I am trying to make a helper with QTextBrowser. As I understood, home(), backward() and forward() are already implemented in QTextBrowser and required only connections to the buttons. Below there is .h and .cpp files
#ifndef HELPWINDOW_H
#define HELPWINDOW_H
#include <QDialog>
namespace Ui {
class HelpWindow;
}
class HelpWindow : public QDialog
{
Q_OBJECT
public:
explicit HelpWindow(QWidget *parent = 0);
~HelpWindow();
private slots:
private:
Ui::HelpWindow *ui;
};
#endif // HELPWINDOW_H
and
#include "helpwindow.h"
#include "ui_helpwindow.h"
HelpWindow::HelpWindow(QWidget *parent) :
QDialog(parent),
ui(new Ui::HelpWindow)
{
ui->setupUi(this);
// connection
connect(ui->pushButton_home,SIGNAL(clicked()),ui->textBrowser,SLOT(home()));
connect(ui->pushButton_forward,SIGNAL(clicked()),ui->textBrowser,SLOT(forward()));
connect(ui->pushButton_backward,SIGNAL(clicked()),ui->textBrowser,SLOT(backward()));
}
HelpWindow::~HelpWindow()
{
delete ui;
}
There is no any error message. It is possible to read and click the links inside QTextBrowser. Only there are no any actions with buttons. What do I miss here?
You need to call either one or both of the following properties
ui->textBrowser.setOpenLinks(true);
ui->textBrowser.setOpenExternalLinks(true);
and if you want filter or re-route the links at runtime
connect(ui->textBrowser, SIGNAL(sourceChanged(QUrl)), pointerToYourCode, SLOT(slotSourceChanged(QUrl)));
and implement
void YourCode::slotSourceChanged(const QUrl& url) {...}
I found why it did not work. The initial source should be specify:
ui->textBrowser->setSource(QUrl::fromLocalFile("help/index.html"));
Thank you, Jens for spending time.
Related
I'm trying to connect signals from a child window (QDialog named VolumePage) to its parent (QMainWindow named MockUI). I'm running into a:
invalid use of incomplete type 'class Ui::VolumePage'
error when I attempt to make the connection.
I'm trying to connect inside the MockUI.cpp when I make the volume page. (Happens on a button press)
void MockUI::on_pushButton_3_clicked()
{
//Non-Modal Approach
volPage = new VolumePage(this);
volPage->show();
connect(volPage->ui->verticalSlider,SIGNAL(valueChanged(int)),ui->progressBar,SLOT(setValue(int)));
}
I've made Ui::VolumePage *ui; public.
Here's the entire error:
error: invalid use of incomplete type 'class Ui::VolumePage'
connect(volPage->ui->verticalSlider,SIGNAL(valueChanged(int)),ui->progressBar,SLOT(setValue(int)));
Can anyone help me understand what the problem is, or another clean way to do what I'm trying to do?
Edit: (Additional Source)
VolumePage.h:
#ifndef VOLUMEPAGE_H
#define VOLUMEPAGE_H
#include <QDialog>
namespace Ui {
class VolumePage;
}
class VolumePage : public QDialog
{
Q_OBJECT
public:
explicit VolumePage(QWidget *parent = 0);
Ui::VolumePage *ui;
~VolumePage();
private slots:
void on_verticalSlider_valueChanged(int value);
private:
};
#endif // VOLUMEPAGE_H
mockUI.cpp:
#include "mockUI.h"
#include "ui_mock_ics.h"
#include <QLCDNumber>
#include "volumepage.h"
MockUI::MockUI(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MockUI)
{
ui->setupUi(this);
}
MockUI::~MockUI()
{
delete ui;
}
void MockUI::on_pushButton_3_clicked()
{
//Modal Approach
//VolumePage volPage;
//volPage.setModal(true);
//volPage.exec();
//Non-Modal Approach
volPage = new VolumePage(this);
volPage->show();
connect(volPage->ui->verticalSlider,SIGNAL(valueChanged(int)),ui->progressBar,SLOT(setValue(int)));
}
volumepage.cpp:
#include "volumepage.h"
#include "mockUI.h"
#include "ui_volumepage.h"
VolumePage::VolumePage(QWidget *parent) :
QDialog(parent),
ui(new Ui::VolumePage)
{
ui->setupUi(this);
setWindowFlags(Qt::FramelessWindowHint | Qt::Popup);
//Mock_ICS* ics = (Mock_ICS*)parent;
//connect(ui->verticalSlider,SIGNAL(valueChanged(int)),ics->ui->progressBar,SLOT(setValue(int)));
//connect(ui->verticalSlider,SIGNAL(valueChanged(int)),this->parent()->progressBar,SLOT(setValue(int)));
}
VolumePage::~VolumePage()
{
delete ui;
}
Ui::VolumePage *ui should remain private. Instead create a signal on the volPage, something like verticalSliderValueChanged(int value). See below...
