This establishes a safe bridge of communication between threads. This means that you can execute code in a thread as a response to a signal emitted in the same thread or in another thread. emit values, which are then picked up elsewhere in your code by slot functions which have been linked with. Qt provides the signals and slots framework which allows you to do just that and is thread-safe, allowing safe communication directly from running threads to your GUI frontend. Note: if an update takes a long time the code will have to be organised in a way that does not block the mainloop by keeping the blocking part in a separate thread from the actual call to the gui methods. PyQt’s signals and slots mechanism provides a robust and safe way of communicating with worker threads in a GUI application. This allows you to get feedback on the progress of worker threads and update the GUI accordingly, send data to your threads, allow the users to interrupt the execution, and so on. Even if the Qt class is reentrant, you cannot share access to a Qt object between threads unless the Qt documentation for that class explicitly states that instances are thread safe. anything that subclasses QWidget or similar). You cannot create or access a Qt GUI object from outside the main thread (e.g. To demonstrate multi-threaded execution we need an application to work with. The following code will work with both Python 2.7 and Python 3. PyQt (via Qt) provides an straightforward interface to do exactly that. The solution is simple: get your work out of the GUI thread (and into another thread). This thread will update our text field with scraping info from the source that is signed in the line edit field. Related to PyQt, QThread class is commonly used for splitting of tasks into multiple threads to increase the speed of the GUI application, because a large number of tasks in one thread make the application slow and frozen.

Qt update gui from different thread