Android 后台线程弹对话框导致程序崩溃(is not valid; is your activity running)
异常:android.view.WindowManager$BadTokenException: Unable to add window — token android.os.BinderProxy@438e7108 is not valid; is your activity running? 因为使用了AsyncTask 异步线程在线程完成以后的onPostExecute方法里