mockui.h
#ifndef MOCKUI_H
#define MOCKUI_H
#include <QMainWindow>
#include "volumepage.h"
namespace Ui {
class MockUI;
}
class MockUI : public QMainWindow
{
Q_OBJECT
public:
explicit MockUI(QWidget *parent = 0);
~MockUI();
VolumePage* volPage;
private slots:
void on_pushButton_3_clicked();
private:
Ui::MockUI *ui;
};
#endif // MOCKUI_H
mockui.cpp
#include "mockui.h"
#include "ui_mockui.h"
#include "volumepage.h"
MockUI::MockUI(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MockUI)
{
ui->setupUi(this);
}
MockUI::~MockUI()
{
delete ui;
}
void MockUI::on_pushButton_3_clicked()
{
//Non-Modal Approach
volPage = new VolumePage(this);
volPage->show();
connect(volPage,SIGNAL(verticalSliderValueChanged(int)),ui->progressBar,SLOT(setValue(int)));
}
volumepage.h
#ifndef VOLUMEPAGE_H
#define VOLUMEPAGE_H
#include <QDialog>
namespace Ui {
class VolumePage;
}
class VolumePage : public QDialog
{
Q_OBJECT
public:
explicit VolumePage(QWidget *parent = 0);
~VolumePage();
signals:
void verticalSliderValueChanged(int value);
private slots:
void on_verticalSlider_valueChanged(int value);
private:
Ui::VolumePage *ui;
};
#endif // VOLUMEPAGE_H
volumepage.cpp
#include "volumepage.h"
#include "ui_volumepage.h"
VolumePage::VolumePage(QWidget *parent) :
QDialog(parent),
ui(new Ui::VolumePage)
{
ui->setupUi(this);
}
VolumePage::~VolumePage()
{
delete ui;
}
void VolumePage::on_verticalSlider_valueChanged(int value)
{
emit verticalSliderValueChanged(value);
}
This is an example of the pImpl idiom in C++. Class VolumePage is the one you should be using - this is the "public" interface of what Qt Creator has generated. Ui::VolumePage contains the complicated details you should not worry about.
So, in your code you should be using VolumePage, not Ui::VolumePage. You shouldn't have make Ui::VolumePage public.
I want to display a "generating image..." kind of modal dialog, other than the main GUI. This "generating image..." dialog should be temporary, and be displayed and disappear without user intervention.
For displaying this dialog, the Qt code should check for existence of a .txt file in a specific location in the PC's hard disk. If the .txt file exists, then the dialog should pop-up.
For making this dialog disappear, the Qt code should check whether that .txt file contains the string "OK" in the first line. The dialog should disappear only when this "OK" is found, until then it should continue to display "generating image..."
A good way to do this is to use signal slot mechanism. I would like to know, what functions should be used as SIGNALS in both the cases, of displaying and removing the dialog.
So far, I could manage a simple code, illustrating a "generating image..." using signal slot mechanism, but with setValue() and pressing a push button(i.e. involving user intervention), and not with the checking of .txt file or the "OK" string inside that .txt file(user non-intervention).
Please advise me, whether my logic can be implemented? If yes, how? Also, what SIGNALs should be used?
************************UPDATED SECTION(as of Feb 24th '14):****************************************************
I have revised the code according to Dmitry Sazonov's suggestions. I am able to display the loading GIF whenever a new file is created/deleted in a designated directory. Now I want to close this loading qDialog, when the usbResponse.txt file has "ok" inside it. I tried using signal slot, to implement hide(), but could not get it.
