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BOOK: Beginning iOS 4 Application Development
This is the forum to discuss the Wrox book Beginning iOS 4 Application Development by Wei-Meng Lee; ISBN: 978-0-470-91802-9
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Old January 6th, 2011, 07:50 PM
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Default Chapter 4 page 97 UIButton Question

Can someone please explain to me why, at the top of page 97, the code is like this:

button = [UIButton buttonWithType:UIButtonTypeRoundedRect];


button = [[UIButton alloc] buttonWithType:UIButtonTypeRoundedRect];

How does the button object get allocated? Does the 'buttonWithType' method do the allocating itself?
Old January 9th, 2011, 03:53 PM
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+ (id)buttonWithType:(UIButtonType)buttonType is a class method that handles the allocation and initialization of a UIButton for you (note the + sign in front of the return value). It returns an autoreleased object. Many classes have convenience methods for creating members of the class: e.g. [NSDictionary dictionary], [NSString stringWithFormat:…] etc
In many cases this simplifies (less typing, easier memory management) the creation of a new object. With UIButton it is the only way, outside of Interface Builder, to create a button.

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