I cannot force QKeySequence::toString() to return translated shortcut representation despite the fact that it documentation suggests it should work. The docs say: "The strings, "Ctrl", "Shift", etc. are translated using QObject::tr() in the "QShortcut" context." but I am not completely sure what it means by shortcut context. I am probably doing something wrong...
Here is my example. To make it work, I need to copy qtbase_es.qm from Qt installation directory to my project build directory. When the translation is correctly loaded, the action in the menu correctly shows "Action Control+Intro" which is Spanish translation of the shortcut for "Action Ctrl+Enter". But the tooltip on the main window is still "Action (Ctrl+Enter)". I would expect it to be "Action (Control+Intro)", like in the menu. What am I doing wrong?
#include <QAction>
#include <QApplication>
#include <QDebug>
#include <QMainWindow>
#include <QMenuBar>
#include <QTranslator>
int main(int argc, char *argv[])
{
QTranslator spanish;
qDebug() << spanish.load("qtbase_es.qm"); // should return true if correctly loaded
QApplication a(argc, argv);
QApplication::installTranslator(&spanish);
QMainWindow w;
auto menu = new QMenu("Menu");
auto action = menu->addAction("Action");
action->setShortcutContext(Qt::ApplicationShortcut);
action->setShortcut(Qt::CTRL | Qt::Key_Enter);
w.menuBar()->addMenu(menu);
w.show();
QApplication::processEvents(); // I also tried this line but it is useless...
w.setToolTip(QString("%1 (%2)").arg(action->text(), action->shortcut().toString()));
qDebug() << action->shortcut().toString(); // WRONG: returns Ctrl+Enter but I expect Control+Intro
return a.exec();
}
The QShortcut::toString has a SequenceFormat parameter, defaulted to ProtableText. The documentation of the format states, that portable format is intended for e.g. writing to a file.
The native format is intended for displaying to the user, and only this format performs translations.
Try:
qDebug() << action->shortcut().toString(QKeySequence::NativeText);
i have a few questions regarding the gui of cplusplus using Qt creator
well i output an array using a forloop when user's choice is for example "1"
so in qt i created a button for that and i linked it with another window
so when i press on the button it opens another window
now i want to add the output of the forloop into this window
should i include iostream in the new window's .cpp file?
or what should i enter exactly?
in the mainwindow.cpp file here is the code i used to open a new window
void MainWindow::on_pushButton_clicked()
{
movies movies;
movies.setModal(true);
movies.exec();
}
thanks.
You should add a QTextEdit to your window (can be done via Qdesigner). And give this object a name e.g. Textout. Then in the code you should get a pointer to this object through your ui object. And you can use one of many methods to set the text of this object. setText is one option
ui->Textout->setText(Your_output_as_qstring)
Your can use QTextStream to format your text if necessary. Formating can be done with QString as well.
example:
#include <sstream>
#include <QLabel>
#include <QApplication>
int main(int argc, char *argv[])
{
std::stringstream ss;
for (auto s: {"first line", "second line"})
ss << s << std::endl;
QApplication a(argc, argv);
QLabel l;
l.setText(ss.str().c_str());
l.show();
return a.exec();
}
I'm doing some preparation for an exam using Qt framework and I would like to know how to use QInputDialog and QMessageBox in a basic way (my exams are hand written coding)
The Qt API is really confusing to understand when it comes to using and it was fine for my projects because I could accomplish what I wanted in a really "hacky" way a my set book on the subject is very poorly laid out...
Let me get to the point, what would be a clean way of using QInputDialog and QMessageBox in this scenario:
#include <QApplication>
#include <QInputDialog>
#include <QDate>
#include <QMessageBox>
int computeAge(QDate id) {
int years = QDate::currentDate().year() - id.year();
int days = QDate::currentDate().daysTo(QDate
(QDate::currentDate().year(), id.month(), id.day()));
if(days > 0)
years--;
return years
}
int main(int argc, char *argv[]) {
QApplication a(argc, argv);
/* I want my QInputDialog and MessageBox in here somewhere */
return a.exec();
}
For my QInputDialog I want the user to give their birth date (don't worry about input validation)
I want to use the QMessageBox to show the user's age
I just don't understand what parameters need to go into the QInputDialog and QMessageBox in a basic case like because there don't seem to be any examples out there.
How would I accomplish this?
You can do something like:
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
bool ok;
// Ask for birth date as a string.
