iOS: How to add more views after viewDidLoad - ios

Question

I am new to IOS programming. I am starting from the basic application created by XCode 4.3 (SingleView application).
Continuing from my above question, I was able to add Views programmaticaly to the main ViewController in the Appdelegate but If I want to do the same after the view has loaded (inside viewDidLoad), I am facing the trouble. I tried using the same logic of adding subviews but I am not sure if the view needs a refresh after adding inside 'viewDidLoad'
My views are very simple, here is the code
-(void)viewDidLoad
{
[super viewDidLoad];
UIBUtton *btn = [UIBUtton] alloc] initWithFrame:CGRect(10,10,50,50)];
[self.view addSubView:btn];
[self.view setNeedsDsiplay];
}
Can someone please help?

Answer 1

You are not instantiating the UIButton correctly. You should use buttonWithType: method.
For example:
- (void)viewDidLoad {
[super viewDidLoad];
UIButton * btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[btn setFrame:CGRectMake(10.0, 10.0, 50.0, 50.0)];
[[self view] addSubview:btn];
}

Answer 2

You have placed square brackets at wrong places. Probably you are new to Objective-C. You should pay more attention to learning syntax before creating UI based apps.
UIBUtton *btn = [UIBUtton] alloc] initWithFrame:CGRect(10,10,50,50)];
Should be:
UIBUtton *btn = [[UIBUtton alloc] initWithFrame:CGRect(10,10,50,50)];
Also
[self.view setNeedsDsiplay];
is not needed.