How to change background color via java?

Question

Hello I'm a newbie in android development and I am looking forward a way to change the background color.

Here is my code:

super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// View layout = new View(this);
// layout.setBackgroundColor(android.R.color.holo_blue_light);
// View root = layout.getRootView();
// root.setBackgroundColor(android.R.color.holo_green_dark);
View view = this.getWindow().getDecorView();
view.setBackgroundColor(R.color.red); 

Answer 1

The problem is with the syntax view.setBackgroundColor(R.color.red);
Try:

view.setBackgroundColor(Color.RED); 

Answer 2

view.setBackgroundResource（R.drawable.example）;

Answer 3

used this :-

 view.setBackgroundColor(ContextCompat.getColor(context, R.color.color_name))

This will choose the Marshmallow two parameter method or the pre-Marshmallow method appropriately.