Parse-Swift example for SwiftUI App life cycle

cappern · January 29, 2021, 8:26am

Hi, beeing a total noob in swift programming I find it hard to implement Parse-swift with the “new” SwiftUI app life cycle.
Does anyone care to share any examples to get my project started?

-Cappern

alexvenom · January 29, 2021, 7:15pm

Hey @cappern!
I just created an Github project with Parse in SwiftUI. Very simple stuff: only configures Parse and in the ContentView it makes a simple query printing stuff on the onAppear event.
Hope it helps you.
Here is the link for it:

cbaker6 · January 30, 2021, 7:27am

If you are referring to the recently released Parse-Swift SDK. This project uses it

To see how you would implement a login screen in SwiftUI you can look at these files:

github.com

netreconlab/CareKitSample-ParseCareKit/blob/main/OCKSample/Login/LoginView.swift

//
//  LoginView.swift
//  OCKSample
//
//  Created by Corey Baker on 10/29/20.
//  Copyright © 2020 Apple. All rights reserved.
//

// This is a variation of the tutorial found here: https://www.iosapptemplates.com/blog/swiftui/login-screen-swiftui

import SwiftUI
import ParseSwift
import UIKit

struct LoginView: View {
    
    //Anything is @ is a wrapper that subscribes and refreshes the view when a change occurs. List to the last lecture in Section 2 for an explanation
    @ObservedObject private var login = Login()
    @State private var usersname = ""
    @State private var password = ""

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github.com

netreconlab/CareKitSample-ParseCareKit/blob/main/OCKSample/Login/Login.swift

//
//  LoginViewModel.swift
//  OCKSample
//
//  Created by Corey Baker on 11/24/20.
//  Copyright © 2020 Apple. All rights reserved.
//

import Foundation
import ParseSwift
import CareKit
import CareKitStore

class Login: ObservableObject {

    private(set) var isLoggedIn = false {
        willSet {
            objectWillChange.send() //Publishes a notification to subscribers whenever this value changes
        }
    }

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Parse-Swift will receive some additional updates soon to make it easier to use with Parse-Swift. For now, you can look at the last file I posted to see how to add Parse-Swift to a view model

cbaker6 · January 31, 2021, 12:06am

There’s currently a pending PR on Parse-Swift that makes the SDK directly functional with SwiftUI, reducing the need to make custom view models for api calls to a Parse Server. The ParseLiveQuery part of Parse-Swift has it’s own view model (Subscription) that can already keep your SwiftUI views up-to-date. The PR is below:

github.com/parse-community/Parse-Swift

Add combine publishers for all objects and types

parse-community:main ← parse-community:combine

opened 10:31PM - 30 Jan 21 UTC

cbaker6

+4996 -1163

Adding the publishers such as `Future` to all one-shot async calls, making Parse…-Swift modernized and SwiftUI ready. All methods that are capable of “publishing” end with the word `Publisher`. This means that there are 3 ways to use most of the methods that send/receive info to a Parse Server: 1) sync, 2) async, and 3) publisher. As far as usage, you use the added publishers just like any other `Combine` publisher. The thing to remember is that all of the push/pull methods like `save`, `fetch`, etc. are `Futures`, so they start their work as soon as you call them and will only publish one result when finished. Any new subscriptions to an already fulfilled`Future` will produce the original result. This is different from the `ParseLiveQuery` `Subscription` which will keep publishing events/subscriptions as long as it’s not cancelled. `Combine` currently isn't supported on Linux, but if/when it ever is the combine features will automatically be available for use. Linux devs can use the async/sync callbacks instead. - [x] All objects publishable - [x] All types publishable - [x] Testcases - [x] Some fixes to `ParseUser.logout` to make it more predictable - [x] Bring minimum deployment to the same level on Xcode, SPM, and Cocoapods, `[.iOS(.v12), .macOS(.v10_13), .tvOS(.v12), .watchOS(.v5)]`. If a developer wants to support an older platform, they should use the [Parse-Obj-C SDK](https://github.com/parse-community/Parse-SDK-iOS-OSX) Slightly breaking (compiler should suggest the correct fix): - `delete`, `deleteAll`, `passwordReset`, and `verificationEmail` use to all return an `ParseError`. These have all been switched to return a Result<Void, ParseError> instead to match everything else. This is helpful, because `Future` expects a result enum anyways

cappern · January 31, 2021, 6:49pm

Thanks, I kinda found out on my own, but there sure was room for improvement
@cbaker6, keep up the good work!

cbaker6 · January 31, 2021, 8:18pm

Version 1.1.3 has publisher support:

Check the documentation for information about the Publishers (look for “Combine” or “Publisher”).

The previous versions still support SwiftUI, you would just use sync/async calls in your view model instead of using “…Publisher” like in my previous links.