
float scrollHeight = screenHeight - 40;
then I add this line to set the screen :
_screen.frame = CGRectMake(20, 40, 320, scrollHeight);
but I see no difference on my 4 inch iPod touch... what did I do wrong?
UPDATE :
here's my .h file :
#property (strong, nonatomic) IBOutlet UIView *screen;
and here's my .m file :
- (void)viewDidLoad
{
[super viewDidLoad];
CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
_screen.frame = CGRectMake(20, 40, 320, screenHeight);
}

Answer 1

You can get the screen informations for sure like this:
screenWidth = [UIScreen mainScreen].bounds.size.width;
screenHeight = [UIScreen mainScreen].bounds.size.height;
CGRect statusBarFrame = [[UIApplication sharedApplication] statusBarFrame];
You can calculate with these dynamically every height or width you want, and your views will got the right frame.
EDIT:
- (void)viewDidLoad
{
[super viewDidLoad];
CGFloat screenHeight = [UIScreen mainScreen].bounds.size.height;
_screen.frame = CGRectMake(20, 40, 320, screenHeight);
}
this will make you the _screen will start at 40 and it will hang out at the bottom 40 too.
if you want to make a centered view make it like this:
_screen.frame = CGRectMake(20, 40, screenWidth-40, screenHeight-80);
and don't forget to add the screen to the superview like:
[self.view addSubview:_screen];
I hope it helps.
And one more tip: You can see your _screen frame, if you set _screen.backgroundcolor = [UIColor orangeColor]; for testing !