Create a UIButton with (or without) memory

Question

I'm trying to add a UIButton with code (not Interface Builder).

Some examples say you MUST alloc and release memory for the button.

Others use buttonWithType and magically create a button without alloc'ing any memory at all.

How is that possible?

(Both seem to work fine.)

Which of the 2 methods do I want to use... and when? Are there some huge benefits to 1 method or another?

PLEASE don't tell me to just go "read the docs". The docs are the REASON I am here. They rarely seem to explain things without leaving out tons of 'missing info'.

Answer 1

Both works. The +buttonWithType: method is a convenient method, which is similar to

[[[UIButton alloc] initWithType:type] autorelease];

Since it is already -autorelease'd, you cannot -release it.

For built-in buttons (e.g. rounded rectangular, info buttons, etc.), you must use +buttonWithType: because there is no other ways to create them. Otherwise, both choices are fine.

Answer 2

buttonWithType: does use memory, but it is autoreleased. This means that it will be released at some point in the future. So [UIButton buttonWithType:] is equivalent to [[[UIButton alloc] initWithFrame:] autorelease].

You can use either method, depending on whether you want to be explicit or not about releasing.