The Widgets do not update Text Instantly
Added by Danish Jalil about 9 years ago
I have set up a Rest API which I am trying to hit from this simple Web App. I am trying to show the text on the screen when I get a response.
In the code that I have attached I am updating the text in the TextArea by calling the setText method. The text only gets updated when I click again on the submit button. Is it because I get the response in another thread that can not update the widgets?
Any help will be much appreciated!
| HelloApplication.txt (4.41 KB) HelloApplication.txt |
Replies (1)
RE: The Widgets do not update Text Instantly - Added by Wim Dumon about 9 years ago
Your assumption is correct: handleRequest is executed in an asynchronous thread, from which you can not just edit the widget tree. There are two steps that you need to resolve the situation: (1) enable server push and push your changes, and (2) you must grab a lock on the widget tree before you modify it, or alternatively use WServer::post() to modify the widget tree (in which case Wt will take care of grabbing the lock).
See documentation of WApplication (section on server push + WApplicationLock) and WServer (about post()). There is also an example (feature/serverpush) that demonstrates this functionality.
I recommend to work with WServer::post(), since it is usually simpler than properly managing the lock.
Best regards,
Wim.