I am new to c++ and even newer to Qt on Linux.
Can any one give me a general idea of how to display text in a textbrowser in Qt? I can't post my code because of the seative nature of the project I am working on. All I need is a basic understanding of how to do this related to slots and signals.
My application is this: I am taking input from a CSV file, counting the ords and then displaying the number of counted words along with the line of text in an output window.
It works fine in console c++ program. However, when I code it in Qt, it does not work.
Any advise or help would be welcome.
sorry for the bad question I asked earlier.
It turns out it was a configuration issue on my part.
Related
I have an application that has some sort of log viewer, that needs to be able to render formatted log records that are inserted to it in real time.
I am writing this in Qt and so far I was using QTextEdit for rendering of the text, which was beautified using some html tags and later inserted either with setHtml or insertHtml.
The problem is however, that these functions are insanely CPU intensive and run for ages, hanging whole application.
A similar question was asked here: QTextEdit.insertHtml() is very slow
Apart it has no really useful answer, other than stating it's really slow, it actually asks a different thing. I don't need to speed up setHtml or insertHtml. I am willing to use entirely different technique if possible.
Is there any mechanism within Qt that would allow for really fast insertions of text? Or maybe even completely different component than QTextEdit?
Is there any way to append new line to QTextEdit which contains rich text (generated in any way) that is really fast?
I also noticed QTextBrowser but it seems to be just an extension of TextEdit, could it be faster?
You should give QPlainTextEdit a try. It uses the same technology as QTextEdit but is a lot faster. It is optimized for plain text handling but do not let that fool you, it still has some basic support for formatting using HTML. You can append HTML formatted text with appendHtml().
In my application, I also need to display a large log of the task, approximately 3500 lines. Some lines of the log should be colored. For this, I used HTML formatting. QTextEdit.setHtml with this amount of text, freezed my GUI.
I replaced QTextEdit with QListWidget, in which QListWidgetItem is created for each line of the log.
It began to work much faster, without friezes.
And I saved colored text, just simple by using the QListWidgetItem.setForeground.
[This post][1]
[1]: Performantly appending (rich) text to QTextEdit or QTextBrowser in Qt contains an answer to this problem. The gist: instead of simply appending an HTML snippet, manipulate the underlying document directly.
However, I suggest that if your display really is a list of single lines, you create a QAbstractListModel QAbstractTableModel derived class instead and show it in an item view.
I totally have no idea. Any suggestion on it? It is a command window accepting some commands like:
> Add(1, 2)
and other similars.
This is a very vague question. Since there is no built-in parser generation in Qt, you can combine boost or YACC to get parsing. Use a QInputDialog or a QTextEdit from Qt for input and display. Basically set up some events in Qt for the parsing.
Have a class extending QInputDialog storing a string cmd. This class has a parsing function which will call the right code from the entered command or report an error. Then store a set of completed commands or outputs which you display back to the user. For exact code, you need to try something, and look at some tutorials, and ask more SO questions :)
Hope this is an ok start to get your mind going.
I want to make a GUI . I have a code that runs, made in C++. The project is made in Visual Studio(Visual C++ 2010 Express).
The outputs now are printed in command line. I want to tranform this to be printed to a window.
Is there a way to do this in this already made project ? Or I have to make a new one.
P.S. The code is consists of many, about 20 .cpp files and about 5 .h headers.
Following my comment on your original post here's some more information that will help you get through this:
Simply turn your "cout << ...." calls (or printf if the code is
actually C) to append the text to the UI control you want the output
to be displayed in? Or you can check this "hack" out:
cplusplus.com/forum/general/27876
Now simply add a new source file to the project: call it.. MyProjectGUI.cpp
Follow this guide here to setup the window on your project:
http://msdn.microsoft.com/en-us/library/bb384843.aspx
Then go through the rest of your code (or use the hack mentioned above or some kind of pipe to redirect your output (probably a lot! more complicated than the following method) and simply replace your cout << / printf calls with something like what's detailed in here: http://www.programmersheaven.com/mb/windows/105327/105327/appending-text-to-edit-control/
You'll find the basic idea of your modifications to be along these lines:
Create a simple window
Add a new edit field to the window (http://en.wikibooks.org/wiki/Windows_Programming/User_Interface_Controls and http://msdn.microsoft.com/en-us/library/windows/desktop/ms632680(v=vs.85).aspx)
Replace all console printing calls with a call to your append function for the edit box in the GUI
Best of luck with this (I might write up some code if I'm bothered but don't count on it -> no time. You should be able to figure it out with what I've posted though)
You dont have to do another project. It is enough to include headers and add libraries to linker. You should try a QT which is portable, well written and easy to learn. My one advice is to stay as portable as possible, in example you can create a makefile for your project so add new libraries will be a quiet easy job and not related to IDE . Dont stick to one environment.
I am writing a simple program in C++ to be run in a terminal window. I would like the output text to be locked in position on the screen. Instead of each new line appearing at the bottom of the screen and pushing everything up, I would like to be able to change a line of text or some characters in a line of text, while keeping other lines above and below it static. I know I have seen this done in terminal, and I believe it was done with C++, but I can't find any documentation on it. I cannot even think of what this type of display might be called. My google fu has failed me; please help. If you can tell me what commands/library to use, that would be great, but even being able to tell me what commands accomplish this in a programming language other than C++ would give me more to go on than I have now.
You want ncurses, a library for displaying text on a terminal.
If you are programming for Microsoft Windows, try googling for Win32 Console Functions.
I am working with QT Creator. I have a form that contains a push button and an Line Edit. I would like to print a string that i give programatically in this LineEdit.Secondly I would also like to the from the LineBox a string that I fill in and print it using QMessageBox.
How to do it? Need some help. I don't know how to access the displayText() to write and read from a LineEdit.
I would like to specify that I put the push button and the lineedit on the Form using drag and drop.
I am working in c++ under Ubuntu
Appreciate.
You use QLineEdit::setText() to change the text and QLineEdit::text() to read.
Your questions are very basic and show a clear lack of studying the documentation and experimenting thing yourself. Qt is one of the better documented frameworks out there and with lots of examples. Please take your time to go through them.