ScreenShot

MainActivity
public class MainActivity extends AppCompatActivity {


    private View main;
    private ImageView imageView;
    Button btn;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        main = findViewById(R.id.main);
        imageView = findViewById(R.id.imageView);
        btn = findViewById(R.id.btn);



        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Bitmap b = ScreenShot.takescreenshotOfRootView(imageView);
                imageView.setImageBitmap(b);
                main.setBackgroundColor(Color.parseColor("#999999"));

            }
        });
    }
}


ScreenShot.java
======================

public class ScreenShot {

    public static Bitmap takescreenshot(View v){
        v.setDrawingCacheEnabled(true);
        v.buildDrawingCache();

        Bitmap b = Bitmap.createBitmap(v.getDrawingCache());
        v.setDrawingCacheEnabled(false);
        return b;

    }

    public static Bitmap takescreenshotOfRootView(View v )
    {
        return takescreenshot(v.getRootView());
    }
}