Swift 4 ERROR: Cannot assign to value: 'btn' is a 'let' constant





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I am trying to create code that woud return background image of a button on UICollectionView inside UITableView. Here is the code:



func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: 

"InsideCollectionViewCell", for: indexPath) as! InsideCollectionViewCell



    if let btn = cell.viewWithTag(100) as? UIButton {

        btn = collectionPics[indexPath.row]

    }



    return cell

}





ios swift swift4







share|improve this question

























  • Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

    – Paulw11
    Nov 22 '18 at 4:52











  • Show how collectionPics is declared please.

    – matt
    Nov 22 '18 at 5:03











  • Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

    – CPR
    Nov 22 '18 at 11:47


















-5















I am trying to create code that woud return background image of a button on UICollectionView inside UITableView. Here is the code:



func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: 

"InsideCollectionViewCell", for: indexPath) as! InsideCollectionViewCell



    if let btn = cell.viewWithTag(100) as? UIButton {

        btn = collectionPics[indexPath.row]

    }



    return cell

}





ios swift swift4







share|improve this question

























  • Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

    – Paulw11
    Nov 22 '18 at 4:52











  • Show how collectionPics is declared please.

    – matt
    Nov 22 '18 at 5:03











  • Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

    – CPR
    Nov 22 '18 at 11:47














-5












-5








-5








I am trying to create code that woud return background image of a button on UICollectionView inside UITableView. Here is the code:



func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: 

"InsideCollectionViewCell", for: indexPath) as! InsideCollectionViewCell



    if let btn = cell.viewWithTag(100) as? UIButton {

        btn = collectionPics[indexPath.row]

    }



    return cell

}





ios swift swift4







share|improve this question
















I am trying to create code that woud return background image of a button on UICollectionView inside UITableView. Here is the code:



func collectionView(_ collectionView: UICollectionView, cellForItemAt 

indexPath: IndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: 

"InsideCollectionViewCell", for: indexPath) as! InsideCollectionViewCell



    if let btn = cell.viewWithTag(100) as? UIButton {

        btn = collectionPics[indexPath.row]

    }



    return cell

}





ios swift swift4




ios swift swift4






share|improve this question















share|improve this question













share|improve this question




share|improve this question








edited Nov 22 '18 at 7:36









Damon

5361619




5361619










asked Nov 22 '18 at 3:17









Jm JarkassJm Jarkass

15




15













  • Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

    – Paulw11
    Nov 22 '18 at 4:52











  • Show how collectionPics is declared please.

    – matt
    Nov 22 '18 at 5:03











  • Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

    – CPR
    Nov 22 '18 at 11:47



















  • Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

    – Paulw11
    Nov 22 '18 at 4:52











  • Show how collectionPics is declared please.

    – matt
    Nov 22 '18 at 5:03











  • Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

    – CPR
    Nov 22 '18 at 11:47

















Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

– Paulw11
Nov 22 '18 at 4:52





Don't use tags to obtain your views. Create properties in your cell subclass and then you can access them directly

– Paulw11
Nov 22 '18 at 4:52













Show how collectionPics is declared please.

– matt
Nov 22 '18 at 5:03





Show how collectionPics is declared please.

– matt
Nov 22 '18 at 5:03













Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

– CPR
Nov 22 '18 at 11:47





Friendly advice: you could improve this question by giving it a better title. The error message you are receiving from the compiler is very descriptive, and tells you exactly how to solve the problem (btn is a let constant -> yet, you are trying to reassign btn to an item from your collectionPics collection.). A better question would be "How can I set the background image on a button in a UICollectionView?". Also, you haven't actually asked a question in your description; you have merely stated facts. It's very hard to answer a question when no question was actually asked :)

– CPR
Nov 22 '18 at 11:47












1 Answer
1






active

oldest

votes


















2














It looks like you're trying to set the image within a collection view cell. Assuming that:




  • collectionPics : [UIImage]

  • btn is set correctly


then you can replace



btn = collectionPics[indexPath.row]


With (edit: for background image)



btn.setBackgroundImage(collectionPics[indexPath.row], for: .normal)





share|improve this answer


























  • Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

    – Jm Jarkass
    Nov 22 '18 at 3:34











  • I tried that already but it still does not work :(

    – Jm Jarkass
    Nov 22 '18 at 3:52











  • What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

    – matt
    Nov 22 '18 at 5:03












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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









2














It looks like you're trying to set the image within a collection view cell. Assuming that:




  • collectionPics : [UIImage]

  • btn is set correctly


then you can replace



btn = collectionPics[indexPath.row]


With (edit: for background image)



btn.setBackgroundImage(collectionPics[indexPath.row], for: .normal)





share|improve this answer


























  • Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

    – Jm Jarkass
    Nov 22 '18 at 3:34











  • I tried that already but it still does not work :(

    – Jm Jarkass
    Nov 22 '18 at 3:52











  • What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

    – matt
    Nov 22 '18 at 5:03
















2














It looks like you're trying to set the image within a collection view cell. Assuming that:




  • collectionPics : [UIImage]

  • btn is set correctly


then you can replace



btn = collectionPics[indexPath.row]


With (edit: for background image)



btn.setBackgroundImage(collectionPics[indexPath.row], for: .normal)





share|improve this answer


























  • Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

    – Jm Jarkass
    Nov 22 '18 at 3:34











  • I tried that already but it still does not work :(

    – Jm Jarkass
    Nov 22 '18 at 3:52











  • What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

    – matt
    Nov 22 '18 at 5:03














2












2








2







It looks like you're trying to set the image within a collection view cell. Assuming that:




  • collectionPics : [UIImage]

  • btn is set correctly


then you can replace



btn = collectionPics[indexPath.row]


With (edit: for background image)



btn.setBackgroundImage(collectionPics[indexPath.row], for: .normal)





share|improve this answer















It looks like you're trying to set the image within a collection view cell. Assuming that:




  • collectionPics : [UIImage]

  • btn is set correctly


then you can replace



btn = collectionPics[indexPath.row]


With (edit: for background image)



btn.setBackgroundImage(collectionPics[indexPath.row], for: .normal)






share|improve this answer














share|improve this answer



share|improve this answer








edited Nov 22 '18 at 3:40

























answered Nov 22 '18 at 3:27









Chris ShawChris Shaw

51848




51848













  • Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

    – Jm Jarkass
    Nov 22 '18 at 3:34











  • I tried that already but it still does not work :(

    – Jm Jarkass
    Nov 22 '18 at 3:52











  • What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

    – matt
    Nov 22 '18 at 5:03



















  • Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

    – Jm Jarkass
    Nov 22 '18 at 3:34











  • I tried that already but it still does not work :(

    – Jm Jarkass
    Nov 22 '18 at 3:52











  • What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

    – matt
    Nov 22 '18 at 5:03

















Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

– Jm Jarkass
Nov 22 '18 at 3:34





Hi, thank you, but I forgot to mention that the image I'm trying to set is of a buttons background image??

– Jm Jarkass
Nov 22 '18 at 3:34













I tried that already but it still does not work :(

– Jm Jarkass
Nov 22 '18 at 3:52





I tried that already but it still does not work :(

– Jm Jarkass
Nov 22 '18 at 3:52













What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

– matt
Nov 22 '18 at 5:03





What "does not work"? You asked how to avoid a compilation error and this answer tells you how to avoid that error.

– matt
Nov 22 '18 at 5:03




















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