QString text = QInputDialog::getText(0, "Input dialog",
"Date of Birth:", QLineEdit::Normal,
"", &ok);
if (ok && !text.isEmpty()) {
QDate date = QDate::fromString(text);
int age = computeAge(date);
// Show the age.
QMessageBox::information (0, "The Age",
QString("The age is %1").arg(QString::number(age)));
}
[..]
C++ fltk: I have a window with an in_box and an out_box, how do I make it so that the user can type into the in_box hit enter, then proceed with the rest of the event. Right now the window just shows up and goes away.
Window w(Point(100,100),200,200, "Category Sales");
In_box cat_in(Point(75,75),100,20,"Category:");
Out_box cat_out(Point(75,115),100,20,"Sales:");
w.attach(cat_in);
w.attach(enter);
category = cat_in.get_string();
I'm not sure exactly if this will fix your problem, but to keep the window open, return Fl::run().
I have never seen In_box and Out_box before, so I will assume those are your own classes or structures...
As pointed before - the easiest way to start the FLTK event loop is to use Fl::run() or (FLTK2) fltk::run().
So, here your code should look something like (FLTK2):
#include <fltk/Window.h>
#include <fltk/Widget.h>
#include <fltk/run.h>
using namespace fltk;
int main(int argc, char **argv) {
// your code begins
Window w(Point(100,100),200,200, "Category Sales");
In_box cat_in(Point(75,75),100,20,"Category:");
Out_box cat_out(Point(75,115),100,20,"Sales:");
w.attach(cat_in);
w.attach(enter);
category = cat_in.get_string();
// your code ends
w->end();
w->show(argc, argv);
return run(); // this line is the most important, here we start the FLTK event-loop
}
I have a Qt GUI application running on Windows that allows command-line options to be passed and under some circumstances I want to output a message to the console and then quit, for example:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
if (someCommandLineParam)
{
std::cout << "Hello, world!";
return 0;
}
MainWindow w;
w.show();
return a.exec();
}
However, the console messages do not appear when I run the app from a command-prompt. Does anyone know how I can get this to work?
Windows does not really support dual mode applications.
To see console output you need to create a console application
CONFIG += console
However, if you double click on the program to start the GUI mode version then you will get a console window appearing, which is probably not what you want. To prevent the console window appearing you have to create a GUI mode application in which case you get no output in the console.
One idea may be to create a second small application which is a console application and provides the output. This can call the second one to do the work.
Or you could put all the functionality in a DLL then create two versions of the .exe file which have very simple main functions which call into the DLL. One is for the GUI and one is for the console.
Add:
#ifdef _WIN32
if (AttachConsole(ATTACH_PARENT_PROCESS)) {
freopen("CONOUT$", "w", stdout);
freopen("CONOUT$", "w", stderr);
}
#endif
at the top of main(). This will enable output to the console only if the program is started in a console, and won't pop up a console window in other situations. If you want to create a console window to display messages when you run the app outside a console you can change the condition to:
if (AttachConsole(ATTACH_PARENT_PROCESS) || AllocConsole())
void Console()
{
AllocConsole();
FILE *pFileCon = NULL;
pFileCon = freopen("CONOUT$", "w", stdout);
COORD coordInfo;
coordInfo.X = 130;
coordInfo.Y = 9000;
SetConsoleScreenBufferSize(GetStdHandle(STD_OUTPUT_HANDLE), coordInfo);
SetConsoleMode(GetStdHandle(STD_OUTPUT_HANDLE),ENABLE_QUICK_EDIT_MODE| ENABLE_EXTENDED_FLAGS);
}
int main(int argc, char *argv[])
{
Console();
std::cout<<"start##";
qDebug()<<"start!";
You can't use std::cout as others have said,my way is perfect even for some code can't include "qdebug" !
