Pyqt refresh gui

Please share with friends and colleagues! PyQtGraph uses the Qt vector-based QGraphicsScene to draw plots and provides a great interface for interactive and high performance plotting. However, there is another plotting library for Python which is used far more widely, and which offers a richer assortment of plots — Matplotlib.

If you're migrating an existing data analysis tool to a PyQt GUI, or if you simply want to have access to the array of plot abilities that Matplotlib offers, then you'll want to know how to include Matplotlib plots within your application. Many other Python libraries — such as seaborn and pandas — make use of the Matplotlib backend for plotting. These plots can be embedded in PyQt5 in the same way shown here, and the reference to the axes passed when plotting.

There is a pandas example at the end of this tutorial. The following examples assume you have Matplotlib installed. If not you can install it as normal using Pip, with the following —. The following minimal example sets up a Matplotlib canvas FigureCanvasQTAgg which creates the Figure and adds a single set of axes to it.

This canvas object is also a QWidget and so can be embedded straight into an application as any other Qt widget. In this case we're adding our MplCanvas widget as the central widget on the window with. This means it will take up the entirety of the window and resize together with it. The plotted data [0,1,2,3,4], [10,1,20,3,40] is provided as two lists of numbers x and y respectively as required by the.

Plots from Matplotlib displayed in PyQt5 are actually rendered as simple bitmap images by the Agg backend. The effect of this architecture is that Qt is unaware of the positions of lines and other plot elements — only the x, y coordinates of any clicks and mouse movements over the widget. However, support for handling Qt mouse events and transforming them into interactions on the plot is built into Matplotlib.

This can be controlled through a custom toolbar which can be added to your applications alongside the plot. In this section we'll look at adding these controls so we can zoom, pan and get data from embedded Matplotlib plots. First we import the toolbar widget from matplotlib. We create an instance of the toolbar by calling NavigationToolbar with two parameters, first the canvas object sc and then the parent for the toolbar, in this case our MainWindow object self.It even covers creating an installer for your app.

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PyQt5 refers to the most recent version 5 of Qt. You may still find the occasional mention of Py Qt4 on the web, but it is old and no longer supported.

An interesting new competitor to PyQt is Qt for Python. Its API is virtually identical. It's backed by the Qt company, and thus likely the future. We use PyQt here because it is more mature. The best way to manage dependencies in Python is via a virtual environment.

A virtual environment is simply a local directory that contains the libraries for a specific project. This is unlike a system-wide installation of those libraries, which would affect all of your other projects as well.

To create a virtual environment in the current directory, execute the following command:. To activate the virtual environment on Windows, run:. You can see that the virtual environment is active by the venv prefix in your shell:.

The reason why we're using version 5. This version is guaranteed to work. Besides this subtlety — Congratulations! You've successfully set up PyQt5. Time to write our very first GUI app! With the virtual environment still active, start Python. We will execute the following commands:. Next, we create a QApplication with the command:.

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Many parts of Qt don't work until you have executed the above line. You will therefore need it in virtually every Py Qt app you write. The brackets [] in the above line represent the command line arguments passed to the application. Because our app doesn't use any parameters, we leave the brackets empty.

The last step is to hand control over to Qt and ask it to "run the application until the user closes it". This is done via the command:.

If all this worked as expected then well done! Everything you see in a Py Qt app is a widget : Buttons, labels, windows, dialogs, progress bars etc. Like HTML elements, widgets are often nested.

pyqt refresh gui

For example, a window can contain a button, which in turn contains a label. You can download the code for the app shown in the screenshot hereif you are interested. Like the example above, your GUI will most likely consist of multiple widgets.By using this site, you agree to our updated Privacy Policy and our Terms of Use.

Manage your Cookies Settings. Join Now login. Ask Question. I want to draw some lines on a widget. This works ok, but when I want to redraw, the old lines are still there. How do I clear or refresh the widget, so I can draw a new set of lines? Code snip below. Jul 18 ' Post Reply.

Share this Question. Diez B.

pyqt refresh gui

Peter wrote: I want to draw some lines on a widget. Call erase on your widget. Or redraw a rectangle yourself. Roggisch wrote: Call erase on your widget. Thanks, that works fine. Peter wrote: Diez B. Peter wrote: Thanks, that works fine. So there is no need to have a separate documentation and other resources. The erase I looked up in the qt standard documentation.Welcome to LinuxQuestions. You are currently viewing LQ as a guest.

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Are you new to LinuxQuestions. If you need to reset your password, click here. Having a problem logging in? Please visit this page to clear all LQ-related cookies. Introduction to Linux - A Hands on Guide This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter. For more advanced trainees it can be a desktop reference, and a collection of the base knowledge needed to proceed with system and network administration.

This book contains many real life examples derived from the author's experience as a Linux system and network administrator, trainer and consultant. They hope these examples will help you to get a better understanding of the Linux system and that you feel encouraged to try out things on your own. Click Here to receive this Complete Guide absolutely free. Hi all, I'm trying to program a simple graphical display interface with PyQt4 and am encountering a problem with regards to refreshing the content of the widgets.

The script gets the output from a command and for each 'line' which is a node in a cluster outputs what VMs are running on it. This is the basis of it all. Everything works, the loop, the timer, getting the information displayed. On the second run and consequent runs I can clearly see that the contents get displayed 'on top' of the previous one and so on.

Can someone take a look at my code and tell me what I'm missing? I've been through Google over and over again and haven't find any solution yet. Please keep in mind that these are my first baby steps in attempting to program in PyQt4.

