Background color about parchment HOT 12 CLOSED

There is no built in option for defining this, but you can achieve it pretty easily by subclassing PagingCell and setting the background color based on the selected state. Just create your own subclass and override setPagingItem:

class CustomPagingCell: PagingTitleCell {
  
  override func setPagingItem(_ pagingItem: PagingItem, selected: Bool, theme: PagingTheme) {
    super.setPagingItem(pagingItem, selected: selected, theme: theme)
    
    if selected {
      contentView.backgroundColor = .red
    } else {
      contentView.backgroundColor = .white
    }
}

Then set the menuItemClass property to CustomPagingCell.self:

struct Options: PagingOptions {
  let menuItemClass: PagingCell.Type = CustomPagingCell.self
}

And pass that into the PagingViewController:

FixedPagingViewController(viewControllers: viewControllers, options: Options())

This will set the background color when the selected state changes, without any animation. If you want to tween between the colors based on how much the user has scrolled, you can override apply:layoutAttributes instead of setPagingItem:

class CustomPagingCell: PagingTitleCell {
 
  open override func apply(_ layoutAttributes: UICollectionViewLayoutAttributes) {
    super.apply(layoutAttributes)
    if let attributes = layoutAttributes as? PagingCellLayoutAttributes {
      contentView.backgroundColor = UIColor.interpolate(
        from: .white,
        to: .red,
        with: attributes.progress)
    }
  }
  
}

This will interpolate between the selected background color based on the scroll progress. I'm using UIColor.interpolate here which you can find the source code for inUIColor+interpolation.swift.

from parchment.

huum thanks, one more question, oh i get click on menu cell?

from parchment.

If you are using FixedPagingViewController you can use the FixedPagingViewControllerDelegate to get notified when an item was scrolled to:

public protocol FixedPagingViewControllerDelegate : class {
  func fixedPagingViewController(fixedPagingViewController: FixedPagingViewController, willScrollToItem: ViewControllerItem, atIndex index: Int)
  func fixedPagingViewController(fixedPagingViewController: FixedPagingViewController, didScrollToItem: ViewControllerItem, atIndex index: Int)
}

Or if you need the actual select event you create your own subclass and override didSelectItem:

class MyPagingViewController: FixedPagingViewController {
  override public func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    super.collectionView(collectionView, didSelectItemAt: indexPath)
    print("did select")
  }
}

from parchment.

class ViewController: UIViewController {

override func viewDidLoad() {
super.viewDidLoad()

let storyboard = UIStoryboard(name: "Main", bundle: nil)
let firstViewController = storyboard.instantiateViewController(withIdentifier: "FirstViewController")
let secondViewController = storyboard.instantiateViewController(withIdentifier: "SecondViewController")


let pagingViewController = FixedPagingViewController(viewControllers: [
  firstViewController,
  secondViewController
])



addChildViewController(pagingViewController)
view.addSubview(pagingViewController.view)
view.constrainToEdges(pagingViewController.view)
pagingViewController.didMove(toParentViewController: self)

}
}

sorry for my poor knowledge, but in a class like this how I create mine subclass and override didselectitem?

from parchment.

You need to create a new class outside ViewController – like the MyPagingViewController snippet above – and replace this line:

let pagingViewController = FixedPagingViewController(viewControllers: [

with this:

let pagingViewController = MyPagingViewController(viewControllers: [

from parchment.

thanks for support :)

from parchment.

No problem, happy to help!

from parchment.

hi, its me again..... can u explain me "If you are using FixedPagingViewController you can use the FixedPagingViewControllerDelegate to get notified when an item was scrolled to", i dnt know who to use delegate :/..

from parchment.

No worries, the documentation for this isn't very good. You need to conform to the FixedPagingViewControllerDelegate protocol in you ViewController class. Here an example:

extension ViewController: FixedPagingViewControllerDelegate {

  func fixedPagingViewController(fixedPagingViewController: FixedPagingViewController, willScrollToItem: ViewControllerItem, atIndex index: Int) {
    print("will scroll to item")
  }

  func fixedPagingViewController(fixedPagingViewController: FixedPagingViewController, didScrollToItem: ViewControllerItem, atIndex index: Int) {
     print("did scroll to item")
  }

}

Then set the itemDelegate property in viewDidLoad:

pagingViewController.itemDelegate = self

from parchment.

hi, i think i found a bug, in fixedPageViewController u have :
open override func em_pageViewController(_ pageViewController: EMPageViewController, didFinishScrollingFrom startingViewController: UIViewController?, destinationViewController: UIViewController, transitionSuccessful: Bool) {
super.em_pageViewController(pageViewController, didFinishScrollingFrom: startingViewController, destinationViewController: destinationViewController, transitionSuccessful: transitionSuccessful)

    if let index = items.index(where: { $0.viewController == destinationViewController }) {
        itemDelegate?.fixedPagingViewController(
            fixedPagingViewController: self,
            didScrollToItem: items[index],
            atIndex: index)
    }  
}

i think u need check if transition is successful because if u do a "fake swipe" and dnt swipe to next menu tab and stay on same menu tab and didscroolToItem is activated.... in my opinion the code looks like this:

open override func em_pageViewController(_ pageViewController: EMPageViewController, didFinishScrollingFrom startingViewController: UIViewController?, destinationViewController: UIViewController, transitionSuccessful: Bool) {
super.em_pageViewController(pageViewController, didFinishScrollingFrom: startingViewController, destinationViewController: destinationViewController, transitionSuccessful: transitionSuccessful)
if transitionSuccessful == true {

    if let index = items.index(where: { $0.viewController == destinationViewController }) {
        itemDelegate?.fixedPagingViewController(
            fixedPagingViewController: self,
            didScrollToItem: items[index],
            atIndex: index)
        }

     }
  }

from parchment.

Yeah, that's definitely a bug. I also found another bug were the willScrollItemItem was not called at all. Fixed in #63 – will release a new version soon. Thanks for catching that 🙌

from parchment.

u welcome :)

from parchment.