So many answers to this topic. 0.0
So I tried it with Qt5.x from Win7 to Win10. It took me some hours to have a good working solution which doesn't produce any problems somewhere in the chain:
#include "mainwindow.h"
#include <QApplication>
#include <windows.h>
#include <stdio.h>
#include <iostream>
//
// Add to project file:
// CONFIG += console
//
int main( int argc, char *argv[] )
{
if( argc < 2 )
{
#if defined( Q_OS_WIN )
::ShowWindow( ::GetConsoleWindow(), SW_HIDE ); //hide console window
#endif
QApplication a( argc, argv );
MainWindow *w = new MainWindow;
w->show();
int e = a.exec();
delete w; //needed to execute deconstructor
exit( e ); //needed to exit the hidden console
return e;
}
else
{
QCoreApplication a( argc, argv );
std::string g;
std::cout << "Enter name: ";
std::cin >> g;
std::cout << "Name is: " << g << std::endl;
exit( 0 );
return a.exec();
}
}
I tried it also without the "CONFIG += console", but then you need to redirect the streams and create the console on your own:
#ifdef _WIN32
if (AttachConsole(ATTACH_PARENT_PROCESS) || AllocConsole()){
freopen("CONOUT$", "w", stdout);
freopen("CONOUT$", "w", stderr);
freopen("CONIN$", "r", stdin);
}
#endif
BUT this only works if you start it through a debugger, otherwise all inputs are directed towards the system too. Means, if you type a name via std::cin the system tries to execute the name as a command. (very strange)
Two other warnings to this attempt would be, that you can't use ::FreeConsole() it won't close it and if you start it through a console the app won't close.
Last there is a Qt help section in QApplication to this topic. I tried the example there with an application and it doesn't work for the GUI, it stucked somewhere in an endless loop and the GUI won't be rendered or it simply crashes:
QCoreApplication* createApplication(int &argc, char *argv[])
{
for (int i = 1; i < argc; ++i)
if (!qstrcmp(argv[i], "-no-gui"))
return new QCoreApplication(argc, argv);
return new QApplication(argc, argv);
}
int main(int argc, char* argv[])
{
QScopedPointer<QCoreApplication> app(createApplication(argc, argv));
if (qobject_cast<QApplication *>(app.data())) {
// start GUI version...
} else {
// start non-GUI version...
}
return app->exec();
}
So if you are using Windows and Qt simply use the console option, hide the console if you need the GUI and close it via exit.
No way to output a message to console when using QT += gui.
fprintf(stderr, ...) also can't print output.
Use QMessageBox instead to show the message.
Oh you can Output a message when using QT += gui and CONFIG += console.
You need printf("foo bar") but cout << "foo bar" doesn't works
Something you may want to investigate, at least for windows, is the AllocConsole() function in the windows api. It calls GetStdHandle a few times to redirect stdout, stderr, etc. (A quick test shows this doesn't entirely do what we want it to do. You do get a console window opened alongside your other Qt stuff, but you can't output to it. Presumably, because the console window is open, there is some way to access it, get a handle to it, or access and manipulate it somehow. Here's the MSDN documentation for those interested in figuring this out:
AllocConsole():
http://msdn.microsoft.com/en-us/library/windows/desktop/ms681944%28v=vs.85%29.aspx
GetStdHandle(...):
http://msdn.microsoft.com/en-us/library/windows/desktop/ms683231%28v=vs.85%29.aspx
(I'd add this as a comment, but the rules prevent me from doing so...)
I used this header below for my projects. Hope it helps.
#ifndef __DEBUG__H
#define __DEBUG__H
#include <QtGui>
static void myMessageOutput(bool debug, QtMsgType type, const QString & msg) {
if (!debug) return;
QDateTime dateTime = QDateTime::currentDateTime();
QString dateString = dateTime.toString("yyyy.MM.dd hh:mm:ss:zzz");
switch (type) {
case QtDebugMsg:
fprintf(stderr, "Debug: %s\n", msg.toAscii().data());
break;
case QtWarningMsg:
fprintf(stderr, "Warning: %s\n", msg.toAscii().data());
break;
case QtCriticalMsg:
fprintf(stderr, "Critical: %s\n", msg.toAscii().data());
break;
case QtFatalMsg:
fprintf(stderr, "Fatal: %s\n", msg.toAscii().data());
abort();
}
}
#endif
PS: you could add dateString to output if you want in future.
First of all, why would you need to output to console in a release mode build? Nobody will think to look there when there's a gui...
Second, qDebug is fancy :)
Third, you can try adding console to your .pro's CONFIG, it might work.
In your .pro add
CONFIG += console
It may have been an oversight of other answers, or perhaps it is a requirement of the user to indeed need console output, but the obvious answer to me is to create a secondary window that can be shown or hidden (with a checkbox or button) that shows all messages by appending lines of text to a text box widget and use that as a console?
The benefits of such a solution are:
A simple solution (providing all it displays is a simple log).
The ability to dock the 'console' widget onto the main application window. (In Qt, anyhow).
The ability to create many consoles (if more than 1 thread, etc).
