Questions tagged [qt]

Qt is a cross-platform application development framework widely used for the development of GUI programs.

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Accessing Hardware-based resources from multiple worker threads

I have a technical application that interacts with different hardware components: measurement devices, sensors, custom hardware. These use dedicated interfaces like USB, serial ports, TCP/IP ...
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1 answer
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Plugin system design core component access: Common practice?

I wonder how to design a good plugin architecture in C++/Qt. The main concern I have is about dependency injection vs globals when it comes to the core components. Plugins should have access to ...
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User proof network app with distant database [duplicate]

I’m currently writing a software for my company (3rd world country), and I wanted it as simple as possible to install and maintain, so I started with Qt and no server app beside the database, (MariaDB ...
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1 answer
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Using the same function in two classes? [closed]

I have two classes for making pyqt5 windows. Inside class one I have a button with a function it is connected to. Class One: from PyQt5 import QtGui, QtWidgets, QtCore from PyQt5.QtWidgets import ...
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Designing a library API to allow for interactivity

The application I'm currently working on is deeply coupled to the UI framework in use (Qt at the moment). I would like to separate the UI-specific code from the rest as much as possible, with the goal ...
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3 answers
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When is Model/View/Controller Too Much?

To preface, I work at a place that I feel misunderstands and overuses MVC, but I also recognize that maybe it's me who doesn't understand it. I'm used the model/view exclusively within the context of ...
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1 vote
1 answer
490 views

Best way to access (grand grand) parent element in gui

I'm creating a multi window gui program, in c++ with Qt Widgets. I do have many custom gui elements, which usually are c++ classes inherited from QWidget or other Qt elements. When foo is the main ...
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fake filesystem for unit tests

I am writing an application in c++ and Qt5. It would be very convenient for me to create a virtual file system so I can unit test code working on files. I have found that in Qt4 there was a ...
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2 votes
2 answers
330 views

Design tips for waiting for a user input while working on another thread

I am working on an application with multiple threads (using Qt, C++). One of this threads is designed to execute a batch of operations like reading/writing from/to files as well as creating new ones. ...
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2 votes
2 answers
107 views

Processing user commands and parameters

I'm writing a GUI application which needs the facility for users to interact with the system and execute tasks via a sort of command line interface. The user will type commands in a text box, with ...
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0 answers
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How to organize an App composed of Features in Qt?

When developing a somewhat larger application, with 3-4 screens or so, what is the most common way to organise the code? I've read that organize-by-feature trumps organize-by-type, so I was ...
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How to design a PyQt/Pyside2 application to use the MVC pattern with the Qt MV pattern?

The context: I created a PySide2 app to remote control a pyhsical product. The device is interfaced with a driver to get and set it's overall state (state machine with nested and parallel states) and ...
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1 vote
2 answers
989 views

How can I emulate Signals and Slots found in Qt, to Javascript / Typescript Classes?

Ive brought this up with other developers, and they say while there is no obvious way forward, it seems that they all have an idea of how to go about it. Is there any way I can implement signals and ...
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Which components of an HTML Element, can I assume will be static over the course of its lifetime?

This is a question for people who are familiar with how HTML typically is built and behaves on webpages. Backstory and requirements I am building an HTML tracker with a C++/Qt backend. I am trying ...
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1 vote
4 answers
292 views

How would I add up enumerator values such that any combination provides a unique number?

Backstory (You can skip) I am writing a pronunciation library for irregular words. Take something like the following: T1E1s // tee one E one es | tee one E ones 1994-1995// 1994 (minus|dash|to|) ...
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1 vote
1 answer
210 views

Architecture/Design for Hardware Control Software

I'm currently working on the control software for a system that includes a lot of user controllable hardware and also has many configurations. Configurations in this context refers to a specific ...
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2 votes
1 answer
3k views

Do I need to make my code open source or buy a license? [closed]

I want to develop a GUI in python for my company in order to sell it to the customer. Being fresh from the university where I used pyQt, I promptly started programming using that library, just to ...
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1 vote
2 answers
930 views

Organizing and Creating a Custom Qt Widget

I am looking to create a digital Rolodex to keep track of contacts in Qt 5.9 and am uncertain how to efficiently create custom widgets. Examples online like the classic clock example show to ...
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2 votes
3 answers
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In c++, is there a way inside a function block, to execute cleanup code after the value has been returned?

