Custom text in persistentMarker label

[janouseko]

Question

How can I add custom text to a persistentMarker label in Vico?

For example, if a user presses button "A", this triggers runTransaction, and a persistentMarker appears in the chart with its value ("50"). However instead of its value, I want custom label, such as "A", "B", "start" or "happend here".

I truly appreciate the effort put into developing the Vico library and its comprehensive documentation. However, I couldn’t find a concrete example or guide on how to implement this specific functionality. Could you provide an example or point me in the right direction? Many thanks!

Vico version(s)

2.0.0-beta.2

UI framework(s)

Jetpack Compose

[Gowsky]

Hello, @janouseko. I assume you're using DefaultCartesianMarker. In Vico 2.0.0 Beta 2, you can achieve the desired result via CartesianMarkerValueFormatter. An instance of this interface can be applied to a DefaultCartesianMarker via the valueFormatter constructor parameter.

I couldn’t find a concrete example or guide on how to implement this specific functionality

It was covered in the guide for 2.0.0 Beta 2, but since this version is outdated, the guide is no longer available. Here is the equivalent section of the 2.0.0 guide. Generally, this guidance applies to 2.0.0 Beta 2 too, but some names have changed.

[janouseko]

Hi @Gowsky, thank you for your help! I have tried to apply CartesianMarkerValueFormatter to a DefaultCartesianMarker via valueFormatter according to the guidelines for Vico 2.0.0, however I failed. Could you please provide some example, so I can understand, what I am missing? Thank you a lot! Really appreciate your time.

---

I have ended with this code, which at least compiles in Android Studio, however my app crashes on tablet.

val marker = DefaultCartesianMarker(
    valueFormatter = object : CartesianMarkerValueFormatter {
        override fun format(
            context: CartesianDrawingContext,
            targets: List<CartesianMarker.Target>
        ): CharSequence {
            return "custom text" // Your custom label, e.g., "Ahoj"
        }
    },
)

[Gowsky]

Please be more specific.

however I failed

What kind of issue are you facing? Does the label remain unchanged, or does this refer to the crash mentioned later?

however my app crashes on tablet

Please share the stack trace.