I do not get errors, but the qDialog window does not close as expected. I tried both, secDialog.close() and secDialog.hide(), but the window didn't close. Perhaps because the secDialog object is not the same in both the SLOTs. So I also made secDialog, a global object, but I received an error as follows:-
QWidget: Must construct a QApplication before a QWidget
I looked it up: https://qt-project.org/forums/viewthread/12838
Changed the build modes, accordingly, but that didn't help either. Please tell me how do I close my qDialogs, when I find the "ok" in usbResponse.txt file.
************************UPDATED SECTION(as of Mar 14th '14):****************************************************
I could close the qDialog containing the GIF using hide(). I have done a total overhaul of the code. As mentioned above, the qDialog containing the GIF should appear whenever a text file called usbResponse.txt exists at a designated location. Also taking #Dmitry Sazonov's advice, I am able to close the GIF whenever that txt file i.e. usbResponse.txt is modified, using FileSystemWatcher.
I'm continuously scanning for the existence of the .txt using threads. When I find the file, I display the loading GIF. When the .txt is modified the GIF should disappear. This works fine for the first iteration, i.e. when
(the following are observations after debugging)
the usbResponse.txt exists => GIF is displayed
when usbResponse.txt is modified => GIF is hidden & the .txt is deleted.
THe problem, in next iteraiton,(i.e. all iterations after the first)
the usbResponse.txt is created => the GIF is displayed.
when usbResponse.txt is modified, the debug pointer continues to remain in
afterFileHasBeenFound()
whereas it should have gone in
closeModified(const QString &str)
What is my mistake here?
Here is my code:
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QFile>
#include <QDebug>
#include <QFileSystemWatcher>
#include "dialog.h"
#include "mythread.h"
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
public slots:
void afterFileHasBeenFound();
void closeModified(const QString &str);
private slots:
private:
Ui::MainWindow *ui;
Dialog *pDialog;
MyThread *mThread;
};
#endif // MAINWINDOW_H
dialog.h
#ifndef DIALOG_H
#define DIALOG_H
#include <QDialog>
#include <QMovie>
#include <QLabel>
#define GIF_PATH "E:\\QT1\\timeStampPopUp\\timeStampPopUp\\loading.gif"
namespace Ui {
class Dialog;
}
class Dialog : public QDialog
{
Q_OBJECT
public:
explicit Dialog(QWidget *parent = 0);
~Dialog();
void displayLoadingGif();
private:
Ui::Dialog *ui;
};
#endif // DIALOG_H
mythread.h
#ifndef MYTHREAD_H
#define MYTHREAD_H
#include <QThread>
#include <QtCore>
#include <QDebug>
#define FILE_PATH "E:\\QT1\\dialogClose2\\dialogClose2\\usbResponse.txt"
class MyThread : public QThread
{
Q_OBJECT
public:
explicit MyThread(QObject *parent = 0);
void run();
QString name;
int exec();
void checkFile();
signals:
void testSignal(QString message);
void fileFoundDisplayGif();
public slots:
};
#endif // MYTHREAD_H
dialog.cpp
#include "dialog.h"
#include "ui_dialog.h"
Dialog::Dialog(QWidget *parent) :
QDialog(parent),
ui(new Ui::Dialog)
{
ui->setupUi(this);
displayLoadingGif();
}
Dialog::~Dialog()
{
delete ui;
}
void Dialog::displayLoadingGif()
{
QMovie *pMovie = new QMovie(GIF_PATH);
ui->loadingGifLabel->setMovie(pMovie);
pMovie->start();
}
mythread.cpp
#include "mythread.h"
MyThread::MyThread(QObject *parent) :
QThread(parent)
{
}
void MyThread::run()
{
exec();
}
int MyThread::exec()
{
while(1)
{
checkFile();
emit(testSignal("hello world!!"));
sleep(1);
}
}
void MyThread::checkFile()
{
QFile file(FILE_PATH);
if(file.exists())
{
qDebug()<<"exists";
emit(fileFoundDisplayGif());
}
else
qDebug()<<"doesn't exist";
}
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
mThread = new MyThread(this);
mThread->name = "mThread";
connect(mThread, SIGNAL(fileFoundDisplayGif()), this, SLOT(afterFileHasBeenFound()), Qt::QueuedConnection);
mThread->start();
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::afterFileHasBeenFound()
{
if(pDialog != NULL)
return;
pDialog = new Dialog();
pDialog->setModal(true);
pDialog->show();
}
void MainWindow::closeModified(const QString &str)
{
Q_UNUSED(str)
if(pDialog != NULL)
{
pDialog->hide();
}
QFile file(FILE_PATH);
file.remove();
pDialog = NULL;
}
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
QFileSystemWatcher fileWatcher;
fileWatcher.addPath(FILE_PATH);
QStringList fileList = fileWatcher.files();
Q_FOREACH(QString file, fileList)
qDebug() << "File name " << file;
MainWindow* mc = new MainWindow;
QObject::connect(&fileWatcher, SIGNAL(fileChanged(QString)), mc, SLOT(closeModified(QString)));
mc->show();
return a.exec();
}
Do not use timers for checking file. Use QFileSystemWatcher for traking file modifications.
