Question

// Create and add a sub view
CGRect viewRect = CGRectMake(0, 0, 200, 200);
UIView *a_sub_view = [[UIView alloc] initWithFrame : viewRect];

[window addSubview : a_sub_view];

After adding the above 3 lines of code, xcode produces no errors or warnings. But the sub-view is not showing at all. The sample program seems to be running exactly as before. Hope that somebody knowledgable could help.

Answer 1

I find it useful to set the background color so I know where the view is and the boundaries.

a_sub_view.backgroundColor = [UIColor redColor];

In your example, you’re create an empty view so you won’t ‘see’ anything.