aclima93

Swift UI State Management

Storing state for Child View Models

SwiftUI is all about state, and maintaining that state can be rather difficult when you have more than a few properties stored as @State for your view. It is common practice to use a view model to store the state outside of the view, since our views are constantly recreated as our state changes. Keeping what state you want in memory can provide a challenge, much more so than it may seem at first glance.

With SwiftUI 2, using @StateObject will keep a view model from being recreated with each rendering of a view's body. If the parent view is creating the view model, and then passing that down to the child view, that view model will also be recreated with each rendering of that parent view body.

struct ParentView: View {
  var body: some View {

aclima93

#! /bin/bash

# datetime
datetime=$(date +%d/%m/%Y)

# git branch name
branch_name=$(git rev-parse --abbrev-ref HEAD)

# for branches that follow the `<dir>/<ticket|NOJIRA>-<title>` naming convention and
# regex `(?<branch_dir>(\w+\/)+)?(?<ticket>(\w+-\d+)|(NOJIRA))[-//](?<title>(\w+-?)+)`

aclima93

class LeakCheckTestCase: XCTestCase {

    private var excludedProperties = [String: Any]()
    private var weakReferences = NSMapTable<NSString, AnyObject>.weakToWeakObjects()

    // MARK: - SetUp

    override func setUpWithError() throws {

        try super.setUpWithError()

aclima93

#!/usr/bin/env xcrun --sdk macosx swift
// A build phase script for fetching, validating and generating a Swift wrapper over configuration files in iOS projects
// Source: https://github.com/pgorzelany/SwiftConfiguration

import Foundation

public struct ParsedArguments {
    public let configurationPlistFilePath: String
    public let outputFilePath: String
}

aclima93

#!/usr/bin/env bash

# default values
SRC=${1:-_site/}
DST=${2:-docs/}
USER_PAGE=${3:-../aclima93.github.io/}
BLOG_PAGE=${3:-../Blog/docs/}

# copy the contents from $SRC (_site/) to $DST (doc/) and serve that over at github-pages
rm -rf $DST;

aclima93

Keybase proof

I hereby claim:

• I am aclima93 on github.
• I am aclima93 (https://keybase.io/aclima93) on keybase.
• I have a public key ASDVtyOtAN-HfNRgZVWoyoP053JtAG1EMvqctW440zMDzAo

To claim this, I am signing this object:

aclima93

func addPOIToARScene(_ poi: PointOfInterest) {
    // create node
    let location = CLLocation(latitude: poi.latitude, longitude: poi.longitude)
    let text = poi.title
    let annotationNode = LocationTextAnnotationNode(location: location, image: UIImage(named: "LocationMarker")!, text: text)

    // add node to AR scene
    sceneLocationView.addLocationNodeWithConfirmedLocation(locationNode: annotationNode)
}

aclima93

open class LocationTextAnnotationNode: LocationNode {
    
    // image and text that are displayed by the child nodes
    public let image: UIImage
    public let text: String
    
    // child nodes
    public let imageAnnotationNode: SCNNode
    public let textAnnotationNode: SCNNode
    

aclima93

var locationManager: CLLocationManager!
var latestLocation: CLLocation?
var pois: [PointOfInterest]!

func getPOIs() {

    // formulate natural language query for nearby POIs
    let request = MKLocalSearch.Request()
    request.naturalLanguageQuery = "Restaurants" // or any other thing you might be interested in
    request.region = MKCoordinateRegion(center: (latestLocation?.coordinate)!,

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var sceneLocationView: SceneLocationView!
var pois: [PointOfInterest]!
var locationAnnotationNode2POI: [LocationTextAnnotationNode: PointOfInterest]!
var selectedPOI: PointOfInterest?

func setupARScene() {
    // create AR scene
    sceneLocationView = SceneLocationView()
    view.addSubview(sceneLocationView)