Implement a slot that will check file content on modification. And call hide() method, when your "OK" text appeared.
IMHO: your solution is to messy. There are a lot of other syncronization mechanisms between processed. Can you modify code of tool that generates image? Should it really work as another process?
Is it possible to use a templated class (not based on QObject and doesn't have Q_OBJECT macro) in Qt? I keep getting a linker error when trying to use a templated class. however, when I remove the template from the class, it compiles and links fine. I'm just trying to declare a local variable of type Filter, which uses a template, and I get this linker error:
error: undefined reference to `NumericFilter<int>::NumericFilter(int, int)'
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "filter.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
NumericFilter<int> filter(0, 1);
}
MainWindow::~MainWindow()
{
delete ui;
}
filter.h
template <class T>
class NumericFilter {
public:
NumericFilter (int itemType, int val);
protected:
T m_val;
};
filter.cpp
#include "filter.h"
template <class T>
NumericFilter<T>::NumericFilter (int, int)
{
}
Note that if you remove the template in the declaration and source files and comment out the 'T' member, then it compiles fine.
http://www.parashift.com/c++-faq-lite/separate-template-fn-defn-from-decl.html
If you compile and (try to) link these two .cpp files, most compilers will generate linker errors. There are two solutions for this. The first solution is to physically move the definition of the template function into the .h file, even if it is not an inline function.
This solution may (or may not!) cause significant code bloat, meaning your executable size may increase dramatically (or, if your compiler is smart enough, may not; try it and see).
The other solution is to leave the definition of the template function in the .cpp file and simply add the line template void foo(); to that file:
// File "foo.cpp"
#include <iostream>
#include "foo.h"
template<typename T> void foo()
{
std::cout << "Here I am!\n";
}
template void foo<int>();
So for your case, you would have in your .cpp file:
#include "filter.h"
template <class T>
NumericFilter<T>::NumericFilter(int, int)
{
}
template NumericFilter<int>::NumericFilter<int>(int, int); // added line!!!
Tada! No compile errors!
BTW, parashift's explanations on templates in C++ are the best IMHO.
Hope that helps.
I am implementing a card game. I want the window ui to be an object of class Rule, so that Rule can modify the GUI directly.
So Rule has an object Window * ui initialized in the constructor.
But during compilation, the compiler tells me that in rule.h, "Window has not been declared", "Window is not a type". I included <window.h>, everything has the same type, everything is initialized, so I run out of ideas of why it does not work.
EDIT: I edited the code following alexisdm's notes. In addition, in rule.h, I had to change the definition of ui from Window * ui to Ui::Window *ui, because in window.h, ui is defined as Ui::Window * ui, and this is the object I want Rule::rule to control.
But now, in rule.cpp, ui->do_stuff() does not compile, because Ui::Window does not have the do_stuff() function, but Window does...
Arg! What to do?!! ui->do_stuff() works fine in window.cpp. Inheritance problem?
window.cpp:
Window::Window(QWidget *parent) :
QDialog(parent),
ui(new Ui::Window)
{
ui->setupUi(this);
player = new Game_state(); /* Game state */
rule = new Rule(player, ui); /* Implement the action of cards*/
}
void Window::do_stuff(){
//Do stuff
}
window.h
#include <QDialog>
#include "game_state.h"
#include "rule.h"
class Rule;
namespace Ui {
class Window;
}
class Window : public QDialog
{
Q_OBJECT
public:
explicit Window(QWidget *parent = 0);
~Window();
Game_state * player;
Rule * rule;
void do_stuff();
private:
Ui::Window *ui;
};
rule.h
#ifndef RULE_H
#define RULE_H
#include "window.h"
#include <game_state.h>
class Window;
class Rule{
public:
Rule(Game_state *, Ui::Window *);
void action(Card *);
private:
Game_state * player;
Ui::Window * ui;
};
#endif // RULE_H
rule.cpp
#include <rule.h>
Rule::Rule(Game_state * game, Ui::Window * window){
player = game;
ui = window;
}
void Rule::stuff(){
ui->do_stuff();
}
There is a circular dependency in your headers: window.h and rule.h are referencing each other.