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Which you add to and forget to remove from as program runs? Yes, there's a better way to do it. Just replace that whole setup with a QTableWidget. Also, QLabels have a setText method, so you could have just completely filled the grid with QLabels and just manipulated their text properties, instead of trying to add QLabels in later.

The TableWidget is obviously better though. Last edited by dugan; at AM. Find More Posts by dugan. Hi, Thanks for your reply. Mind you, I'm no programmer, just a humble system administrator so I was quite exited to get this working in two days. I just added a stylesheet with some basic coloring to the QWidget and strange enough, now it updates without problems and without 'overwriting' the previous 'version'.

I'll take a look at how QTableWidget works and give it a try. Learning lots of new stuff every day. Thanks for pointing to 'the better way'. Since apparently using a setStyleSheet kind of solved my problem, without me knowing why, I'm marking this thread as solved but welcome any 'real' solution.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Seen much posts about threading and qtimer but not really understand it for my GUI. So i want to update everything or just want to add the new one and if the call hang up it have to be deleted. You should init your layout before invoke self. Learn more. Asked 2 years ago.

Active 2 years ago. Viewed 3k times. Marcel Marcel 1 1 1 silver badge 1 1 bronze badge. Active Oldest Votes. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.

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pyqt refresh gui

The Overflow How many jobs can be done at home? Featured on Meta.I've written about Getting started with PyQt in one of my previous blog posts, and the post covers the basics of getting Qt Designer and PyQt in general up and running - check it out if you haven't already.

However an important thing missing from that post is threading and how to do it in PyQt. If you're just looking for final commented code and not a step by step tutorial for beginners click here. Note: This tutorial assumes you're at least familiar with the things mentioned in the previous "Getting started with PyQt" tutorial, and that you have basic understanding of what threads are and how they work. In this post I'll write a simple app that fetches top posts from few different subreddits subsections of reddit.

The design will be simple as that's not the main point of the post, and the backend will only use modules built into python and PyQt of course to reduce number of 3rd party dependencies required.

And you can find the Qt Designer. Since this part isn't the focus of the tutorial I will skip any exception checking etc and just assume that the response from reddit will be valid. The code for fetching the top posts from a list of subreddits is:. The reason for the time. The GUI code will be set up just like in the previous tutorial I wrote. If you don't understand what some parts of it are doing check out that blog post before continuing.

Okay, now that we've seen what kind of issues we'll have if we don't use threads with PyQt and we do something that takes time on the main thread we'll start re-writing the code above with help of a QThread class. We will also enable user to stop the thread that has already been started by clicking on the "Stop" button. The QThread we'll be using in this tutorial is a simple and the whole thing is written like this:.

Also you don't call the run method itself, but instead you call start - calling run directly in some cases can also freeze your main thread depending on how the run method is implemented in your thread. So the example usage of that thread above inside for example QMainWindow class would be:.

You can use something like isRunning method to see whether the thread is still running in your code. Most of the time you'll just be using these, which are all self explanatory: quitstartterminateisFinishedisRunning.

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QThread also has these signals which are useful: finishedstartedterminated. The process of moving the reddit code into a QThread is pretty simple, and besides some changes in the run method the main part of the code stays the same.

Another small difference is that we'll pass a list of subreddits upon thread instantiation and then assign it to a instance variable which we'll use in the run method. We also don't need to use the time.

It's pretty self explanatory and the way we'd use that is by first making a list of subreddit names to pass to the thread and then calling it from the main UI code like this:. That's it. The code will run in the background on a separate thread than the main UI one and will fetch all top posts from the list of subreddits specified, however it will not update any UI elements and will give no feedback to the user, which is not you want to have more often than not.

However we can't simply say: self. Since we have all the code running properly in background we need to get the data such as post title to our main UI thread so that we can update the appropriate UI elements such as the progress bar and the list of fetched items. We'll first start off with just notifying the user when all the posts have been fetched by using only built in signals that every QThread instance has.Many people have been asking how they can add a button so that their tkinter GUI can refresh itself.

The first time I wanted to add a refresh button, I thought this was almost impossible because everyone thinks it's not something python has to offer. But I can show you how I managed to add a refresh button into my python code.

I am being tempted to think I'm the only one to discover this trick, so if you're going to use it anywhere, don't forget to thank me. This is super easy! Here's how I managed to do it, 1. First create your first tkinter code with a refresh button in it. Just for the sake of example, let's use the datetime function to see if the time changes everytime we click on the refresh button.

If the second changes per click, it means we have successfully created our refresh button. Save the file as file. Now your tkinter has to refresh itself when you click on it. Do not hesitate to Comment and ask your questions below and I'll try to answer them all.

Good luck with your coding experience! If you are using python 3. TclError: can't invoke "destroy" command: application has been destroyed.

Python GUI with Tkinter - 1 - Introduction

I want to refresh the window without the button press. How do I do that? In case if I package this using pyinstaller, I need to have the python installed and also the. Is there any other alternative, you can suggest please. To use servlets and JSP, we either need eclipse or netbeans.

How to add a refresh button in Python Tkinter GUI

I prefer netbeans and in this tutorial we'll see how to set up servlets an Aenean sollicitudin, lorem quis bibendum auctor, nisi elit conseat ipsum, nec sagittis sem nibh id elit. Duis sed odio sit amei. Powered by Blogger. Tags : python. Newer Post.

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Unknown June 28, at AM. Geleta Jabessa June 29, at AM.


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