crea il pulsante nell'intestazione della sezione tableview float/allinea a destra a livello di codice // Swift

Question

Ho provato ad allineare di float un UIButton a destra nell'intestazione di sezione di un TableView universalmente. Finora ho solo riuscito a aggiungere vincoli per le dimensioni di una schermata ...

Ecco il mio codice finora:

override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? { 
    var headerFrame:CGRect = tableView.frame 

    let titelArr: NSArray = ["1", "2", "3", "4", "5", "6"] 
    var title = UILabel(frame: CGRectMake(10, 10, 100, 30)) 
    title.font = UIFont.boldSystemFontOfSize(20.0) 
    title.text = titelArr.objectAtIndex(section) as? String 
    title.textColor = UIColor.whiteColor() 


    var headBttn:UIButton = UIButton.buttonWithType(UIButtonType.ContactAdd) as UIButton 
    headBttn.frame = CGRectMake(320, 10, 30, 30) 
    headBttn.enabled = true 
    headBttn.titleLabel?.text = title.text 
    headBttn.tag = titelArr.indexOfObject(titelArr.objectAtIndex(section)) 
    headBttn.addTarget(self, action: "addItem:", forControlEvents: UIControlEvents.TouchUpInside) 

    var headerView:UIView = UIView(frame: CGRectMake(0, 0, headerFrame.size.width, headerFrame.size.height)) 
    headerView.backgroundColor = UIColor(red: 108/255, green: 185/255, blue: 0/255, alpha: 0.9) 
    headerView.addSubview(title) 
    headerView.addSubview(headBttn) 

    return headerView 

} 

Come posso fare il tasto destro galleggiante? Il resto dei vincoli può rimanere come sono ...

THX per il vostro aiuto!

// Seb

Answer 1

Thx a @rdelmar e alcune ricerche ecco la risposta se qualcuno deve essere interessavano ;-)

override func tableView(tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? { 
    var headerFrame = tableView.frame 

    var headerView:UIView = UIView(frame: CGRectMake(0, 0, headerFrame.size.width, headerFrame.size.height)) 
    headerView.backgroundColor = UIColor(red: 108/255, green: 185/255, blue: 0/255, alpha: 0.9) 

    var title = UILabel() 
    title.setTranslatesAutoresizingMaskIntoConstraints(false) 
    title.font = UIFont.boldSystemFontOfSize(20.0) 
    title.text = titelArr.objectAtIndex(section) as? String 
    title.textColor = UIColor.whiteColor() 
    headerView.addSubview(title) 

    var headBttn:UIButton = UIButton.buttonWithType(UIButtonType.System) as UIButton 
    headBttn.setTranslatesAutoresizingMaskIntoConstraints(false) 
    headBttn.enabled = true 
    headBttn.titleLabel?.text = title.text 
    headBttn.tag = titelArr.indexOfObject(titelArr.objectAtIndex(section)) 
    headBttn.addTarget(self, action: "addItem:", forControlEvents: UIControlEvents.TouchUpInside) 
    headerView.addSubview(headBttn) 

    var viewsDict = Dictionary <String, UIView>() 
    viewsDict["title"] = title 
    viewsDict["headBttn"] = headBttn 

    headerView.addConstraints(
     NSLayoutConstraint.constraintsWithVisualFormat(
      "H:|-10-[title]-[headBttn]-15-|", options: nil, metrics: nil, views: viewsDict)) 

    headerView.addConstraints(
     NSLayoutConstraint.constraintsWithVisualFormat(
      "V:|-[title]-|", options: nil, metrics: nil, views: viewsDict)) 
    headerView.addConstraints(
     NSLayoutConstraint.constraintsWithVisualFormat(
      "V:|-[headBttn]-|", options: nil, metrics: nil, views: viewsDict)) 

    return headerView 

} 

Answer 2

Thnx per condividere la sorprendente risposta @Seb. Poiché ci sono state alcune modifiche apportate in Swift, che influisce sulla tua risposta. Fornirò un esempio di come fare lo stesso in Swift 3 e 4:

func tableView(_ tableView: UITableView, viewForHeaderInSection section: Int) -> UIView? { 
    let headerView = UIView(frame: CGRect(x: 0, y: 0, width: tableView.frame.size.width, height: tableView.frame.size.height)) 
    headerView.backgroundColor = UIColor.lightGray 

    let title = UILabel() 
    title.translatesAutoresizingMaskIntoConstraints = false 
    title.text = "myTitle" 
    headerView.addSubview(title) 

    let button = UIButton(type: .system) 
    button.translatesAutoresizingMaskIntoConstraints = false 
    button.setTitle("myButton", for: .normal) 
    headerView.addSubview(button) 

    var headerViews = Dictionary<String, UIView>() 
    headerViews["title"] = title 
    headerViews["button"] = button 

    headerView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "H:|-10-[title]-[button]-15-|", options: [], metrics: nil, views: headerViews)) 
    headerView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-[title]-|", options: [], metrics: nil, views: headerViews)) 
    headerView.addConstraints(NSLayoutConstraint.constraints(withVisualFormat: "V:|-[button]-|", options: [], metrics: nil, views: headerViews)) 

    return headerView 
}