remove all subLayers from a view

Question

In an animation I added a lot of sublayers to a view, with:

[self.view.layer addSublayer:layer1];
[self.view.layer addSublayer:layer2];

....

I would like to remove all sublayers with an action. I already tried with this suggestion of a similar question:

rootLayer.sublayers = nil;

but it doesn't work...

Could you help me? Than you!

Joyjoya

Answer 1

The sublayers property of a CALayer object returns a copy of the array. Setting it no nil does nothing about the sublayers. This however will do:

for (CALayer *layer in self.view.layer.sublayers) {
    [layer removeFromSuperlayer];
}

Or, in Swift

self.view.layer.sublayers?.forEach { $0.removeFromSuperlayer() }

Heartsease

It seems I am mistaken. You can set the sublayers to an array prepopulated with CALayer objects. My solution is still correct, though. Also this oneliner should probably work (untested): [self.view.layer.sublayers makeObjectsPerformSelector:@selector(removeFromSuperlayer)] – Heartsease

@SveinHalvorHalvorsen That one line does work. Its much cleaner than a loop – Correspondent

Plus, it's sometimes problematic to mutate an array while iterating through it. Maybe it happens to work here, but in general it can be problematic. – Richman

The sublayers property of CALayer returns a copy. However, so you're not mutating the array you're iterating over. Also, if an element of the array is no longer a sublayer of the layer by the time you call removeFromSuperLayer this has no side-effects unless the layer has been added as a sublayer to another layer. – Heartsease

Although sublayers property of CALayer has "copy" attribute, this code causes crash with more than one sublayer (trying to mutate array while enumerating it). Explicitly copying sublayers array fixes this problem: for (CALayer *sublayer in [rootLayer.sublayers copy]) { [sublayer removeFromSuperlayer]; } – Singlehanded

For swift version,it will be better if we can add check of ---- if layer.isKindOfClass(CAShapeLayer) { layer.removeFromSuperlayer() } – Storied

this threw NSGenericException – Hassan

@JoeBlow I reverted your edits. There is no reason to only remove CAShapeLayer. The original question does not mention shape layers, and this arbitrarily restricts the layers removed to one special kind. We want to remove all sublayers. The code above does not crash, and does not mutate the array while iterating. – Heartsease

Big Thanks for you man, a week pass trying to solve this issue. just with your code everything is okay. – Overbearing

Like we have tag in view is there any specific thing to identify specific layer ? – Victual

Answer 2

Swift 3.0 & Swift 4.0

Set the sublayers property to nil to remove all sublayers from a view.

view.layer.sublayers = nil

also you can add

.removeAll()

Monochrome

Worked for me, Dont know any downside of doing this. Should this be used rather than calling removeFromSuperLayer() for each sub layer? May be others can comment. – Calliope

Answer 3

This worked for me and fixed the crash:

[self.view.layer.sublayers makeObjectsPerformSelector:@selector(removeFromSuperlayer)]

I changed the view with my image UImageview, and the crash is gone.

Jokjakarta

Answer 4

For swift5 to remove CAShapeLayer from added view

guard let sublayers = self.view.layer.sublayers else { return }

for sublayer in sublayers where sublayer.isKind(of: CAShapeLayer.self) {
        sublayer.removeFromSuperlayer()
}

Zurek

Answer 5

Swift 2.0:

    for layer: CALayer in self.view.layer.sublayers! {
        layer.removeFromSuperlayer()
    }

or

    self.view.layer.performSelector("removeFromSuperlayer")

Hopscotch

Answer 6

Swift 5:

You can either remove the layer itself or iterate through them and do the following:

layer.removeAllAnimations()
layer.removeFromSuperlayer()

Cutthroat

Answer 7

Swift 4.1

self.view.layer.sublayers?.removeAll()

or if in a UIView sub-class just

layer.sublayers?.removeAll()

Sunstone

this crashes, any ideas why – Adroit

There's a gotcha here - beware that you didn't create a layer that you then subsequently try to access after removing all sublayers at another place in your code! – Sunstone

Answer 8

If you want to delete all sublayers and add a new one, you can easily do:

rootLayer.sublayers = [layer1] // adding one layer

rootLayer.sublayers = [layer1, layer2, ...] // adding two or more layers

This could be helpful, if you work with tableview or collectionview cells. You don't need to call prepareForReuse for removing the sublayers.

Libidinous