Guide to SwiftUI layout and presentation controls in iOS

SwiftUI Layout Containers

It is always better to know about all the tools before you start your DIY project. You need to know what tools are available and what each tool can be used for. The same strategy can be applied to UI design. If you know all the available tools provided by the SwiftUI framework then you will be able to apply that knowledge to the beautiful designs that your designer has provided you with. Following are the Layout containers provided by SwiftUI.

HStack

you can refer HStack as a horizontal stack. You want to stack your controls shown in the image below. 

The views in SwiftUI are aligned in a similar fashion as shown in image below. 

LazyHStack

As the name says this is a Lazy container. As the keyword, Lazy in a programming language is a strategy to delay the initialization until it is needed. The views in the LazyStack are not initialized until they are needed. 

You can try this code and see how it works. 

import SwiftUI

struct CustomText: View {

  private let index: Int

  init(index: Int) {

    print("init CustomText \(index)")

    self.index = index

  }

  var body: some View {

    Text("This is custom text view")

  }

}

struct ContentView: View {

    var body: some View {

      ScrollView(.horizontal) {

        LazyHStack {

          ForEach(0...100, id:\.self) { index in

            CustomText(index: index)

          }

        }

      }

    }

}

It should look like as shown in image below when you first run it. 

VStack

The Stack is referred to as vertical stack e.g. as shown in the image below

The corresponding SwiftUI views are stacked in a similar fashion as shown in the image below.

LazyVStack

LazyVStack works very similar to LazyHStack, it's just that it will align the items vertically. Before you read further, I want you to try the code from the LazyHStack section and just change the LazyHStack to LazyVStack. 

Check the output in the debug window. Must be wondering what is going on there. All the items are getting rendered. 

So what should you do it fix it? Try it before looking at the code below. 

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|

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I am sure you have tried it. The thing is that you need to change the ScrollView to be .vertical.

import SwiftUI

struct CustomText: View {

  private let index: Int

  init(index: Int) {

    print("init CustomText \(index)")

    self.index = index

  }

  var body: some View {

    Text("This is custom text view")

  }

}

struct ContentView: View {

    var body: some View {

      ScrollView(.vertical) {

        LazyVStack(alignment: .center, spacing: 50) {

          ForEach(0...100, id:\.self) { index in

            CustomText(index: index)

          }

        }

      }

    }

}

Ionic Capacitor CI/CD using new yaml pipeline with multiple stages

The Ionic Capacitor is a new framework to build cross-platform apps. In this article, we will learn how to set up an Azure DevOps pipeline to build and deploy to AppCenter to distribute to test users.

For simplicity, I am going to build only the android project in this article. You can always add more jobs to run in parallel to build the other environments. Also, I am assuming that you have some experience build Azure pipelines and know about defining variables in the pipeline and how to store secrets in Secure Files and Variables. Please let me know in the comments if there anything specific about the pipeline you don't understand,

I started with creating an empty yaml pipeline and here you have different options to choose your repo from. I have my repo on Azure reports Git and will select that and choose my repo from the next screen. 

 

Once you select your repo you will get some recommendations in the Configure 

I picked up the starter pipeline to get the basic pipeline in place, which will checkout the branch based on the trigger branch, which by default will be master.

Once you select the Starter pipeline you will get something like this.

# Starter pipeline

# Start with a minimal pipeline that you can customize to build and deploy your code.

# Add steps that build, run tests, deploy, and more:

# https://aka.ms/yaml

trigger:

- master

pool:

  vmImage: 'ubuntu-latest'

steps:

- script: echo Hello, world!

  displayName: 'Run a one-line script'

- script: |

    echo Add other tasks to build, test, and deploy your project.

    echo See https://aka.ms/yaml

  displayName: 'Run a multi-line script'

we will start to make changes to the pipeline.

Weather App SwiftUI, OpenWeatherMap and Combine using MVVM

I have started the iOS 13 & Swift 5 course on Udemy. I am really loving the course, the instructor Angela is awesome. 

I was not interested in UIKit development and I had started and stopped few times in past years with UIKit. But, SwiftUI is something that is bringing my interest back to iOS development. 

But wait, you must be wondering that course is in UIKit and I really do not like UIKit. What I decided to do is to build the projects in SwiftUI and Combine. This path is really slow and I would suggest to folllow this path you are interested in learning both at a time. I had few knowledge of UIKit before I started this course so I am just figuring new stuff in UIKit. 

you can find the code for the app here https://github.com/karm435/Udemy-iOS14-Samples/tree/master/Clima-iOS14

The course has a Weather app that looks like this. 

LightMode

DarkMode

I have name the files  with suffux 'Model', 'ViewModel', 'Service' and 'View' so that you can identify the parts of the MVVM pattern easily. 

Most time cosuming part of the learning was understanding the Combine and how to structure the app using Combine framework. If you want to take a Deep Dive into Combine framework, I really encourage you to read through https://heckj.github.io/swiftui-notes/#introduction

Learnings while converting this project to SwiftUI

Supporting Light and Dark Mode

Starting with the background of the app. You will have to upload assets for each type of appearance in the assets folder. 

Similar to background you can set the AccentColor of the app to be different for different environment and add additional color sets for primary or secondary colors. 

