How to get android context from a reference of interface? -

i have activity instantiate class interface. how can android context within myclass reference interface?

public class testactivity extends activity implements myinterface {      @override     public void oncreate(final bundle savedinstancestate) {         final myclass myclass = new myclass(this);      }      @override     public void onchange() {      } }   public interface myinterface {     void onchange(); }  public class myclass {     public myclass(myinterface myinterface) {        // how context myinterface ???     } } 

public class myclass {     public myclass(myinterface myinterface) {     // context     context context = null;     if (myinterface instanceof context)         context = (context)myinterface;     } } 

if activity (which extends context) implementing myinterface , pass myclass, need cast appropriate type.