How does Marker works when using XML and not compose

[DannyBloky]

I had a question about the markers.

I don't understand the documentation about it how I can use the markers.

I'm using version 1.13.1

I'm using this chart:
<com.patrykandpatrick.vico.views.chart.ChartView android:id="@+id/lineChart" android:layout_width="match_parent" android:layout_height="200dp" app:chart="line" app:showBottomAxis="true" app:showStartAxis="true" />

This is inside my Fragment now
`override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
observeBaseViewModel(viewModel)

    val binding = FragmentBinding.bind(view)
    val endColor = getColorWithPercentAlpha(requireContext(), R.color.backgroundColorBlue, 0.05)
    val startColor =
        getColorWithPercentAlpha(requireContext(), R.color.backgroundColorBlue, 0.7)

    viewModel.chartData.observe(viewLifecycleOwner) { value ->
        val entryModelProducer = ChartEntryModelProducer()

        val list = mutableListOf<FloatEntry>()
        for (item in value) {
            list.add(
                FloatEntry(
                    item.receivedAtDate.toEpochSecond(ZoneOffset.UTC).toFloat(),
                    item.value.toFloat()
                )
            )
        }
        entryModelProducer.setEntries(list)
        binding.lineChart.entryProducer = entryModelProducer
    }

    with(binding) {
        //Chart
        with(binding.lineChart.bottomAxis as HorizontalAxis) {
            valueFormatter = bottomAxisValueFormatter
            itemPlacer = startAxisXItemPlacer
            label = textComponent {
                color = R.color.gray_date
                textSizeSp = 12f
            }
            axisLine?.color = Color.BLACK
            guideline?.color = Color.TRANSPARENT
        }

        with(binding.lineChart.chart as LineChart) {
            addDecorations(
                listOf(
                    ThresholdLine(
                        20000f,
                        "",
                        lineComponent = ShapeComponent(
                            color = Color.RED
                        )
                    ),
                    ThresholdLine(
                        25000f,
                        "",
                        lineComponent = ShapeComponent(
                            color = Color.RED
                        )
                    )
                )
            )

            lines[0].lineColor = R.color.backgroundColorBlue
            lines[0].lineBackgroundShader =
                DynamicShaders.verticalGradient(startColor, endColor)
        }

        with(binding.lineChart.startAxis as VerticalAxis) {
            itemPlacer = startAxisYItemPlacer
            label = textComponent {
                color = R.color.gray_date
                textSizeSp = 12f
            }
            axisLine?.color = Color.BLACK
            guideline?.color = Color.TRANSPARENT
        }
    }
}`

This code will show a line chart with 2 tresholds and a line graph with gradient area.
Also custom labels on my x line with dates.

But I want also have the click function on the chart that show the marker. But I don't understand or is this not possible in xml. I don't see a property like enable marker or something.

Only thing is Marker and add addPersistentMarker
But as far I can see is that just 1 marker on a specific place. Also don't get that to work either. So if someone can help me with this

[patrickmichalik]

Hello! This is described in the wiki. Please see the second paragraph here.

[DannyBloky]

Thanks for your reply. I have read the documentation but I didn't understand it. So if you can help me that would be great how to do it.

[csbenz]

@DannyBloky Is LineChart part of this library? I can't find it, I'm trying to set the color of my lines.

[patrickmichalik]

You can add a standard Marker by updating lineChart.marker, @DannyBloky. For example, if you’re creating your Marker via MarkerComponent, use the following:

lineChart.marker = MarkerComponent(/* ... */)

By the way, it looks like you’re recreating your ChartEntryModelProducer on every data update. This is discouraged and may cause unexpected behavior. I’d recommend using a single ChartEntryModelProducer and storing it at a higher level.

@csbenz, LineChart is a Vico 1 class. In Vico 2, use LineCartesianLayer.

[DannyBloky]

Thank you I now got the text of the Marker. If I got any question later about it I will ask them.

Good point. I saw it when I was changing the data. Then the chart will be blank. So I did your suggestion for the ChartEntryModelProducer and now it can update the data.

[patrickmichalik]

I’m glad to hear that, @DannyBloky. You’re welcome!

[DannyBloky]

@DannyBloky Is LineChart part of this library? I can't find it, I'm trying to set the color of my lines.

lines[0].lineColor = R.color or Color.
It in the with(binding.lineChart.chart as LineChart)

By this you can set the color of the line