You should replace both #include by forward declarations to avoid it.
class Window; // instead of #include "window.h"
class Rule; // instead of #include "rule.h"
You'll still need to add #include "window.h" in rule.cpp, and #include "rule.h" in window.cpp.
My guess is the name of your class, Window, is too generic and #include <window.h> probably includes the system one instead of yours.
Try change the clase and header name to something more specific to your app like CardWindow, or use #include "window.h"
I've been using this example to create a http request for my Qt Nokia application, but I can't seem to get it working.
At first I Tried QHttp, but it is deprecated.
Here's the structure:
mainwindow.cpp
mainwindow.h
request.cpp
request.h
Here's the code:
mainwindow.cpp
MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
{
ui->setupUi(this);
Request* request = new Request();
}
MainWindow::~MainWindow()
{
delete ui;
}
Request.h
#ifndef REQUEST_H
#define REQUEST_H
#include <QNetworkAccessManager>
#include <QUrl>
#include <QNetworkReply>
#include <QNetworkRequest>
class Request : QObject
{
//Q_OBJECT
public:
Request();
public slots:
void finishedSlot(QNetworkReply* reply);
void checkConnection(QNetworkReply* reply);
};
#endif // REQUEST_H
And btw... what use is the "Q_OBJECT" for?
Request.cpp
#include "request.h"
#include <QDebug>
#include <QMessageBox>
Request::Request()
{
QNetworkAccessManager* oNetworkAccessManager = new QNetworkAccessManager(this);
QObject::connect(oNetworkAccessManager, SIGNAL(finished(QNetworkReply*)),this,SLOT(finishedSlot(QNetworkReply*)));
QObject::connect(oNetworkAccessManager, SIGNAL(networkSessionConnected()),this,SLOT(checkConnection(QNetworkReply*)));
QUrl url("http://www.redrock.no");
QNetworkReply* reply = oNetworkAccessManager->get(QNetworkRequest(url));
}
void Request::checkConnection(QNetworkReply* reply)
{
QMessageBox msgBox;
msgBox.setText("checkConnection");
msgBox.setInformativeText("The network session has started");
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
msgBox.setDefaultButton(QMessageBox::Save);
int ret = msgBox.exec();
}
void Request::finishedSlot(QNetworkReply* reply)
{
QMessageBox msgBox;
msgBox.setText("checkConnection");
msgBox.setInformativeText("The request is done");
msgBox.setStandardButtons(QMessageBox::Save | QMessageBox::Discard | QMessageBox::Cancel);
msgBox.setDefaultButton(QMessageBox::Save);
int ret = msgBox.exec();
}
The message boxes is just since I don't have a usb cable for my phone.
I have set breakpoints at both the "checkConnection" slot and the "finishedSlot" slot, but nothing happens there.
Anyone got an idea of what I could be doing wrong?
Here is an explanation of the Q_OBJECT macro:
http://doc.qt.nokia.com/latest/qobject.html#Q_OBJECT
Among other things,
The Q_OBJECT macro must appear in the
private section of a class definition
that declares its own signals and
slots...
So I would first try uncommenting that and see what changes. It should at least get your signals and slots talking to one another. (This is a Qt-specific feature, not part of C++, and needs the Q_OBJECT macro.) I didn't look carefully at the rest of your code, because that is the obvious first thing to try. Actually, I am surprised that it would even compile without that.
ok, finally i found what's wrong... and as usual, it's just a minor error from me.
I uncommented the Q_OBJECT, and got some vtable error or something like that. I did get this error message earlier today when i had the Q_OBJECT there, and that is why i commenting it.
But since i'm new to Qt i hade forgot to incelude the QObject in the request.h
"#include "
And that fixed everything for me :)
Thanks for the explenation and elaboration Dave.