Android 在Activity中关闭另一个Activity

比如现在有N个activity a b c d ....
如果在d上关闭activity a

An activity can be shut down by calling its finish() method. One activity can shut down another activity (one it started with startActivityForResult()) by calling finishActivity().

在a里面设置一个静态的变量instance,初始化为this
在D里面,a.instance.finish()

如下面的例子：

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);
.....
_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.也可以通过ActivityManager

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

第一个我已经实践过了，很好用，第二种方法不太理解。