The proposed offset is where the collection view would stop without our intervention. We peek into this area by finding its centre as proposedContentOffsetCenterX and examine our currently visible cells to see which one’s centre is closer to the centre of that area.
import UIKit
class CenterCellCollectionViewFlowLayout: UICollectionViewFlowLayout {
var mostRecentOffset : CGPoint = CGPoint()
| // Created by Vasily Ulianov on 09.02.17, updated in 2019. | |
| // License: MIT | |
| import Foundation | |
| /// Subclass of `Operation` that adds support of asynchronous operations. | |
| /// 1. Call `super.main()` when override `main` method. | |
| /// 2. When operation is finished or cancelled set `state = .finished` or `finish()` | |
| open class AsynchronousOperation: Operation { | |
| public override var isAsynchronous: Bool { |
| /** | |
| * Created by kientux on 3/20/15 | |
| */ | |
| import android.util.Base64; | |
| import java.security.MessageDigest; | |
| import java.security.NoSuchAlgorithmException; | |
| import java.security.SecureRandom; | |
| import java.util.Arrays; |
(by @andrestaltz)
If you prefer to watch video tutorials with live-coding, then check out this series I recorded with the same contents as in this article: Egghead.io - Introduction to Reactive Programming.
| import android.content.Context; | |
| import android.graphics.Matrix; | |
| import android.util.AttributeSet; | |
| import android.widget.ImageView; | |
| /** | |
| * ImageView that scales like centerCrop, but instead of showing the centre of the image, it shows the top. | |
| */ | |
| public class TopCropImageView extends ImageView { | |
| public TopCropImageView(Context context) { |
| i386 : iPhone Simulator | |
| x86_64 : iPhone Simulator | |
| arm64 : iPhone Simulator | |
| iPhone1,1 : iPhone | |
| iPhone1,2 : iPhone 3G | |
| iPhone2,1 : iPhone 3GS | |
| iPhone3,1 : iPhone 4 | |
| iPhone3,2 : iPhone 4 GSM Rev A | |
| iPhone3,3 : iPhone 4 CDMA | |
| iPhone4,1 : iPhone 4S |
| - (void)addShadowWithColor:(UIColor *)color alpha:(CGFloat)alpha radius:(CGFloat)radius offset:(CGSize)offset | |
| { | |
| self.layer.shadowOpacity = alpha; | |
| self.layer.shadowRadius = radius; | |
| self.layer.shadowOffset = offset; | |
| if (color) | |
| { | |
| self.layer.shadowColor = [color CGColor]; | |
| } |