AlertDialog显示错误 Unable to add window token null is not for an application

在listView的onItemClick函数中显示一个AlertDialog，出现如下错误

08-07 21:26:43.506: ERROR/AndroidRuntime(9390): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

08-07 21:26:43.506: ERROR/AndroidRuntime(9390): android.view.WindowManager$BadTokenException: Unable to add window -- token null is not for an application

后google解决，代码中显示语句如下

AlertDialog imageDialog = new AlertDialog.Builder(context).setTitle("状态操作").setItems(items, listener).create();
imageDialog.show();

AlertDialog imageDialog = new AlertDialog.Builder(context).setTitle("状态操作").setItems(items, listener).create();
                imageDialog.show();

其中context为在OnCreate中

context = getApplicationContext();

context = getApplicationContext();

得到，而AlertDialog创建语句

public AlertDialog.Builder (Context context)

public AlertDialog.Builder (Context context) 

中，不能使用 getApplicationContext()得到的context，而必须使用Activity，所有语句修改为

AlertDialog imageDialog = new AlertDialog.Builder(Activity.this).setTitle("状态操作").setItems(items, listener).create();
imageDialog.show();

AlertDialog imageDialog = new AlertDialog.Builder(Activity.this).setTitle("状态操作").setItems(items, listener).create();
                imageDialog.show();

其中的Activity为当前Activity的名称

参考：

http://blog.csdn.net/yimo29/article/details/6004782