Merge pull request #599 from AppDevNext/GradientIssue

Show gradienten issue as a sample

Author: hannesa2

app/src/main/AndroidManifest.xml

@@ -53,6 +53,7 @@
         <activity android:name="info.appdev.chartexample.StackedBarActivityNegative" />
         <activity android:name="info.appdev.chartexample.BarChartPositiveNegative" />
         <activity android:name="info.appdev.chartexample.FilledLineActivity" />
+        <activity android:name="info.appdev.chartexample.GradientActivity" />
         <activity android:name="info.appdev.chartexample.HalfPieChartActivity" />
         <activity android:name="info.appdev.chartexample.SpecificPositionsLineChartActivity" />
     </application>

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

@@ -0,0 +1,78 @@
+package info.appdev.chartexample
+
+import android.os.Bundle
+import androidx.activity.enableEdgeToEdge
+import androidx.core.content.ContextCompat
+import androidx.core.view.ViewCompat
+import androidx.core.view.WindowInsetsCompat
+import info.appdev.chartexample.notimportant.DemoBase
+import info.appdev.charting.charts.LineChart
+import info.appdev.charting.data.Entry
+import info.appdev.charting.data.LineData
+import info.appdev.charting.data.LineDataSet
+import info.appdev.charting.formatter.IFillFormatter
+import info.appdev.charting.interfaces.dataprovider.LineDataProvider
+import info.appdev.charting.interfaces.datasets.ILineDataSet
+import info.appdev.charting.utils.Utils
+
+class GradientActivity : DemoBase() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        enableEdgeToEdge()
+        setContentView(R.layout.activity_gradient)
+
+        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
+            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
+            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
+            insets
+        }
+
+        Utils.init(this)
+
+        val chart: LineChart = findViewById(R.id.chart)
+
+        // Minimal chart setup
+        chart.description?.isEnabled = false
+        chart.legend?.isEnabled = false
+        chart.axisRight.isEnabled = false
+        chart.setDrawGridBackground(false)
+
+        // -----------------------------
+        // Linear function
+        // y = k * x
+        // -----------------------------
+        val entries = kotlin.collections.ArrayList<Entry>(200)
+        val k = 2.5f
+
+        for (i in 0 until 200) {
+            entries.add(Entry(i.toFloat(), i * k))
+        }
+
+        val dataSet = LineDataSet(entries, "Linear").apply {
+            isDrawValues = false
+            isDrawCirclesEnabled = false
+            lineWidth = 2f
+
+            isDrawFilledEnabled = true
+            fillAlpha = 255
+            fillDrawable = ContextCompat.getDrawable(
+                this@GradientActivity,
+                R.drawable.gradient_drawable_precipitation
+            )
+
+            fillFormatter = object : IFillFormatter {
+                override fun getFillLinePosition(
+                    dataSet: ILineDataSet?,
+                    dataProvider: LineDataProvider
+                ): Float = chart.axisLeft.axisMinimum
+            }
+        }
+
+        chart.axisLeft.axisMinimum = 0f
+        chart.setData(LineData(dataSet))
+        chart.invalidate()
+    }
+
+    override fun saveToGallery() = Unit
+}

app/src/main/kotlin/info/appdev/chartexample/notimportant/MainActivity.kt

@@ -54,6 +54,7 @@ import info.appdev.chartexample.CombinedChartActivity
 import info.appdev.chartexample.CubicLineChartActivity
 import info.appdev.chartexample.DynamicalAddingActivity
 import info.appdev.chartexample.FilledLineActivity
+import info.appdev.chartexample.GradientActivity
 import info.appdev.chartexample.HalfPieChartActivity
 import info.appdev.chartexample.HorizontalBarChartActivity
 import info.appdev.chartexample.InvertedLineChartActivity
@@ -208,6 +209,9 @@ class MainActivity : ComponentActivity() {
 
             add(ContentItem("Compose Horizontal"))
             add(ComposeItem("Horizontal", "Render bar chart horizontally.", HorizontalBarComposeActivity::class.java).toDemoBase())
+
+            add(ContentItem("Demonstrate and fix issues"))
+            add(ContentItem("Gradient", "Show a gradient edge case", GradientActivity::class.java))
         }
     }
 }

app/src/main/res/drawable/gradient_drawable_precipitation.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<shape xmlns:android="http://schemas.android.com/apk/res/android">
+	<gradient
+		android:type="linear"
+		android:angle="-90"
+		android:endColor="#005183F0"
+		android:startColor="#5923BAFF" />
+</shape>

app/src/main/res/layout/activity_gradient.xml

@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:id="@+id/main"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".GradientActivity">
+
+
+    <info.appdev.charting.charts.LineChart
+        android:id="@+id/chart"
+        android:layout_width="0dp"
+        android:layout_height="0dp"
+        android:layout_margin="16dp"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+
+</androidx.constraintlayout.widget.ConstraintLayout>