I set the color to red , and after that I want to set the color again back to default, but I do not know what is default color, does anyone knows ?
You can save old color and then use it to restore the original value. Here is an example:
ColorStateList oldColors = textView.getTextColors(); //save original colors
textView.setTextColor(Color.RED);
....
textView.setTextColor(oldColors);//restore original colors
But in general default TextView
text color is determined from current Theme applied to your Activity
.