CODEWITHSUNDEEP
objective-cioscalayer
abe
abe

Reputation: 4136

Check if a CALayer is already added as a sublayer

I have 5 CALayers each one is a property. Say I added 3 of them as subviews. I need to ba able to chk if one of the layers is already added to the layer.

Upvotes: 14

Views: 13015

Answers (6)

HTron
HTron

Reputation: 366

XCode 11 - Swift 5

if view.layer.sublayers == nil {

    // add Sublayer

}

Upvotes: 1

Lance Samaria
Lance Samaria

Reputation: 19602

I needed to check to see if a gradientLayer was a subLayer of another view. It was the only layer in there so I didn't have to check for anything else. The answers above didn't work for me.

I came across this answer and even though it was used for a different reason it was an easy way to check if the gradientLayer was a child of another view's layer property (the parentLayer) and it works fine for me:

if let _ = (yourParentView.layer.sublayers?.compactMap { $0 as? CAGradientLayer })?.first {

    print("the gradientLayer IS already a subLayer of this parentView's layer property")
} else {

    print("the gradientLayer IS NOT a subLayer of this parentView's layer property")
}

Upvotes: 3

Iya
Iya

Reputation: 1918

  • //to check CALayer Contains Sublayer(shpapelayer/textlayer)

                               if myShapeLayer.sublayers?.count>0
                           {
                               var arr:NSArray? = myShapeLayer.sublayers as NSArray
                               var i:Int=0
                               for i in 0..<arr!.count
                               {
                                   var a: AnyObject = arr!.objectAtIndex(i)
                                   if a.isKindOfClass(CAShapeLayer) || a.isKindOfClass(CATextLayer)
                                   {
                                       if a.isKindOfClass(CAShapeLayer)
                                       {
                                           a = a as! CAShapeLayer

                                           if CGPathContainsPoint(a.path, nil, pointOfCircle, true)
                                           {
                                               NSLog("contains shape layer")

                                           }
                                           else
                                           {
                                               NSLog("not  contains shape layer")

                                           }
                                       }
                                       if a.isKindOfClass(CATextLayer)
                                       {
                                           a = a as! CATextLayer
                                           var fr:CGRect = a.frame as CGRect
                                           if CGRectContainsPoint(fr, pointOfCircle)
                                           {
                                               NSLog("contains textlayer")

                                           }
                                           else
                                           {
                                               NSLog("not contains textlayer")

                                           }
                                       }

                                   }
                               }
                           }

Upvotes: 0

Alberto Lopez
Alberto Lopez

Reputation: 247

view.layer.sublayers gives you an array of the sub layers, to see if your layer was added you can do something like view.layer.sublayers.count and once the layer count reaches what you expect dont add more for ex.

if (view.layer.sublayers.count  < 3) {
//add layer
}else{
// do nothing because the layer has already been added.
}

You can also examine each layer in the sublayer array to better identify the layer you are looking for. Since they are properties you should be able to do a comparison to each of the layers in the array to see if the layer you are looking for has been added.

Upvotes: 6

Ole Begemann
Ole Begemann

Reputation: 135558

if (layer.superlayer == parentLayer) {
    ...
} else {
    ...
}

Upvotes: 8

adig
adig

Reputation: 4057

Have you tried the superlayer property ? It should be nil if your layer isn't added anywhere.

Upvotes: 20

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