CODEWITHSUNDEEP
iosswiftuitableview
user5899631
user5899631

Reputation:

Another solution instead of tableView.reloadData()

I am calling batch updates(begin/end updates) on a tableView using this code:

  let oldImageSet = Set(oldImageArray)
  let newImageSet = Set(self.images)
  let missingImages = newImageSet.subtracting(oldImageSet)

  let missingImageIndexPaths = Array(missingImages).map{NSIndexPath(row: self.images.index(of: $0)!, section: 0)}
  //Array(missingImages).map{NSIndexPath(forRow:newImageUUIDArray.indexOf($0)!,inSection:1)}

  let removedImages = oldImageSet.subtracting(newImageSet)
  let removedImageIndexPaths = Array(removedImages).map{NSIndexPath(row:oldImageArray.index(of: $0)!,section:0)}

  self.tableView.beginUpdates()
  if missingImageIndexPaths.isEmpty == false {
        self.tableView.insertRows(at: missingImageIndexPaths as [IndexPath],with:.top)
  }

  if removedImageIndexPaths.isEmpty == false {
        self.tableView.deleteRows(at: removedImageIndexPaths as [IndexPath],with:.none)
  }
  self.tableView.endUpdates()

Which is working alright.

Edit

This is my tableView section counts and how I have it set up:

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 55
}

func numberOfSections(in tableView: UITableView) -> Int {

    return posts.count
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 1
}

But now I have another tableView I would like to be able to call this on, But it has 'Sections' so When I use this I get a crash...?

Does anyone know how to use this code on a tableView with sections?

Many thanks in advance!

Upvotes: 1

Views: 176

Answers (2)

beyowulf
beyowulf

Reputation: 15331

You should just apply what you're doing with rows to sections which means changing IndexPaths to IndexSets. IndexSet can be initialized with an array of Ints where each Int represents a corresponding section.

  let oldImageSet = Set(oldImageArray)
  let newImageSet = Set(self.images)
  let addedImages = newImageSet.subtracting(oldImageSet)
  // map each image to the section equivalent to its index in `self.images`
  let addedImageSections = Array(missingImages).map{ self.images.indexOf($0)! }
  let addedImageIndexSet = IndexSet(addedImageSections)

  // repeat above process but in reverse to find images that have been removed
  let removedImages = oldImageSet.subtracting(newImageSet)
  let removedImageSections = Array(removedImages).map{ oldImageArray.index(of: $0)! }
  let removedImageIndexSet = IndexSet(removedImageSections)

  self.tableView.beginUpdates()

  // if images have been added insert new sections 
  if !addedImageIndexSet.isEmpty {
        self.tableView.insertSections(addedImageIndexSet, with: .top)
  }

  // if images have been deleted remove sections    
  if !removedImageIndexSet.isEmpty {
        self.tableView.deleteSections(removedImageIndexSet, with: .none)
  }
  self.tableView.endUpdates()

Upvotes: 0

Sandeep Kumar
Sandeep Kumar

Reputation: 328

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 55
}

func numberOfSections(in tableView: UITableView) -> Int {

    return posts.count
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 1
}

replace code with following code :

func tableView(_ tableView: UITableView, heightForHeaderInSection section: Int) -> CGFloat {
    return 55
}

func numberOfSections(in tableView: UITableView) -> Int {

    return 1
}

func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return posts.count
}

Upvotes: 1

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