Home PHP C# C++ Android Java Javascript Python IOS SQL HTML Categories

Asynchronous call from QML to Python with callback

There is no indication from the documentation that QJSValue is thread safe. This page indicates the classes that are re-entrant or thread safe are marked as such in the documentation. However, there is no mention of the word thread on the page for QJSValue.

As such, I would suggest you make sure that your callback is only called from the main thread. Obviously, you are still going to want to put your long running task in a thread, so I would suggest using something like QCoreApplication.postEvent() to send an event from your Python thread to the main thread, which will then call your callback function.

Note: I've wrapped calls to QCoreApplication.postEvent for PyQt4 here. If you need help understanding how to use the QCoreApplication.postEvent method, you can probably adapt it to work with PyQt5 as well.

Categories : Python

Related to : Asynchronous call from QML to Python with callback
python rotating file handler callback
There's not really a callback, but you can easily subclass the RotatingFileHandler and override your own "rotation", by implementing the doRollover method: MyFileHandler(RotatingFileHandler): def doRollover(): # invoke the superclass' actual rotation implementation super(MyFileHandler, self).doRollover() # start doing your own tasks # ...

Categories : Python
A function that takes a callback and creates a new version of the callback that can only be called once. Javascript
Your function once does not return anything, and your function call does not call anything. Make it function once(func) { var hasActionBeenCalled = false; return function() { if (!hasActionBeenCalled) { hasActionBeenCalled = true; return func.apply(this, arguments); } } } For garbage collection, I'd recommend to do function once(func) {

Categories : Javascript
Asynchronous operation in router.use
Sure it will as long as you use next() properly Example: router.use('/', function(req, res, next) { somethingAsync(function(err, result) { if(err) return next(err); // Do whatever return next(); }); }); The router stack is called in the order routes are added to it. Calling next() calls the next route in the stack matching the provided path. Calling next(someError) calls the

Categories : Node Js
Why does this file reading is asynchronous ?
The third argument to open is whether the XHR object should work asynchronously (true) or synchronously (false). The latter has the negative effect of locking up the UI of the browser while the request is being handled, so is best avoided whenever possible (and it's essentially always possible).

Categories : Javascript
Asynchronous function calls in Qt
How can I make the second call getSearchList wait? You don't! Instead, just move any code that expect the XML file to be downloaded into the fileIsReady() slot that you've already defined. That way your program won't lock up while it's waiting for the download to complete (which is the entire point of asynchronous programming.)

Categories : C++
Recently Add
Unable to Delete and redraw or Draw over plot axes based on PYQT widget state change
Generate, fill and plot a hexagonal lattice in Python
Getting a decorator with args to work with method: self does not exist
Is this function correct?
kivy adding variables to the root widget
Pandas: Generate a histogram/pivot against timeseries data
bash wrap a piped command with a python script
Selecting a combo box using selenium webdriver xpath
How to check how many calls left in AlchemyAPI? python
sklearn.ensemble.AdaBoostClassifier cannot accecpt SVM as base_estimator?
Sklearn Linear Regression - "IndexError: tuple index out of range"
How can I keep an object selected in the outliner after physically deselecting it in the 3d view?
Limiting results with Jinja (Python)
Python Flask - Which file is used to log?
ros python publisher/subscriber
Get spline fit residual from scipy.interpolate.splprep()
A linker error of Boost.Python in Visual Studio 2008
access parent methods in python
Python retreive DayOfWeek as integer
Async insertAll requests using python-api-client
django modelForm filter isn't effective?
Many numpy array manipulations in one array
How can I unit-test a method without instantiating the class?
base.html can't access {% if user.is_authenticated %}
How to cope with diacritics while trying to match with regex in Python
Data is missing after using @validate with Schema
Find out where a process writes to
kivy - getting a spinner to remember its selection
Regular expression is not working
Django - Get a QuerySet of Months and the amount of expense
© Copyright 2017 Publishing Limited. All rights reserved.