访问自定义标题视图的组件

Question

A custom header class is created for the header, view using xib. Trying to get the value of UITextField from that header class. Below is the code:

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {

    let customHeaderView = Bundle.main.loadNibNamed("AddHeaderTableViewCell", owner: self, options: nil)?.last as! AddHeaderTableViewCell

customHeaderView.txtFieldAdd.placeholder = ""
return customHeaderView
}

When trying to get value from the textfields below:

 @objc func addMoreToMytask(sender: UIButton!) {

   isAddStep = false

    let header = tblAddedTasks.headerView(forSection: 0) as? AddHeaderTableViewCell
    let sectionTitle = header?.textLabel?.text

    arrAdded.append((header?.txtFieldAdd.text!)!)
    tblAddedTasks.reloadData()
}

It is giving error in this line

let header = tblAddedTasks.headerView(forSection: 0) as? AddHeaderTableViewCell

Gives warning and crash when run

Cast from 'UITableViewHeaderFooterView?' to unrelated type 'AddHeaderTableViewCell' always fails

Please guide for the same.

Answer 1

You may try using the header object as a member.

var customHeaderView : AddHeaderTableViewCell = nil
func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? {
  customHeaderView = Bundle.main.loadNibNamed("AddHeaderTableViewCell", owner: self, options: nil)?.last as! AddHeaderTableViewCell
  customHeaderView.txtFieldAdd.placeholder = ""
  return customHeaderView
}

And then you can use the member object;

@objc func addMoreToMytask(sender: UIButton!) {

    isAddStep = false

    // let header = tblAddedTasks.headerView(forSection: 0) as? AddHeaderTableViewCell
    // let sectionTitle = header?.textLabel?.text
    let sectionTitle = customHeaderView.textLabel?.text 

    arrAdded.append((customHeaderView.txtFieldAdd.text!)!)
    tblAddedTasks.reloadData()
}

I m not sure but the reason may optional value. Tableview only renders view on the screen, you may getting nil. Signature of the function is;

func headerView(forSection section: Int) -> UITableViewHeaderFooterView?

It returns an optional variable. You trying to cast an optional variable. XCode may not work perfectly on casting optional variables, so it can't warn you with enough info.

You may try;

tblAddedTasks.headerView(forSection: 0) as! AddHeaderTableViewCell

or

tblAddedTasks.headerView(forSection: 0)! as?  AddHeaderTableViewCell

Probably will crash but at least you will see the real reason for crashing.