msl.qt.threading module

Base classes for starting a process in a new QThread.

class msl.qt.threading.Worker(*args, **kwargs)[source]

Bases: QObject

Process an expensive or blocking operation in a thread that is separate from the main thread.

You can access to the attributes of the Worker as though they are attributes of the Thread.

The *args and **kwargs parameters are passed to the constructor of the Worker when the start() method is called.

Example

See SleepWorker for an example of a Worker.

process()[source]

The expensive or blocking operation to process.

Attention

You must override this method.

class msl.qt.threading.Thread(worker)[source]

Bases: QObject

Moves a Worker to a new QThread.

Parameters:

worker – A Worker subclass that has not been instantiated.

Example

See Sleep for an example of a Thread.

finished

A Signal that is emitted when the thread is finished (i.e., when process() finishes).

__getattr__(item)[source]

All other attributes are assumed to be those of the Worker.

error_handler(exception, traceback)[source]

If an exception is raised by the Worker then the default behaviour is to show the error message in a critical() dialog window.

You can override this method to implement your own error handler.

Parameters:
is_finished()[source]

Whether the thread is finished.

Returns:

bool – True if the thread finished otherwise False.

is_running()[source]

Whether the thread is running.

Returns:

bool – True if the thread is running otherwise False.

quit()[source]

Tells the thread’s event loop to exit.

start(*args, **kwargs)[source]

Start processing the Worker in a QThread.

The *args and **kwargs are passed to the constructor of the Worker class.

stop(milliseconds=None)[source]

Calls quit() then wait().

wait(milliseconds=None)[source]

Wait for the thread to either finish or timeout.

Parameters:

milliseconds (int, optional) – The number of milliseconds to wait before a timeout occurs. If None then this method will never time out and the thread must return from its run method.

Returns:

bool or None – True if the thread finished, False if the thread timed out or None if the thread is not running.

worker_connect(signal, slot)[source]

Connect a Signal from the Worker to a Slot.

This method is intended to be called before a worker thread starts. Although, you can still call this method when a worker thread is running, it is easier (fewer characters to type) to access the attributes of a Worker as though they are attributes of the Thread.

Parameters:

  • signal (str, Signal or SignalInstance) – The signal to connect the slot to. If a str, then either the name of a class attribute of the Worker or the name parameter that was used in the Signal constructor.

  • slot – A callable function to use as the Slot.

worker_disconnect(signal, slot)[source]

Disconnect a Slot from a Signal of the Worker.

This method is intended to be called before a worker thread is restarted. Although, you can still call this method when a worker thread is running, it is easier (fewer characters to type) to access the attributes of a Worker as though they are attributes of the Thread.

Parameters: