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Questions tagged [qt]

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

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1 answer
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Is it a good approach to encapsulate View and Model inside a dedicated Widget?

Lets say you have a ItemView and a ItemModel. Would it make sense to have a ItemWidget encapsulating those two, so code using ItemWidget don’t have to deal with ItemView and a ItemModel specifics? ...
0 votes
0 answers
44 views

Setting Dependency Design

Hello I'm currently designing an GUI application who's main job is to update and display settings and some other data. For context, I'm using QT framework. I'm starting to refactor the settings ...
0 votes
0 answers
25 views

3 QAbstractListModels versus 1 QAbstractItemModel

This is a simplified representation of the existing data structure I have in my code (The actual data structure is composed of classes), the data of which I need to display and modify via multiple ...
1 vote
2 answers
2k 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 ...
13 votes
4 answers
4k views

Merits of copy-on-write semantics

I am wondering what possible merits does copy-on-write have? Naturally, I don't expect personal opinions, but real-world practical scenarios where it can be technically and practically beneficial in a ...
1 vote
0 answers
201 views

Is it preferable to embed ".qm" translation files with Qt Resource System or bundling it with PyInstaller?

I'm learning PyInstaller for deploying Python applications, more specifically, applications developed with PyQt5. As far as I understand, it's possible to bundle application data (or "resources&...
0 votes
1 answer
112 views

What information should one infer from a class header that marks its constructor explicit?

If a class is written well, you should be able to gleam all relevant information about the class simply by looking at its header. If one sees that the constructor is marked explicit: What should one ...
0 votes
2 answers
308 views

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 ...
2 votes
1 answer
3k views

Common Qt Producer/Consumer Example: What is the point of multithreading here?

While trying to figure out how to implement a Producer/Consumer Queue in Qt, I stumpled upon several SO answers, blogs and sites linking to this site: You're doing it wrong... I got the point of this ...
0 votes
1 answer
223 views

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 ...
13 votes
3 answers
22k views

Are Nested Static Library dependencies possible?

I am working in QT . Can a static library depend on another static library?(Static Lib is made by linking another static lib) If yes, is it possible that after linking to lib2, the generated lib(...
0 votes
0 answers
30 views

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 ...
1 vote
2 answers
2k 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 ...
0 votes
1 answer
2k views

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 ...
0 votes
1 answer
96 views

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 ...
1 vote
3 answers
280 views

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 ...
11 votes
5 answers
14k 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 ...
224 votes
14 answers
327k views

Why aren't more desktop apps written with Qt? [closed]

As far as I know and have understood in my experience with Qt, it's a very good and easy to learn library. It has a very well designed API and is cross-platform, and these are just two of the many ...
5 votes
3 answers
3k views

I want to overload a function with the same type parameter; what should I do?

I'm creating an API, and I want to overload a function for strip: QString MyClass::strip(); QString MyClass::strip(QRegularExpression open); QString MyClass::strip(QRegularExpression close); QString ...
-1 votes
2 answers
766 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 ...
8 votes
1 answer
1k views

Should I build undo stack in model or its wrapper?

I am building an application (Python/PyQt). The first-order item will be a tree view/model with many helper functions to add new items, move them around in the tree, etc.. Then I will have a main ...
9 votes
4 answers
3k views

What are the dangerous corners of Qt? [closed]

There's nothing perfect under the sun. Qt is no exception, and it does have limitations: we can't use pixmaps in a thread other than GUI, we can't use QImage with 16-bit-per-channel image format, etc.....
0 votes
1 answer
3k views

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 ...
2 votes
2 answers
730 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. ...
2 votes
2 answers
138 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 ...
1 vote
0 answers
68 views

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 ...
1 vote
0 answers
635 views

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 ...
2 votes
2 answers
2k 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 ...
0 votes
0 answers
49 views

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 ...
1 vote
4 answers
716 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|) ...
1 vote
1 answer
330 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 ...
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 ...
3 votes
3 answers
557 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 ...
2 votes
3 answers
511 views

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 ...
1 vote
0 answers
225 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 ...
1 vote
2 answers
2k 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; { ...
1 vote
1 answer
345 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 ~...
0 votes
1 answer
489 views

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 ...
-3 votes
1 answer
468 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 (...
4 votes
2 answers
2k views

Design pattern for fetching data in chunks

I am creating Qt application that uses database with huge amount of data to draw some charts. Fetching data from the database is time consuming, so is blocking the application thread or worker thread ...
1 vote
1 answer
518 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 ...
7 votes
3 answers
6k views

Is it good practice to have your C++/Qt functions always check all its arguments for null values?

Backstory While developing with Qt Signal/Slots, I came across a few segmentation faults that had me puzzled as to what was causing it. Eventually I figured out that you could actually pass a slot ...
3 votes
6 answers
2k views

In C++ Good reasons for NOT using symmetrical memory management (i.e. new and delete)

I try to learn C++ and programming in general. Currently I am studying open source with help of UML. Learning is my hobby and great one too. My understanding of memory allocation in C++ is that it ...
-1 votes
1 answer
2k 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 ...
2 votes
1 answer
339 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. ...
0 votes
2 answers
2k views

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. ...
2 votes
3 answers
1k views

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 ...
3 votes
1 answer
268 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 (...
3 votes
1 answer
2k views

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 ...
1 vote
2 answers
428 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 ...