If your class is non-activity class, and creating an instance of it from the activiy, you can pass an instance of context via constructor of the later as follows:
class YourNonActivityClass{
// variable to hold context
private Context context;
//save the context recievied via constructor in a local variable
public YourNonActivityClass(Context context){
this.context=context;
}
}
You can create instance of this class from the activity as follows:
new YourNonActivityClass(this);