iphone:objective c: UIView animation? - iphone

Question

I have read apple documentation: http://developer.apple.com/library/ios/#documentation/WindowsViews/Conceptual/ViewPG_iPhoneOS/AnimatingViews/AnimatingViews.html#//apple_ref/doc/uid/TP40009503-CH6-SW1
For iOS3.0 and earlier, using this:
Method1:
[UIView beginAnimations:#"ShowHideView" context:nil];
[UIView setAnimationCurve:UIViewAnimationCurveEaseOut];
...
The new one, iOS4, can do this:
Method2:
[UIView animateWithDuration:1.0 animations:^{
firstView.alpha = 0.0;
secondView.alpha = 1.0;
}];
Q1. What I want to know is, in earlier method, they have this "ShowHideView" in beginAnimations, is that method a built-in one?
Q2. Are there any others built-in methods for animation in beginAnimations? If yes, where can I find all those methods?
Q3. And lastly, can I use those methods in latter method(method2) call?

Answer 1

You can get all the answers to your questions in the UIView Class Reference.
Q1: ShowHideView, as you have it, is not a method at all. It is simply an "application-supplied identifier for the animations". In reality, you don't need it. When I use this method, I just use NULL instead of supplying an identifier there.
Q2: You don't set animations in the beginAnimations:context: call. You even illustrate it there by calling setAnimationCurve. You can set the animations from this typedef.
Q3: Again, you don't declare animation types in animateWithDuration:animations: call either. Utilize setAnimationCurve: to do that in that example as well.

Answer 2

Blocks have the benefit of being able to nest the animations (in a queue almost) using the [UIView animateWithDuration:animations:completion:] selector. You can nest another call to this method inside the finished block like so:
[UIView animateWithDuration:1.0 animations:^{
// your first animations
} completion:^(BOOL finished) {
[UIView animateWithDuration:1.0 animations:^{
// more animations
} completion:^(BOOL finished) {
// ... maybe even more
}]
}]
I abuse this in my code and find it much easier than using the beginAnimations/commitAnimations code. And, with iOS 5 approaching, the days of needing to support iOS 3.x are slipping away.