how to remove subviews from scrollview?

Question

how do i remove all subviews from my scrollview...

i have a uiview and a button above it in the scrollview something like this....

here is my code to add sub

Answer 1

The best and easiest is to use

for(UIView *subview in [scrollView subviews])
{
  [subview removeFromSuperview];
}

This indeed causes crash as the basic rule is array shouldn't modified while being enumerated, to prevent that we can use

[[scrollView subviews] 
           makeObjectsPerformSelector:@selector(removeFromSuperview)];

But sometimes crash is still appearing because makeObjectsPerformSelector: will enumerate and performs selector, Also in iOS 7 ui operations are optimized to perform more faster than in iOS 6, Hence the best way to iterate array reversely and remove

NSArray *vs=[scrollView subviews];
for(int i=vs.count-1;i>=0;i--)
{
    [((UIView*)[vs objectAtIndex:i]) removeFromSuperview];
}

Note : enumerating harms modification but not iterating...

Answer 2

The problem with the UIScrollView and others subclass of UIView is that they contains initially some views (like the vertical and horizontal scrollbar for the UIScrollView). So i created a category of UIView to delete the Subviews filtered on the class.

For example:

[UIScrollView removeAllSubviewsOfClass:[FooView class],[BarView class],nil];

The code:

- (void)removeAllSubviewsOfClass:(Class)firstClass, ... NS_REQUIRES_NIL_TERMINATION;


- (void)removeAllSubviewsOfClass:(Class)firstClass, ...
{
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"FALSEPREDICATE"];

    va_list args;
    va_start(args, firstClass);

    for (Class class = firstClass; class != nil; class = va_arg(args, Class)) 
    {
        predicate = [NSCompoundPredicate orPredicateWithSubpredicates:[NSArray arrayWithObjects:predicate,[NSPredicate predicateWithFormat:@"self isKindOfClass:%@",class], nil]];
    }

    va_end(args);
    [[self.subviews filteredArrayUsingPredicate:predicate] makeObjectsPerformSelector:@selector(removeFromSuperview)];

}

Answer 3

To add to what Tim said, I noticed that you are tagging your views. If you wanted to remove a view with a certain tag you could use:

[[myScrollView viewWithTag:myButtonTag] removeFromSuperview];

Answer 4

An old question; but as it's the first hit on Google for this I thought I'd also make a note that there's also this method:

[[myScrollView subviews] makeObjectsPerformSelector:@selector(removeFromSuperview)];

You can't do the isKindOfClass check with this, but it's still a good solution to know about.

Edit: Another point to note is that the scrollbar of a scrollview is added as a subview to that scrollview. Thus if you iterate through all the subviews of a scrollview you will come across it. If removed it'll add itself again - but it's important to know this if you're only expecting your own UIView subclasses to be in there.

Amendment for Swift 3:

myScrollView.subviews.forEach { $0.removeFromSuperview() }

Answer 5

I don't think you should use the fast enumeration suggestion.

for(UIView *subview in [view subviews]) {
   [subview removeFromSuperview];
}

Isn't this supposed to throw an exception if you change the collection being iterated? http://developer.apple.com/library/ios/#documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocFastEnumeration.html#//apple_ref/doc/uid/TP30001163-CH18-SW3

This example may be better.

NSArray *subviews = [[scroller subviews] copy];
for (UIView *subview in subviews) {
    [subview removeFromSuperview];
}
[subviews release];

Answer 6

for(subview) in self.scrollView.subviews {
        subview.removeFromSuperview()
}