A pretty easy change from local console output to sending log over network to a client.
Hope this gives you food for thought, although I am not in any way yet qualified to postulate on how you should do this, I can imagine it is something very achievable by any one of us with a little searching / reading!
Make sure Qt5Core.dll is in the same directory with your application executable.
I had a similar issue in Qt5 with a console application:
if I start the application from Qt Creator, the output text is visible,
if I open cmd.exe and start the same application there, no output is visible.
Very strange!
I solved it by copying Qt5Core.dll to the directory with the application executable.
Here is my tiny console application:
#include <QCoreApplication>
#include <QDebug>
int main(int argc, char *argv[])
{
int x=343;
QString str("Hello World");
qDebug()<< str << x<<"lalalaa";
QTextStream out(stdout);
out << "aldfjals alsdfajs...";
}
I also played with this, discovering that redirecting output worked, but I never saw output to the console window, which is present for every windows application. This is my solution so far, until I find a Qt replacement for ShowWindow and GetConsoleWindow.
Run this from a command prompt without parameters - get the window. Run from command prompt with parameters (eg. cmd aaa bbb ccc) - you get the text output on the command prompt window - just as you would expect for any Windows console app.
Please excuse the lame example - it represents about 30 minutes of tinkering.
#include "mainwindow.h"
#include <QTextStream>
#include <QCoreApplication>
#include <QApplication>
#include <QWidget>
#include <windows.h>
QT_USE_NAMESPACE
int main(int argc, char *argv[])
{
if (argc > 1) {
// User has specified command-line arguments
QCoreApplication a(argc, argv);
QTextStream out(stdout);
int i;
ShowWindow (GetConsoleWindow(),SW_NORMAL);
for (i=1; i<argc; i++)
out << i << ':' << argv [i] << endl;
out << endl << "Hello, World" << endl;
out << "Application Directory Path:" << a.applicationDirPath() << endl;
out << "Application File Path:" << a.applicationFilePath() << endl;
MessageBox (0,(LPCWSTR)"Continue?",(LPCWSTR)"Silly Question",MB_YESNO);
return 0;
} else {
QApplication a(argc, argv);
MainWindow w;
w.setWindowTitle("Simple example");
w.show();
return a.exec();
}
}
After a rather long struggle with exactly the same problem I found that simply
CONFIG += console
really does the trick. It won't work until you explicitly tell QtCreator to execute qmake on the project (right click on project) AND change something inside the source file, then rebuild. Otherwise compilation is skipped and you still won't see the output on the command line.
Now my program works in both GUI and cmd line mode.
One solution is to run powershell and redirect the output to whatever stream you want.
Below is an example of running powershell from cmd.exe and redirecting my_exec.exe output to both the console and an output.txt file:
powershell ".\my_exec.exe | tee output.txt"
An example (from cmd.exe) which holds open stdout/stderr and doesn't require tee or a temporary file:
my_exec.exe > NUL 2>&1
Easy
Step1: Create new project. Go File->New File or Project --> Other Project -->Empty Project
Step2: Use the below code.
In .pro file
QT +=widgets
CONFIG += console
TARGET = minimal
SOURCES += \ main.cpp
Step3: Create main.cpp and copy the below code.
#include <QApplication>
#include <QtCore>
using namespace std;
QTextStream in(stdin);
QTextStream out(stdout);
int main(int argc, char *argv[]){
QApplication app(argc,argv);
qDebug() << "Please enter some text over here: " << endl;
out.flush();
QString input;
input = in.readLine();
out << "The input is " << input << endl;
return app.exec();
}
I created necessary objects in the code for your understanding.
Just Run It
If you want your program to get multiple inputs with some conditions. Then past the below code in Main.cpp
#include <QApplication>
#include <QtCore>
using namespace std;
QTextStream in(stdin);
QTextStream out(stdout);
int main(int argc, char *argv[]){
QApplication app(argc,argv);
qDebug() << "Please enter some text over here: " << endl;
out.flush();
QString input;
do{
input = in.readLine();
if(input.size()==6){
out << "The input is " << input << endl;
}
else
{
qDebug("Not the exact input man");
}
}while(!input.size()==0);
qDebug(" WE ARE AT THE END");
// endif
return app.exec();
} // end main
Hope it educates you.
Good day,
First of all you can try flushing the buffer
std::cout << "Hello, world!"<<std::endl;
For more Qt based logging you can try using qDebug.