29 lines
1.7 KiB
Markdown
29 lines
1.7 KiB
Markdown
**Multi-Threaded Work - Running long tasks inside of a GUI**
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This program demonstrates one way of using a combination of Python's Thread
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and Queue objects to implement a GUI that performs work that takes too long
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to directly perform inside of the event loop.
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An example use would be if you have a button that you want to use to start
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some code that will take several seconds to run, then this technique is a
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good pattern to use.
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Take a moment to examine the code dealing with the Thread and the Queue. These
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constructs are nothing to fear as the amount of code that uses them is only a
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handul of lines of code are needed. And they are simple enough that you'll
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be able to understand them.
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***"Thread-safe"*** - This is an important term to consider any time you are using threads in your program. There are 2 things to check out:
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1. You must make sure that the calls you make from your thread are OK to call from a thread
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2. If you are running multiple threads, then the calls you make must be "thread-safe"
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The authors of libraries you are using often tell you if their code is "thread-safe".
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PySimpleGUI code is not thread safe. For the tkinter version (i.e. plain PySimpleGUI versus PySimpleGUIQt), you cannot run PySimpleGUI as a thread. To put that in simpler terms, you cannot make any calls into the PySimpleGUI package from a thread. For example, you cannot call `update` for any of your elements from a thread. This is why you see the updates happening from the main thread only.
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Screenshot:
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<iframe src='https://trinket.io/embed/pygame/8f2aeea67b?start=result' width='100%' height='650' frameborder='0' marginwidth='0' marginheight='0' allowfullscreen></iframe>
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