在ActivityA中关闭还有一个ActivityB

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);