How to check if a UIView is a subview of a parent view

Question

I have an app which I add a subview to (and remove the same subview based on user interactions). I am looking for a way to check whether the subview is present or not at any given time.

For example:

In the current view (UIView *viewA) I add a subview (UIView *viewB). I then want a way of checking whether viewB is being displayed at any given time.

Sorry if this isn't very clear, it's quite hard to describe.

score 44 · Accepted Answer · answered Oct 16 '11 at 19:59

44

an UIView stores its superview and is accessible with the superview-property just try

if([viewB superview]!=nil)
    NSLog(@"visible");
else
    NSLog(@"not visible");

But the better approach is to use the hidden-property of UIView

answered Oct 16 '11 at 19:59

thomas

5,637
2
24
35

score 17 · Answer 2 · answered Aug 04 '15 at 20:03

17

I went through the same issue and consulted Apple Documentation and came up with this elegant solution:

if([self.childView isDescendantOfView:self.parentView])
{
    // The childView is contained in the parentView.
}

answered Aug 04 '15 at 20:03

Shinnyx

2,144
2
14
21

score 4 · Answer 3 · answered Mar 22 '18 at 07:37

I updated to Swift4, Thanks a lot to @Shinnyx and @thomas.

if viewB.superview != nil{     
    print("visible")
}
else{
   print("not visible")
}

if selfView.isDescendant(of: self.parentView) {
    print("visible")
}
else{
    print("not visible")
}

func isDescendant(of: UIView)

Returns a Boolean value indicating whether the receiver is a subview of a given view or identical to that view.

score 2 · Answer 4 · edited Jun 20 '12 at 08:57

Here's a method I put in the appDelegate so that I can display the entire subview hierarchy from any point.

// useful debugging method - send it a view and it will log all subviews
// can be called from the debugger
- (void) viewAllSubviews:(UIView *) topView Indent:(NSString *) indent  {
    for (UIView * theView in [topView subviews]){
        NSLog(@"%@%@", indent, theView);
        if ([theView subviews] != nil)
            [self viewAllSubviews:theView Indent: [NSString stringWithFormat:@"%@ ",indent]];
    }
}

call it with a string with one character and it will indent for you. (i.e. [appDelegate viewAllSubviews:self.view Indent:@" "];)

I find it useful to clear the debug pane first, then call this from the debugger, and copy it into a text editor like BBEdit that will show the indents.

You can call it using the mainWindow's view and see everything on your screen.

You can do this in the Xcode debugger with any view using `recursiveDescription` via `po [view recursiveDescription]` — Reid Ellis, Oct 20 '15 at 18:38

How to check if a UIView is a subview of a parent view

4 Answers4