Want to make a pop up message for the Error on Android

Want to make a pop up message for the Error on Android

This is the method that i want to add popup message. If the result set
contain "404" i want to display a message. I can`t use Toast Here because
this is not have written on any Activity Context.
protected void onPostExecute(String result) {
//To make a popup notification when it is a Not Found Location
if(result.contains("404")){
return;
}
super.onPostExecute(result);
if (baseFragment != null) {
if (isMainTask) {
baseFragment.onTaskFinished(result);
} else {
baseFragment.onSubTaskFinished(result);
}
}
}