Sorry if this counts as necro, but I was looking for a way to get all the spoiler buttons to expand open at once and I found a real easy method and wanted to add it to this thread.
This creates a bookmark that you click/tap on make it work, called a bookmarklet.
Step1. Save a bookmark. Doesn't matter where or what the bookmark is called.
Step2. Edit the URL location code from whatever it was to the following.
Just copy/paste the code bellow.
javascript

function(){jQuery(document).ready(function(){jQuery('.bbCodeSpoiler-button').click();});})();
Edit: the script shows a frowning face emoji on this site, but it should still copy as ":"
If it doesn't swap it out.
Step3. Save the changes and now on QQ just tap this bookmark to execute the javascript. Works fine on my iPad safari browser.
If copy/pasting the code doesn't work. Search google with this text to find the website I used.
[Tool] How to toggle expand/collapse all spoiler tags easily