Backstory (You can skip) I am building an API for managing Files and Directories in a consistent manner across a project. This is for deduplication and consistency when performing a task, and in this ...
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1 vote
0 answers
169 views

Save data from multiple Qt components scattered around multiple QML files

I would like to save the current "value" property of several components (e.g. a Slider) as a configuration profile when the user clicks on the Save button in my application. However, the Save button ...
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1 vote
2 answers
973 views

Should I always allocate QObject and derived classes to the heap?

I was in #Qt irc channel, and I showed a small snippet of my code in a style that I heavily rely upon. It looks like this: /* Get Reply from Server */ QPointer<QNetworkReply> reply; { ...
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1 vote
1 answer
220 views

How to understand and design functions with enumeration arguments that work in tandem with bitwise operators in C++ and Qt?

In the C++, there are 6 bitwise operators: Symbol Operator & bitwise AND | bitwise inclusive OR ^ bitwise XOR (eXclusive OR) << left shift >> right shift ~...
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1 answer
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How to manually model a UML activity Diagram to JSON with Qt C++?

Suppose I have a kind of UML activity diagram with 1-n forks and joins. The assignment of the individual nodes relative to each other is defined by an XML relationship table via UUIDs where each ...
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-3 votes
1 answer
359 views

QElapsedTimer hasExpired() - Is it one msec off?

Here is a a part of the documentation of Qt's QElapsedTimer: bool QElapsedTimer::hasExpired(qint64 timeout) const Returns true if this QElapsedTimer has already expired by timeout milliseconds (...
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1 vote
1 answer
440 views

Remove duplicated switch statements caused by not knowing type at compile time of opencv matrix?

I have a situation that occurs 5 times in my code, and continues to grow. Basically I have the same switch statement structure every time I need to perform an operation that involves my matrix and ...
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-2 votes
1 answer
1k views

What Is the Best (Conventional) Way to Format Code for PyQt5

I was looking into PyQt5 for one of my side-projects and would really like to get to learn it better. However, I wasn't sure how to correctly format the code. I've seen tutorials do class definitions ...
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3 votes
3 answers
438 views

How to separate serialization, visualization and computation from GUI editable code objects?

This might be an X Y problem, but here's my situation. I've got a QT5 C++ code base whose task it is to allow for the configuration of a "process chain". A "process chain" here means a list of ...
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11 votes
5 answers
11k views

Moving from Qt/C++ to C#/WPF - Productivity Gain?

I created a small Desktop application (approx 15000 lines of code, so not that large) written in C++/Qt. This is non-commerical, just a hobby project and I am coding on my free time. The larger the ...
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2 answers
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What is the safest practice in handling QWidget pointer lifespan in a QObject oriented environment?

Consider the following constructor: NetworkTools::NetworkTools(QObject *parent) : QObject(parent) { view = new QWebEngineView(); view->setParent(parent); // Produces an error, shown below. ...
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2 votes
3 answers
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Architecture of gui application

I am writing gui application. I want to implement following structure: project tree with nodes of different type and behavior (i.e. when right clicking or selecting there can be different menu ...
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2 votes
1 answer
196 views

Reusing UI elements between two different QWidgets

I am writing a utility in C++ with Qt which communicates with an embedded device. The program was originally going to be used to just plot data from the device, but a new requirement has been added (...
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3 votes
1 answer
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When writing a Qt application is good practice to ALWAYS prefer Qt function implementations, data types, and classes when they are available?

I'm just starting out with Qt and I really want to try and keep my application as separated from Qt as possible in case I decide to use a different toolset later, but at the same time don't want to ...
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1 vote
2 answers
405 views

How should I structure my C++ project to allow for starting, stopping, and pausing my program?

