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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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4answers
190 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|) ...
0
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2answers
418 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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1answer
89 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 ...
0
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1answer
88 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 ...
11
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2answers
14k 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(...
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1answer
27 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 ...
3
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3answers
218 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 ...
3
votes
3answers
249 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
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0answers
31 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 ...
197
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14answers
257k 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 ...
0
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2answers
122 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
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1answer
127 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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1answer
133 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 ...
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1answer
120 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
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2answers
688 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
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1answer
182 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 ...
5
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3answers
3k 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
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6answers
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 ...
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1answer
153 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 ...
5
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3answers
3k 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 ...
2
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1answer
225 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
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2answers
557 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. ...
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3answers
770 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 ...
10
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2answers
2k 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 ...
2
votes
1answer
103 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 (...
2
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1answer
709 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
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2answers
354 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 ...
0
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2answers
403 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 ...
0
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1answer
103 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 ...
0
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1answer
235 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 ...
3
votes
2answers
805 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/...
0
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1answer
157 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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1answer
895 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 ...
1
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3answers
150 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 ...
1
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1answer
101 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 ...
8
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4answers
7k views

What are some standard design methods to add GUI to a command line app? [closed]

I have an embedded Linux C application that runs with a simple CLI. I am now tasked with creating a GUI that accomplishes the same functionality as the command line program. I am not an accomplished ...
0
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2answers
680 views

Passing by refernce

I am trying to understand the ideas of pointers and references in C++. I am stuck with the following, what would be the specific behaviour in this case? I have a class like this: class MyClass{ ...
6
votes
2answers
2k views

Deploying Qt-based app on Mac OS X

I wrote a cross platform application and I distributed it successfully for Windows and Linux (and tested them on "clean" virtual systems, with no other additional software and/or libraries installed). ...
7
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2answers
407 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 ...
7
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1answer
113 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 ...
0
votes
1answer
139 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 ...
0
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0answers
108 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 ...
2
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2answers
1k 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 ...
0
votes
1answer
142 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 ...
4
votes
1answer
649 views

Qt Quick dynamic QML vs Apple's App Store rules

Imagine that I've got a piece of custom audio hardware that I'd like to be able to control in a multitude of ways via a tablet/touchscreen GUI. In particular, my goals are to have the tablet's ...
4
votes
2answers
1k 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, ...
1
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1answer
1k views

Creating a private in-house application with Qt

I want to create an application using the Qt framework, but can not at all afford a commercial license. While looking at the licensing comparison table, I noticed that the LGPLV3 license said this: ...
2
votes
1answer
2k views

Can Qt desktop programs be recompiled for Android/iOS as-is?

One of the advantages of open-source programs is that they can be ported easily to any platform simply by recompiling. Qt is also a cross-platform toolkit that can work on several platforms simply by ...
32
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1answer
27k views

raw, weak_ptr, unique_ptr, shared_ptr etc… How to choose them wisely?

There is a lot of pointers in C++ but to be honest in 5 years or so in C++ programming (specifically with the Qt Framework) I only use the old raw pointer: SomeKindOfObject *someKindOfObject = new ...
3
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2answers
185 views

Building and Debugging an IDE using the same IDE

This may be a question more suited some Programming Meta Discussions. I was trying to delve deeper into the inner plugin management feature for QT Creator 2.x IDE provided by Digia Inc. So I ...