Adding UIViewcontrollers to UIScrollview

Adding UIViewcontrollers to UIScrollview

I am changing the layout of an existing application. There are a series of
view which now needs to be added to a scrollview that the users can swipe
to move to next screen. I have added the controllers to scrollview using
the code below.
This code is added in the viewDidLoad of the Viewcontroller which holds
the UIScrolliew
..
int i=1;
int width = 0,height=0;
for(POTCTask *task in [CommonData tasks])
{
UIViewController<TaskViewController> *controller = [TaskViewFactory
getTaskViewController:(task.inputTypeId)];
width = controller.view.frame.size.width;
height = controller.view.frame.size.height;
controller.view.frame = CGRectMake(width*(i-1), 0, width, height);
[self.scrollView addSubview:controller.view];
i++;
}
self.scrollView.contentSize = CGSizeMake(width*i, height);
It loads all view fine. But only the viewDidLoad is getting called in each
viewcontroller. No other methods are getting called And some have
UItableviews in it. But its showing only the first cell.
How can I do this properly in ios?
Thanks