TL;DR: How should I structure my C++ project to allow for starting, stopping, and pausing my program? Overview: I am designing an application that needs to allow users to start, pause, and stop the ...
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  • 129
2 votes
1 answer
291 views

Using Qt in Open Source App that Communicates with Closed Source Hardware

Preface I'm having trouble determining if I can use the Qt framework for developing a cross platform desktop app. Situation The app is open source, and the libraries it uses are also open source. ...
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1 answer
109 views

For Qt, or C++, do modern standards or practices exist for designing Run Configuration files for your programs? [closed]

Backstory I am building a daemon that is to be run in the background on systems based on X11. As of right now, the settings are hardcoded, and that obviously needs to change. As such, I plan to ...
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0 votes
1 answer
605 views

In Qt or C++, is there a good means for creating a switch with dynamically generated cases, or should I just use a for loop (or something else)?

Presume this situation: Max Number of 256 key slots. Key slots are defined by a struct, and a variable for each (256) has to exist. User defines which keys slots are active at initiation (in my ...
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-1 votes
2 answers
723 views

Interaction between model and self-modifying data in Qt MV

I have a tree structure that represents a system of devices that are connected to the PC via serial port. In a way, this structure was inspired by tree model example in Qt and I think that helps to ...
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5 votes
2 answers
2k views

What can I infer from someones code when they use direct initialization with Curly Braces as opposed to Parenthese?

Up until now, I have been initializing most of my variables as such: const QString foo("bar"); Which from my newfound understanding, is known as direct initialization. (http://en.cppreference.com/w/...
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0 votes
1 answer
229 views

Windows Qt5-based app porting to Linux

I'm here today, because I'd like to ask you a question about porting application built with Qt5 to linux. I have been asked to port this application to linux, I don't yet have the source code, but I ...
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2 votes
2 answers
2k views

Events fired when widgets are updated programmatically

In the GUI application I'm working on I have a number of custom (composite) widgets that I've created, with each widget having an update_gui function where I access my SQLite database so I can fill in ...
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-1 votes
1 answer
2k views

Is it required to disclose source code for custom Qt software? [closed]

I was hired to develop a custom Qt application for a customer, but I'm concerned about the licensing. My software will not be publicly distributed and it is going to be used exclusively by this ...
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  • 115
1 vote
3 answers
634 views

How to handle custom metadata in XML?

Backstory I have an XML type document (SSML, which is used forText-To-Speech), which will be used to generate audio files when ssh transferred to a remote server. As such, I will need to include ...
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1 vote
1 answer
145 views

Static link GUI project as dynamic library

My app has 2 projects: logic.dll and GUI.dll. Currently, its size is 1MB, but the whole app's size is 60MB+ due to the dependency dlls. I've read about QT-LGPL license and know that to keep my app ...
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7 votes
2 answers
506 views

How to treat in-house libraries

I am facing problems structuring projects and libraries. In the company I am working for I often see, that things would be more maintainable and less error prone, if we could extract common code and ...
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  • 187
6 votes
1 answer
152 views

Database Model description using constants

I want to create a class with static constants which are used whenever a part of an application want to access the database in any way. This way I want to remove all magic numbers and string inside my ...
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0 votes
1 answer
383 views

What is the proper way to track my build versions in Qt?

Basically what I need in my project is a number of some sort that iterates itself every time I build my project, and that I can output by my program. So for example, when generating audio, I need to ...
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0 votes
0 answers
148 views

Qt Naming Schemes for returns of boolean member variables: enabled(); vs isEnabled(); ?

In building my classes, I have noticed that I have not been very consistent about naming my boolean returns. In Qt; I notice that many of their classes use the is prefix, but checking their coding ...
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  • 3,319
0 votes
1 answer
181 views

How to play audio samples while generating them

I am trying to write a simple live sine wave generator from scratch in Qt. I try not to use any external APIs like ASIO or VST. And I want to generate new audio while playing. (As opposed to the Qt ...
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  • 135
3 votes
2 answers
2k views

Not understanding the concept of how to make my GUI application

I am making a program that primarily deals with heavy data mining and analysis. It is primarily a back-end type algorithm, with no GUI elements or console windows seen as it runs. Occasionally though, ...
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2 votes
2 answers
2k views

In Qt or C++, how should I check whether my `int` variable has been defined?

Short Problem: How should I check if integers are undefined, just as I can check QStrings for having NULL values? Backstory: This is my coding style when I am trying to avoid overloading my ...
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