Linh Vo dlsolution

ANNOUNCEMENT

I have moved this over to the Tech Interview Cheat Sheet Repo and has been expanded and even has code challenges you can run and practice against!

The below is just for some preservation for those who stumble across here, but is no longer kept up to date.

Studying for a Tech Interview Sucks, so Here's a Cheat Sheet to Help

This list is meant to be both a quick guide and reference for further research into these topics. It's basically a summary of that comp sci course you never took or forgot about, so there's no way it can cover everything in depth.

Contributing

General iOS, CS questions and interview prep resources.

Raywenderlich Swift Interview Questions and Answers
iOS Interview Questions for Senior Developers (useful even if you're not senior yet)
Swift Interview Tips by Sean Allen
My Approach to Learning iOS

WWDC18 Notes - Session 416 - iOS Memory Deep Dive

All session list link: Here
Session Link: Here
Demo starts @ 25:30 in the video.
Download session slides: Here

This notes is written by Sheldon after watching WWDC18 session 416. You can find me with #iOSBySheldon in Github, Youtube, Facebook, etc.

Performance Tips

Cancelling unnecessary downloading tasks

Once a downloading task initialized, even when you set another URL to the image view, that task will continue until finishes.

imageView.kf.setImage(with: url1) { result in 
 // `result` is `.failure(.imageSettingError(.notCurrentSourceTask))`

FastScrollingCollectionView

UICollectionView with optimized smooth scrolling and improved performance.

I expect that you use this when you want to add UICollectionView displaying images to your app.

Tips

1. Cache image

We can use SDWebImage. Standing on the shoulders of giants.

Async semantics proposal for Swift

Modern Cocoa development involves a lot of asynchronous programming using blocks and NSOperations. A lot of APIs are exposing blocks and they are more natural to write a lot of logic, so we'll only focus on block-based APIs.

Block-based APIs are hard to use when number of operations grows and dependencies between them become more complicated. In this paper I introduce asynchronous semantics and Promise type to Swift language (borrowing ideas from design of throw-try-catch and optionals). Functions can opt-in to become async, programmer can compose complex logic involving asynchronous operations while compiler produces necessary closures to implement that logic. This proposal does not propose new runtime model, nor "actors" or "coroutines".

	version: "3.9"
	services:
	mysql:
	container_name: mysql
	image: mysql:8.0
	command: --default-authentication-plugin=mysql_native_password
	restart: always
	environment:
	MYSQL_ROOT_PASSWORD: example
	MYSQL_DATABASE: car_rental

	//
	// CenteredCollectionViewFlowLayout.swift
	// CenteredCollectionView
	//
	// Created by Benjamin Emdon on 2016-09-05.
	// Copyright © 2016 Benjamin Emdon.
	//

	import UIKit

	// https://medium.com/@samermurad555/ios-provisional-notifications-eeb3832836fc

	import UserNotifications
	import UIKit

	typealias GrantCb = (_ didGrant: Bool) -> Void

	// Manages Notifications Permissions
	class NotificationManager {
	static let instance = NotificationManager()