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Extention for dismissKeyboard

extension UIViewController {

   func hideKeyboardWhenTappedAround() {

       let tap: UITapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(UIViewController.dismissKeyboard))

       tap.cancelsTouchesInView = false

       view.addGestureRecognizer(tap)

   }

   func dismissKeyboard() {

       view.endEditing(true)

   }

}

[djangofreeeman-blog]

Appdelegate

let ad = UIApplication.shared.delegate as! AppDelegate

let context = ad.persistentContainer.viewContext

Save

       let store = Store(context: context)

       store.name = "Amazon"

       let store1 = Store(context: context)

       store1.name = "Pchome"

       let store2 = Store(context: context)

       store2.name = "Yahoo"

       let store3 = Store(context: context)

       store3.name = "Asos"

       ad.saveContext()

Fetch

      let fetch : NSFetchRequest<Store> = Store.fetchRequest()

       do {

           self.stores = try context.fetch(fetch)

           self.selector.reloadAllComponents()

       }catch{

       //Handle error

       }

-----------------------With table view

#PREPARE

UITableViewDelegate,UITableViewDataSource,NSFetchedResultsControllerDelegate

func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {       tableView.beginUpdates() 

 }

func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {       tableView.endUpdates()

 }

func controller(_ controller: NSFetchedResultsController<NSFetchRequestResult>, didChange anObject: Any, at indexPath: IndexPath?, for type: NSFetchedResultsChangeType, newIndexPath: IndexPath?) {

       switch type {

       case .insert:

           if let indexPath = newIndexPath{

               tableView.insertRows(at: [indexPath], with: .fade)

           }

           break

       case .delete :

           if let indexPath = indexPath{

               tableView.deleteRows(at: [indexPath], with: .fade)

           }

           break

       case .update :

           if let indexPath = indexPath{

               let cell = tableView.cellForRow(at: indexPath) as! ItemCell

               ConfigCell(cell: cell, indexPath: indexPath as NSIndexPath)

           }

           break

       case .move :

           if let indexPath = indexPath{

               tableView.deleteRows(at: [indexPath], with: .fade)

           }

           if let indexPath = newIndexPath{

               tableView.insertRows(at: [indexPath], with: .fade)

           }

           break

       }

   }

------FETCH

      let fetchRequest : NSFetchRequest<Item> = Item.fetchRequest()

       let dateSort = NSSortDescriptor(key: "created", ascending: false)

       fetchRequest.sortDescriptors = [dateSort]

       let controller  = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)

       self.controller = controller

       do{

           try controller.performFetch()

       }catch{

           let error = error as! NSError

           print("\(error)")

       }

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My first brew list

[djangofreeeman-blog]

Carousel like home screen

這種特效是如何做的呢在這邊紀錄一下

基本上他是個CollectionView

只是把ScrollDirection改成Horzontal

接下來就像TableView一樣把Cell 跟custom class 做出來

Cell 圓邊的部分在這裡

override func layoutSubviews() {

       super.layoutSubviews()

       self.layer.cornerRadius = 15.0

       self.clipsToBounds = true

   }

接下來把Collection View Controller 加入 DataSource

extension HomeViewController : UICollectionViewDataSource {

   func numberOfSections(in collectionView: UICollectionView) -> Int {

       return 1

   }

   func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {

       return 2

   }

   func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {

       let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "Interest Cell", for: indexPath) as! UIViewCollectionCellCollectionViewCell

       cell.interest = self.interests[indexPath.item]

       return cell

   }

}

把上方的狀態欄改成白色

override var preferredStatusBarStyle: UIStatusBarStyle {

       return .lightContent

   }

加入UIScrollViewDelegate

最後為了有更好地划動體驗滑的時候會照著index 滑不會會不上不下

因為CollectionViewController 是 ScrollView 所以是UIScrollViewDelegate

extension HomeViewController : UIScrollViewDelegate {

   func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {

       //取得Layout

       let layout = self.collectionView?.collectionViewLayout as! UICollectionViewFlowLayout

       //計算Cell的寬度

       let cellWidthIncludingSpacing = layout.itemSize.width + layout.minimumLineSpacing

       var offset = targetContentOffset.pointee

       //算出現在顯示出的Cell index

       let index = (offset.x + scrollView.contentInset.left) / cellWidthIncludingSpacing

       let roundIndex = round(index)

       offset = CGPoint(x: roundIndex * cellWidthIncludingSpacing - scrollView.contentInset.left, y: -scrollView.contentInset.top)

       targetContentOffset.pointee = offset

   }

}

[djangofreeeman-blog]

UIImageView extention “URL download”

從網路上下載圖片下來放入你的ImageView

使用：

extension UIImageView {

   func downloadedFrom(url: URL, contentMode mode: UIViewContentMode = .scaleAspectFit) {

       contentMode = mode

       URLSession.shared.dataTask(with: url) { (data, response, error) in

           guard let httpURLResponse = response as? HTTPURLResponse, httpURLResponse.statusCode == 200,

               let mimeType = response?.mimeType, mimeType.hasPrefix("image"),

               let data = data, error == nil,

               let image = UIImage(data: data)

               else { return }

           DispatchQueue.main.async() { () -> Void in

               self.image = image

           }

           }.resume()

   }

   func downloadedFrom(link: String, contentMode mode: UIViewContentMode = .scaleAspectFit) {

       guard let url = URL(string: link) else { return }

       downloadedFrom(url: url, contentMode: mode)

   }

}