1.对于简单的两个Activity

public class A_activity extends Activity {
             public static A_activity _instance = null;          @Override          protected void onCreate(Bundle savedInstanceState) {                // TODO Auto-generated method stub                super.onCreate(savedInstanceState);                 .....                //重点              _instance = this;          }    }

public class B_activity extends Activity {
                 @Override          protected void onCreate(Bundle savedInstanceState) {                   // TODO Auto-generated method stub                 super.onCreate(savedInstanceState);                 A_activity._instance.finish();           }    }

2.也能够通过ActivityManager

ActivityManager manager = (ActivityManager)getSystemService(ACTIVITY_SERVICE);   manager.restartPackage(packageName);