Animating UIView frame.origin - animation

Question

I have seen some sample code online regarding a simple UIView slide-in or slide-out. It makes sense to have a UIView start with its coordinates off the screen (negative) and then the animation parameter simply changes the UIView's frame. So first question is: does this provide the most obvious method?
However, in my code, the frame origin is not assignable. I get the Xcode error for that line that says as much.
I simply want to do something like this inside an animation:
self.viewPop.frame.origin.y=100;
Any help is appreciated.
UPDATE
I have solved this problem. The technique I discovered is to assign your view's frame to another CGRect, and make changes to that CGRect, then assign it back to the frame:
CGRect frame = self.moveView.frame;
frame.origin.x = newvalue.
[UIView animateWithDuration:2.0 animations:^{
self.moveView.frame = frame;
}];

Answer 1

I have solved this problem. The technique I discovered is to assign your view's frame to another CGRect, and make changes to that CGRect, then assign it back to the frame:
CGRect frame = self.moveView.frame;
frame.origin.x = newvalue.
[UIView animateWithDuration:2.0 animations:^{
self.moveView.frame = frame;
}];

Answer 2

FWIW, it's nice to have a UIView category around for this type of thing:
#interface UIView (JCUtilities)
#property (nonatomic, assign) CGFloat frameX;
-(CGFloat)frameX;
-(void)setFrameX:(CGFloat)newX;
#end
#implementation UIView (JCUtilities)
- (CGFloat)frameX {
return self.frame.origin.x;
}
- (void)setFrameX:(CGFloat)newX {
self.frame = CGRectMake(newX, self.frame.origin.y,
self.frame.size.width, self.frame.size.height);
}