Example of Paint.setShader() with SweepGradient

More examples of drawing on canvas of custom View listed HERE.

Example of Paint.setShader() with SweepGradient:

Create a custom View to draw with Paint to apply SweepGradient, MyView.java.

package com.example.androiddraw;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.SweepGradient;
import android.util.AttributeSet;
import android.view.View;

public class MyView extends View {
 
 Paint BackPaint = new Paint();
 Context MyContext;

 public MyView(Context context) {
  super(context);
  init(context);
 }

 public MyView(Context context, AttributeSet attrs) {
  super(context, attrs);
  init(context);
 }

 public MyView(Context context, AttributeSet attrs, int defStyle) {
  super(context, attrs, defStyle);
  init(context);
 }
 
 private void init(Context ctx){
  MyContext = ctx;
  BackPaint.setStyle(Paint.Style.FILL);
  BackPaint.setColor(Color.BLACK);
  
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  int w = MeasureSpec.getSize(widthMeasureSpec);
  int h = MeasureSpec.getSize(heightMeasureSpec);
  setMeasuredDimension(w, h);
 }

 @Override
 protected void onDraw(Canvas canvas) {

  float w, h, cx, cy, radius;
  w = getWidth();
  h = getHeight();
  cx = w/2;
  cy = h/2;
  
  if(w > h){
   radius = h/4;
  }else{
   radius = w/4;
  }
  
  canvas.drawRect(0, 0, w, h, BackPaint);
  
  Paint MyPaint = new Paint();
  MyPaint.setStyle(Paint.Style.FILL);
  
  float shaderCx = cx;
  float shaderCy = cy;
  int shaderColor0 = Color.RED;
  int shaderColor1 = Color.BLUE;
  
  MyPaint.setAntiAlias(true);
  MyPaint.setShader(new SweepGradient(
        shaderCx, 
        shaderCy, 
        shaderColor0, 
        shaderColor1));
  
  canvas.drawCircle(cx, cy, radius, MyPaint);
  
 };
 
}

MainActivity.java

package com.example.androiddraw;

import android.os.Bundle;
import android.app.Activity;

public class MainActivity extends Activity {

 @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        MyView myView = new MyView(this);
        setContentView(myView);
    }
    
}

Download the files.