How to Create Custom Shapes of Data Points in GraphView in Android?

23 May, 2021
If you are looking for a view to represent some statistical data or looking for a UI for displaying a graph in your app then in this article we will take a look at creating a line graph view and showing custom shape to the data points in our Android App.  
We will be building a simple Line Graph View in our Android app and we will be displaying some sample data with custom shapes in our application. Note that we are going to implement this project using the Java language. 
Step 1: Create a New Project
To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Java as the programming language.
Step 2: Add dependency
Navigate to the Gradle Scripts > build.gradle(Module:app) and add the below dependency in the dependencies section.   
implementation ‘com.jjoe64:graphview:4.2.2’
Step 3: Working with the activity_main.xml file
Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file. 
XML
<?xml version="1.0" encoding="utf-8"?><RelativeLayout     xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity">      <com.jjoe64.graphview.GraphView        android:id="@+id/graphview"        android:layout_width="match_parent"        android:layout_height="match_parent" />      </RelativeLayout>
Step 4: Working with the MainActivity.java file
Go to the MainActivity.java file and refer to the following code. Below is the code for the MainActivity.java file. Comments are added inside the code to understand the code in more detail.
Java
import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;  import androidx.appcompat.app.AppCompatActivity;  import com.jjoe64.graphview.GraphView;import com.jjoe64.graphview.series.DataPoint;import com.jjoe64.graphview.series.DataPointInterface;import com.jjoe64.graphview.series.PointsGraphSeries;  public class MainActivity extends AppCompatActivity {          GraphView graphView;      @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        graphView = findViewById(R.id.graphview);          // For creating Point Graph Series We use PointGraphSeries        PointsGraphSeries<DataPoint> series = new PointsGraphSeries<>(getDataPoint());          graphView.addSeries(series);                  // we use this method to define the shape that        // will be used for data points        // series.setShape(PointsGraphSeries.Shape.TRIANGLE);        // we use this method to define the size of the shape        series.setSize(50);                  // we use this method to set the color        series.setColor(Color.RED);                  // we use this method to define the custom shape,        // we create our own shape        series.setCustomShape(new PointsGraphSeries.CustomShape() {            @Override            public void draw(Canvas canvas, Paint paint, float x, float y, DataPointInterface dataPoint) {                paint.setStrokeWidth(5);                // we are initialising the shape structure of dat points                canvas.drawLine(x - 20, y, x, y - 20, paint);                canvas.drawLine(x, y - 20, x + 20, y, paint);                canvas.drawLine(x + 20, y, x, y + 20, paint);                canvas.drawLine(x - 20, y, x, y + 20, paint);            }        });    }      // initialising the data points    private DataPoint[] getDataPoint() {        DataPoint[] dp = new DataPoint[]{                new DataPoint(0, 1),                new DataPoint(2, 1),                new DataPoint(3, 5),                new DataPoint(6, 2),                new DataPoint(7, 8),        };        return dp;    }}
Output:
Android
Java
Java
Android
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