Nested TimelineView and List cause hang issue

Question

Ukjeong Lee OP

Created 2w

Replies 1

Boosts 0

Participants 2

Hello. I’ve encountered a strange issue with TimelineView and wanted to report it.

The following code runs without any problems:

// Example 1.
struct ContentView: View {
    var body: some View {
        TimelineView(.everyMinute) { _ in
            List {
                TimelineView(.everyMinute) { _ in
                    Text("Hello")
                }
            }
        }
    }
}

However, the code below causes the CPU usage to spike to 100%, and the screen displays a blank view:

// Example 2.
struct ContentView: View {
    var body: some View {
        TimelineView(.everyMinute) { _ in
            List {
                TimelineView(.everyMinute) { _ in
                    text
                }
            }
        }
    }
    
    var text: some View {
        Text("Hello")
    }
}

The same issue occurs with the following code:

// Example 3.
struct MyTextView: View {
    var body: some View {
        Text("Hello")
    }
}

struct ContentView: View {
    var body: some View {
        TimelineView(.everyMinute) { _ in
            List {
                TimelineView(.everyMinute) { _ in
                    MyTextView()
                }
            }
        }
    }
}

Replacing List with LazyVStack and ForEach resolves the hang issue, but I need to use List because I rely on the swipeActions().

Does anyone have insights or suggestions on how to address this issue?

Boost

Answer 1

darkpaw OP

1w

What happens if you remove the unnecessary second TimelineView?

struct ContentView: View {
    var body: some View {
        TimelineView(.everyMinute) { _ in
            List {
                text
            }
        }
    }
    
    var text: some View {
        Text("Hello")
    }
}

You're already updating the contents of the first TimelineView every minute on the minute, so why do you need a second one inside?

Maybe, if that doesn't work, how about putting the second one back and removing the first?

struct ContentView: View {
    var body: some View {
        List {
            TimelineView(.everyMinute) { _ in
                text
            }
        }
    }
    
    var text: some View {
        Text("Hello")
    }
}

0