Question

I am having a problem! When I use addSubview: and add a view to a UIScrollView, it adds a completely new view.

I want to either:

• toggle between 3 predefined views, or
• remove the last view from the UIScrollView before adding another one.

(All 3 views have some images so I’d imagine that the second option would be more efficient, memory-wise. However, perhaps the first option would be better on battery life? This is a ‘subquestion’.)

How does one accomplish this?

Answer 1

You could accomplish your plan B by using removeFromSuperview function of your UIView.

Use it as below.

[mySecondImageView removeFromSuperview];
[myScrollView addSubview:myThirdImageView];

EDITED:

When you create UIImageView assign a tag value to each and also use and integer iVar to hold the tag value of your current view lets say it’s currentViewTag ;

myFirstImageView.tag = 1;
mySecondImageView.tag = 2;
myThirdImageView.tag = 3;

currentViewTag = 1;
[myScrollView addSubview:myFirstImageView];

Now use as below

[[myScrollView viewWithTag:currentViewTag] removeFromSuperview];
[myScrollView addSubview:myThirdImageView];
currentViewTag = 3;