Iterate over all the UITableCells given a section id

Question

Using Swift, how can I iterate over all the UITableCells given a section id (eg: all cells in section 2)?

I only see this method: tableView.cellForRowAtIndexPath, which returns 1 cell given the absolute index, so it doesn't help.

Is there an elegant and easy way?

Note: I want to set the AccesoryType to None for all of the cells in a section, programatically, say: after a button is clicked, or after something happends (what happends is not relevant for the question)

I have the reference for the UITableView and the index of the section.

Answer 1

You misunderstand how table views work. When you want to change the configuration of cells, you do not modify the cells directly. Instead, you change the data (model) for those cells, and then tell your table view to reload the changed cells.

This is fundamental, and if you are trying to do it another way, it won't work correctly.

You said "I need the array of cells before modifying them…" Same thing applies. You should not store state data in cells. As soon as a user makes a change to a cell you should collect the changes and save it to the model. Cells can scroll off-screen and their settings can be discarded at any time.

@LordZsolt was asking you to show your code because from the questions you're asking it's pretty clear you are going about things the wrong way.

EDIT:

If you are convinced that you need to iterate through the cells in a section then you can ask the table view for the number of rows in the target section, then you can loop from 0 to rows-1, asking the table view for each cell in turn using the UITableView cellForRowAtIndexPath method (which is different than the similarly-named data source method.) That method will give you cells that are currently visible on the screen. You can then make changes to those cells.

Note that this will only give you the cells that are currently on-screen. If there are other cells in your target section that are currently not visible those cells don't currently exist, and if the user scrolls, some of those cells might be created. For this reason you will need to save some sort of state information to your model so that when you set up cells from the target section in your datasource tableView:cellForRowAtIndexPath: method you can set them up correctly.

Answer 2

Im using same way of iterating all table view cells , but this code worked for only visible cells , so I'v just add one line allows iterating all table view cells wether visible they are or not

   //get section of interest i.e: first section (0)
       for (var row = 0; row < tableView.numberOfRowsInSection(0); row++)
       {

        var indexPath = NSIndexPath(forRow: row, inSection: 0)

            println("row")
            println(row)
    //following line of code is for invisible cells
        tableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Top, animated: false)


    //get cell for current row as my custom cell i.e :roomCell

            var cell :roomCell = tableView.cellForRowAtIndexPath(indexPath) as roomCell
      }

* the idea is to scroll tableview to every row I'm receiving in the loop so, in every turn my current row is visible ->all table view rows are now visible :D

Answer 3

For Swift 4 I have been using something along the lines of the following and it seems to work pretty well.

for section in 0...self.tableView.numberOfSections - 1 {
            for row in 0...self.tableView.numberOfRows(inSection: section) - 1 {
                let cell = self.tableView.cellForRow(at: NSIndexPath(row: row, section: section) as IndexPath)

                print("Section: \(section)  Row: \(row)")

            }
        }

Answer 4

To answer my own question: "how can I iterate over all the UITableCells given a section id?":

To iterate over all the UITableCells of a section section one must use two methods:

• tableView.numberOfRowsInSection(section)
• tableView.cellForRowAtIndexPath(NSIndexPath(forRow: row, inSection: section))

So the iteration goes like this:

// Iterate over all the rows of a section
for (var row = 0; row < tableView.numberOfRowsInSection(section); row++) {
    var cell:Cell = tableView.cellForRowAtIndexPath(NSIndexPath(forRow: row, inSection: section))?

   // do something with the cell here.
}

At the end of my question, I also wrote a note: "Note: I want to set the AccesoryType to None for all of the cells in a section, programatically". Notice that this is a note, not the question.

I ended up doing that like this:

// Uncheck everything in section 'section'
for (var row = 0; row < tableView.numberOfRowsInSection(section); row++) {
    tableView.cellForRowAtIndexPath(NSIndexPath(forRow: row, inSection: section))?.accessoryType = UITableViewCellAccessoryType.None
}

If there is a more elegant solution, go ahead and post it.

Note: My table uses static data.

Answer 5

Im using this way of iterating all table view cells , but this code worked for only visible cells , so I'v just add one line allows iterating all table view cells wether visible they are or not

  //get section of interest i.e: first section (0)
   for (var row = 0; row < tableView.numberOfRowsInSection(0); row++)
   {

    var indexPath = NSIndexPath(forRow: row, inSection: 0)

        println("row")
        println(row)
//following line of code is for invisible cells
    tableView.scrollToRowAtIndexPath(indexPath, atScrollPosition: UITableViewScrollPosition.Top, animated: false)


//get cell for current row as my custom cell i.e :roomCell

        var cell :roomCell = tableView.cellForRowAtIndexPath(indexPath) as roomCell
  }

* the idea is to scroll tableview to every row I'm receiving in the loop so, in every turn my current row is visible ->all table view rows are now visible

Answer 6

Swift 4

More "swifty", than previous answers. I'm sure this can be done strictly with functional programming. If i had 5 more minutes id do it with .reduce instead. ✌️

func cells(tableView:UITableView) -> [UITableViewCell]{
    var cells:[UITableViewCell] = []
    (0..<tableView.numberOfSections).indices.forEach { sectionIndex in
        (0..<tableView.numberOfRows(inSection: sectionIndex)).indices.forEach { rowIndex in
            if let cell:UITableViewCell = tableView.cellForRow(at: IndexPath(row: rowIndex, section: sectionIndex)) {
                cells.append(cell)
            }
        }
    }
    return cells
}

Answer 7

You can use reloadSections(_:withRowAnimation:) method of UITableView.

This will reload all the cells in the specified sections by calling cellForRowAtIndexPath(_:). Inside that method, you can do whatever you want to those cells.

In your case, you can apply your logic for setting the appropriate accessory type:

if (self.shouldHideAccessoryViewForCellInSection(indexPath.section)) {
    cell.accessoryType = UITableViewCellAccessoryTypeNone
}