Using Combine

If you are new to Functional Reactive Programming, I would suggest give a read https://blog.danlew.net/2017/07/27/an-introduction-to-functional-reactive-programming/. 

Using Delegate Pattern in SwiftUI

I needed to get the current location of the User. So to do that I need to conform to CLLocationManagerDelegate protocol. You can check the implementation in the code in WeatherViewModel.

WWDC 2020 Keynote Highlights

AirPods

• AirPods now magically switch between your devices as you use devices that would logically call for AirPods to be connected

• AirPods Pro now supports spacial audio to emulate a theatre like immersive surround sound experience… this takes into a account head movement to map the sound field and anchor it to your device, so if you move your device and head the surround sound pivots to keep you at the centre! 

AppleWatch and WatchOS7

• You can now have multiple rich complications on the one watch face

• You can now download tailored watch faces, or create your own pre configured watch faces and share them via iMessage 

• Maps on watch will include the new cycling directions from Maps 

• Workouts now includes ‘Dance’ and it can tell if you’re dancing with your whole body, just lower or just upper body

• Core training, Functional strength training and cool downs also added 

• The activity app is completely redesigned on iPhone and has been renamed to ‘Fitness’ 

• Sleep tracking is finally here! It allows you to set goals on bedtime and wake times. 

• In the evening, your phone can start a ‘wind-down’ process which will turn on do not disturb and can start your meditation app or some relaxing music 

• The wake up alarm can be Taptic so you don’t wake your partner

• When you’re sleeping you have to tap the screen for it to light up to show time

• There is now a hand washing feature in WatchOS that makes sure you’re washing your hands effectively and for long enough

Privacy

• ‘Sign in with Apple’ now allows developers to help users move their existing accounts across to sign in with apple access 

• With location sharing, you can choose to share your precise, or just approximate location 

• Apps have to have a privacy policy, but it’s usually hidden, so they now have a ‘nutrition label’ style label on the App Store page so you can see a summary of the apps privacy practices. 

Home

• Apple, Amazon and Google have formed an alliance on smart home standards

• Homekit is now open sourced

• The flow for adding Homekit devices 

• Activity zones and face recognition now supported for all cameras in Home, and it will recognise faces of friends and family you’ve tagged in your photos app

• You can now view cameras and your doorbell camera on Apple TV! 

AppleTV

• AppleTV supports the new Xbox adaptive controller and the new Elite controller

• You can use PIP anywhere within AppleTV (so watch the news while you use a workout app etc)

• Airplay now supports 4K 

MacOS

• The new version of MacOS is called MacOS Big Sur

• The OS has been refined, it has more of an iOS feel

• New icons, controls, surfaces

• Consistent highlight tints in apps, rounded row selection styles

• Control centre can be customised and you can add quick actions to your top bar

• Notifications look and are grouped like in iOS

• The new iOS widgets have been bought to the Mac too 

• MacOS Messages: Now has refined search; supports message effects, Memoji stickers and the other enhancements that were added to group chats 

• Catalyst has updates including Total Pixel control, Mac specific interactions and date pickers

• Safari on MacOS: redesigned, more effective tab management, page translation built in

Mac is moving to their own Apple silicon (ARM chips) 

• All the new native Apple apps work on the new chips…. Including Xcode, Final cut etc

• Using a new tool called Universal2 developers can use a single binary to make apps work on both the Apple Silicon and old Intel Macs 

• Microsoft and Adobe are already onboard and have built many of their apps to work on the new Apple Silicon

• Microsoft Office is already built out to support the new Apple chips … and Powerpoint is using Metal for rendering. 

• Adobe Lightroom and Photoshop have also been converted

• Rosetta2 converts existing Mac apps automatically… even games can be converted for the user automatically…. (They demo’d the latest Tomb Raider) 

• iPhone and iPad apps will run on the new Arm MACs completely unmodified! 

Todo app using SwiftUI

It's time again and I started learning the iOS programming again as SwiftUI looks cool.

I spent couple of weeks going through the swift programming documentation and watched the WWDC videos. 

Note: This is an ongoing blog, which I update as I add more features to my TodoApp.

Learning

Follow along the Swift documentation. Try to code along the examples. Just go through the documentation even if you don't understand the whole thing just try to read all the documentation and get yourself aware with the concepts. This is will help later while reading the code of some

open source project. 

And.. read the documentation again. This is what I am doing now, this time try to understand and repeat until it becomes muscle memory. this is ongoing process.

SwiftUI

Follow the SwiftUI tutorials and try to recreate them. 

Videos

One of my colleague suggested WWDC videos and watch them in the order. 

• SwiftUI Essentials
• Data Flow Through SwiftUI
• Introducing SwiftUI: Building your first app
• Mastering Xcode Previews
• Protocol-Oriented Programming in Swift
• Building Better Apps with Value Types in Swift

Blogs

• Ole Begemann
• Paul Hudson

After going through all those videos and tutorials, I have decided to start creating something. So what is first app everyone build, it's Todo app. 

iOS-TodosApp

Download the Github repo to follow along and try the completed features.

Features

• Create a new Todo
• Context menu to Complete or Delete a Todo
• Show completed tasks
• Add Priority
• Add Date

Upcoming

• Edit 
• Persist the data
• Add Notification
• Add Location
• Login functionality

Learnings while doing TodoApp