Passing data from an App VC to its widget

Question

Claude31 OP

Created Dec ’20

Replies 2

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Views 2.1k

Participants 2

Learning Widgets, I try a simple pattern:

get a textField in the app;
have the Widget updated when textField is changed.

App is UIKit.
Widget has No "included Configuration Intent".

It compiles and works. Widget is updated every 5 minutes as asked line 23 (final snippet).
But the message is never updated (line 48 of final snippet) with globalToPass (as expected from line 24): it always shows "Hello".

What I tried:

Create a singleton to hold the data to pass:

Code Block class Util {
    
    class var shared : Util {
        struct Singleton {
            static let instance = Util()
        }
        return Singleton.instance;
    }
    
    var globalToPass = "Hello"
}

shared the file between the 2 targets App and WidgetExtension

In VC, update the singleton when textField is changed and ask for widget to reload timeline

Code Block     @IBAction func updateMessage(_ sender: UITextField) {
        
        Util.shared.globalToPass = valueToPassLabel.text ?? "--"
        WidgetCenter.shared.reloadTimelines(ofKind: "WidgetForTest")
        WidgetCenter.shared.reloadAllTimelines()
    }

Problem : Widget never updated its message field

Probably I need to have the message in @State var, but I could not get it work.

Here is the full widget code at this time:

Code Block import WidgetKit
import SwiftUI
struct LoadStatusProvider: TimelineProvider {
    
    func placeholder(in context: Context) -> SimpleEntry {
        
        SimpleEntry(date: Date(), loadEntry: 0, message: Util.shared.globalToPass)
    }
    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        
        let entry = SimpleEntry(date: Date(), loadEntry: 0, message: Util.shared.globalToPass)
        completion(entry)
    }
    func getTimeline(in context: Context, completion: @escaping (Timeline<Entry>) -> ()) {
        var entries: [SimpleEntry] = []
        // Generate a timeline consisting of five entries an hour apart, starting from the current date.
        let currentDate = Date()
        for minuteOffset in 0 ..< 2 {
            let entryDate = Calendar.current.date(byAdding: .minute, value: 5*minuteOffset, to: currentDate)!
            let entry = SimpleEntry(date: entryDate, loadEntry: minuteOffset, message: Util.shared.globalToPass)
            entries.append(entry)
        }
        let timeline = Timeline(entries: entries, policy: .atEnd)
        completion(timeline)
    }
}
struct SimpleEntry: TimelineEntry {
    let date: Date
    let loadEntry: Int
    let message: String
}
struct WidgetForTestNoIntentEntryView : View {
    var entry: LoadStatusProvider.Entry
    var body: some View {
        let formatter = DateFormatter()
        formatter.timeStyle = .medium
        let dateString = formatter.string(from: entry.date)
        return
            VStack {
                Text(String(entry.message))
                HStack {
                    Text("Started")
                    Text(entry.date, style: .time)
                }
                HStack {
                    Text("Now")
                    Text(dateString)
                }
                HStack {
                    Text("Loaded")
                    Text(String(entry.loadEntry))
                }
            }
    }
}
@main
struct WidgetForTestNoIntent: Widget {
    let kind: String = "WidgetForTestNoIntent"
    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: LoadStatusProvider()) { entry in
            WidgetForTestNoIntentEntryView(entry: entry)
        }
        .configurationDisplayName("My Widget")
        .description("This is an example widget.")
    }
}
struct WidgetForTestNoIntent_Previews: PreviewProvider {
    static var previews: some View {
        
        WidgetForTestNoIntentEntryView(entry: SimpleEntry(date: Date(), loadEntry: 0, message: "-"))
            .previewContext(WidgetPreviewContext(family: .systemSmall))
    }
}

I have not defined extension for IntentHandler

Answered by Mcrich23 in 668396022

You pretty much have to. I use:

Code Block import UIKit
import WidgetKit
...
//code
//code for widget
UDM.shared.UserDefaults(suiteName: "group.whatever")?.setValue(urCode, forKey: "I'm a key")
WidgetCenter.shared.reloadAllTimelines()

Note: you have to set up a shared group between the app and the widget in the capabilities of the targets.

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Answer 1

Claude31 OP

Dec ’20

I read a solution by saving in userDefaults.
https://stackoverflow.com/questions/64240439/how-to-pass-uiviewcontroller-data-to-swiftui-widget-class

But I would prefer not having to save, just using singleton if possible.

0

Answer 2

Mcrich23 OP

Mar ’21

Accepted Answer

You pretty much have to. I use:

Code Block import UIKit
import WidgetKit
...
//code
//code for widget
UDM.shared.UserDefaults(suiteName: "group.whatever")?.setValue(urCode, forKey: "I'm a key")
WidgetCenter.shared.reloadAllTimelines()

Note: you have to set up a shared group between the app and the widget in the capabilities of the targets.

0