Add sawtooth time chart

app/src/main/kotlin/info/appdev/chartexample/DataTools.kt

@@ -158,6 +158,10 @@ class DataTools {
             return result
         }
 
+        fun getSawtoothValues(size: Int): Array<Double> {
+            return Array(size) { i -> if (i % 2 == 0) -1.0 else 1.0 }
+        }
+
         fun setData(context: Context, lineChart: LineChart, count: Int = VAL_COUNT, range: Float = VAL_RANGE) {
             Timber.d("count=$count range=$range")
             val values = ArrayList<Entry>()

app/src/main/kotlin/info/appdev/chartexample/TimeLineActivity.kt

@@ -8,6 +8,8 @@ import android.view.MenuItem
 import androidx.core.net.toUri
 import androidx.lifecycle.lifecycleScope
 import info.appdev.chartexample.DataTools.Companion.generateSineWaves
+import info.appdev.chartexample.DataTools.Companion.getSawtoothValues
+import info.appdev.chartexample.custom.TimeMarkerView
 import info.appdev.chartexample.databinding.ActivityLinechartNoseekbarBinding
 import info.appdev.chartexample.formatter.UnixTimeAxisValueFormatter
 import info.appdev.chartexample.notimportant.DemoBase
@@ -25,6 +27,9 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext
+import timber.log.Timber
+import java.text.SimpleDateFormat
+import java.util.Locale
 
 class TimeLineActivity : DemoBase() {
     private var menuItemMove: MenuItem? = null
@@ -77,31 +82,66 @@ class TimeLineActivity : DemoBase() {
 
         binding.chart1.axisRight.isEnabled = false
 
-        setData(60f, TIME_OFFSET)
+        val timeMarkerView = TimeMarkerView(this, R.layout.custom_marker_view, "HH:mm:ss.sss")
+        timeMarkerView.chartView = binding.chart1
+        binding.chart1.marker.add(timeMarkerView)
+
+        setData(60f, TIME_OFFSET, true)
 
         binding.chart1.invalidate()
     }
 
     @Suppress("SameParameterValue")
-    private fun setData(range: Float, timeOffset: Long) {
+    private fun setData(range: Float, timeOffset: Long, sinus: Boolean) {
 
-        val sampleEntries = generateSineWaves(3, 30)
-            .mapIndexed { index, data ->
+        val sampleEntries = if (sinus)
+            generateSineWaves(3, 30).mapIndexed { index, data ->
                 val valueY = (data.toFloat() * range) + 50
                 Entry(timeOffset + index.toFloat() * 1000, valueY)
-            }.toMutableList()
+            }
+        else {
+            var previousEntry: Entry? = null
+            getSawtoothValues(14).mapIndexed { index, data ->
+                val valueY = data.toFloat() * 20
+                val entry = previousEntry?.let {
+                    // nay third value is 0, so we add here more then 1 second, otherwise we have a one second entry
+                    if (index % 3 == 0) {
+                        Entry(it.x + 3000, valueY)
+                    } else
+                        Entry(it.x + 1000, valueY)
+                } ?: run {
+                    Entry(timeOffset + index.toFloat() * 1000, valueY)
+                }
+                previousEntry = entry
+                // Now you can use 'prev' which holds the previous Entry
+                entry
+            }
+        }
+
+        val simpleDateFormat = SimpleDateFormat("HH:mm:ss.sss", Locale.getDefault())
+        sampleEntries.forEach { entry ->
+            val entryText = "Entry: x=${simpleDateFormat.format(entry.x)} x=${entry.x}, y=${entry.y}"
+            Timber.d(entryText)
+        }
 
         val set1: LineDataSet
 
         if (binding.chart1.lineData.dataSetCount > 0) {
             set1 = binding.chart1.lineData.getDataSetByIndex(0) as LineDataSet
-            set1.entries = sampleEntries
+            set1.entries = sampleEntries.toMutableList()
+            if (sinus)
+                set1.lineMode = LineDataSet.Mode.LINEAR
+            else
+                set1.lineMode = LineDataSet.Mode.STEPPED
             binding.chart1.lineData.notifyDataChanged()
             binding.chart1.notifyDataSetChanged()
         } else {
             // create a dataset and give it a type
-            set1 = LineDataSet(sampleEntries, "DataSet 1")
-
+            set1 = LineDataSet(sampleEntries.toMutableList(), "DataSet 1")
+            if (sinus)
+                set1.lineMode = LineDataSet.Mode.LINEAR
+            else
+                set1.lineMode = LineDataSet.Mode.STEPPED
             set1.axisDependency = YAxis.AxisDependency.LEFT
             set1.color = Color.rgb(255, 241, 46)
             set1.isDrawCircles = false
@@ -151,6 +191,17 @@ class TimeLineActivity : DemoBase() {
                 true
             }.isCheckable = true
         }
+        menuItemMove = menu?.add("Show sinus data")?.apply {
+            this.isChecked = true
+            setOnMenuItemClickListener { menuItem ->
+                menuItem.isChecked = !menuItem.isChecked
+                lifecycleScope.launch {
+                    setData(60f, TIME_OFFSET, menuItem.isChecked)
+                    binding.chart1.invalidate()
+                }
+                true
+            }.isCheckable = true
+        }
         return true
     }
 

app/src/main/kotlin/info/appdev/chartexample/custom/TimeMarkerView.kt

@@ -0,0 +1,40 @@
+package info.appdev.chartexample.custom
+
+import android.annotation.SuppressLint
+import android.content.Context
+import android.widget.TextView
+import info.appdev.chartexample.R
+import info.appdev.charting.components.MarkerView
+import info.appdev.charting.data.Entry
+import info.appdev.charting.highlight.Highlight
+import info.appdev.charting.interfaces.datasets.IDataSet
+import info.appdev.charting.utils.PointF
+import java.text.SimpleDateFormat
+import java.util.Locale
+
+@SuppressLint("ViewConstructor")
+class TimeMarkerView(context: Context?, layoutResource: Int, val format: String = "yyyy-MM-dd'T'HH:mm:ss'Z'") : MarkerView(context, layoutResource) {
+
+    private val simpleDateFormat = SimpleDateFormat(format, Locale.getDefault())
+    private val tvContent: TextView = findViewById(R.id.tvContent)
+
+    @SuppressLint("SetTextI18n")
+    override fun refreshContent(entry: Entry, highlight: Highlight) {
+        @Suppress("UNCHECKED_CAST")
+        val dataset = this.chartView?.data?.dataSets[0] as? IDataSet<Entry>
+        val myIndex = dataset?.getEntryIndex(entry)
+        val nextEntry = myIndex?.let {
+            if (it < dataset.entryCount - 1)
+                dataset.getEntryForIndex(myIndex + 1)
+            else
+                null
+        } ?: run { null }
+
+        val duration = if (nextEntry != null) " - duration:${(nextEntry.x - entry.x)}" else ""
+        tvContent.text = "${simpleDateFormat.format(entry.x)}$duration"
+        super.refreshContent(entry, highlight)
+    }
+
+    override var offset: PointF = PointF()
+        get() = PointF(-(width / 2).toFloat(), -height.toFloat())
+}