Please help with actual C++ code

[Anonymous_Banned275]

I am, honestly trying hard to learn C++, but RTFM does not help i n this case.

The first line of code complies ans adds new sub menu with text.
Not really understand how , but that is irrelevant.

The second line won't compile and I get ton of error messages, none of them suggest the correct syntax to add check box to the menu.

I really tried to read the errors to find the correct syntax, but no luck.
So I am asking for correction to my code.

Maybe later I will post the errors and let somebody explain to me how to read them to find correct syntax.

    QAction tempAction;
                    subMenu[index]->addAction(" test ");
                    subMenu[index]->addAction(tempAction.setCheckable(true));

Here are is my current , basic error messages

/mnt/A_BT_DEC10/BT__PROGRAMS/A_JAN11/A_BT_LIBRARY/terminal_Bluetooth/mainwindow_Bluetooth.cpp:3590: error: no matching member function for call to 'addAction'
mainwindow_Bluetooth.cpp:3590:37: error: no matching member function for call to 'addAction'
                    subMenu[index]->addAction(tempAction.setCheckable(true));
                    ~~~~~~~~~~~~~~~~^~~~~~~~~
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qwidget.h:559:10: note: candidate function not viable: cannot convert argument of incomplete type 'void' to 'QAction *' for 1st argument
    void addAction(QAction *action);
         ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:79:14: note: candidate function not viable: cannot convert argument of incomplete type 'void' to 'const QString' for 1st argument
    QAction *addAction(const QString &text);
             ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:80:14: note: candidate function not viable: requires 2 arguments, but 1 was provided
    QAction *addAction(const QIcon &icon, const QString &text);
             ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:111:21: note: candidate function template not viable: requires at least 2 arguments, but 1 was provided
    inline QAction *addAction(const QString &text, Func1 slot, const QKeySequence &shortcut = 0)
                    ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:81:14: note: candidate function not viable: requires at least 3 arguments, but 1 was provided
    QAction *addAction(const QString &text, const QObject *receiver, const char* member, const QKeySequence &shortcut = 0);
             ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:98:9: note: candidate function template not viable: requires at least 3 arguments, but 1 was provided
        addAction(const QString &text, const Obj *object, Func1 slot, const QKeySequence &shortcut = 0)
        ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:139:21: note: candidate function template not viable: requires at least 3 arguments, but 1 was provided
    inline QAction *addAction(const QIcon &actionIcon, const QString &text, Func1 slot, const QKeySequence &shortcut = 0)
                    ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:82:14: note: candidate function not viable: requires at least 4 arguments, but 1 was provided
    QAction *addAction(const QIcon &icon, const QString &text, const QObject *receiver, const char* member, const QKeySequence &shortcut = 0);
             ^
/home/nov25-1/Qt/5.15.2/gcc_64/include/QtWidgets/qmenu.h:126:9: note: candidate function template not viable: requires at least 4 arguments, but 1 was provided
        addAction(const QIcon &actionIcon, const QString &text, const Obj *object, Func1 slot, const QKeySequence &shortcut = 0)
        ^

[JonB]

@AnneRanch
As per the first line, addAction(" test "), you can call addAction() with a string. Or you can call it with a QAction * you have created. But tempAction.setCheckable(true) class a method which returns void, there is no chance of passing this to anything as a parameter.

There are a couple of ways of doing what you want. What about this:

QAction *tempAction = subMenu[index]->addAction(" test ");
tempAction->setCheckable(true);

// or equivalent, does not matter which one you do, above is one line less code
QAction* tempAction = new QAction(" test ", this);
tempAction->setCheckable(true);
subMenu[index]->addAction(tempAction);

[Axel Spoerl]

The error messages list all overrides of QWidget::addAction(), none of which matches the 2nd call to this method. That's where reading the documentation really helps. I disagree with you. RTM is exactly what could have prevented your issue. Drop the F. Bad karma.

The difficulty is now, that one the one hand you want to learn C++ without reading much, on the other hand you don't tell us, what you actually want to do. Add one action and make it checkable? Add two actions? What is the heap allocated tempActionsupposed to be? It'll go out of scope when the function returns - that's a risky ride.

Since you (as usual) won't answer any of those questions, here is some C++ code that is as similar to yours as possible. It will compile, and it won't cause crashes. Maybe it even does what you expect. We will never know, because usually you won't tell.

QAction *tempAction = subMenu[index]->addAction(" test ");
tempAction->setCheckable(true));

[Axel Spoerl]

@JonB
Simple minds think alike. @JonB was not only faster, but also a much better explainer.

[Anonymous_Banned275]

@JonB OK, here is my take on this.
I understand that I am using QMenu method "addAction".
"addAction" takes parameters as any function/ method.
When I pass text the result is - new menu of text gets created. . That is probably explained in doc, but it is weird how text creates new menu.But that is OK and I am using that and it does the job.

Now I want to use QAction method "addCheckable" as a parameter to "addAction". That has no relation to "text"....

So I need to create QAction object.
Am I correct so far ?

[Chris Kawa]

Menus are containers. Actions are elements in that container.

menu->addAction("hello") creates an action with text "hello" and adds it to a menu.
menu->addMenu("hello") creates a new menu, then creates an action that opens this menu with text "hello" and adds that action to the original menu.
menu->menuAction() returns an action that opens this menu.

Maybe this example helps:

QMenu* menu = menuBar->addMenu("Action that opens menu");
QAction* actionThatOpensMenu = menu->menuAction();

QAction* actionInMenu = menu->addAction("Action in menu");

QAction* checkableActionInMenu = menu->addAction("Checkable action in menu");
checkableActionInMenu->setCheckable(true);

QMenu* subMenu = menu->addMenu("Action that opens sub menu");
QAction* actionThatOpensSubMenu = subMenu->menuAction();

QAction* actionInSubMenu = subMenu->addAction("Action in sub menu");

QAction* checkableActionInSubMenu = subMenu->addAction("Checkable action in sub menu");
checkableActionInSubMenu->setCheckable(true);

[Anonymous_Banned275]

@Chris-Kawa Thanks Chris - I am willing to redo my clumsy code...

Give me some time to digest your post.
Yes it has been a struggle to keep QMenu and QAction working with each other.

I did implement last suggestion with mixed result - I get "check box" as a last entry in submenu without any text .

I am posting my current messy code FOR ENTERTAINMENT purpose ONLY.

Let me take a detailed look at the code you posted BEFORE any more suggestions , OK ?

                  QAction* tempAction = new QAction(); //  text , this);
                    tempAction->setCheckable(true);
                    //subMenu[index]->addAction(tempAction);
                    for (index_sub = 0; index_sub < subSize; ++index_sub)
                    { // inner loop
                        { // process block
                            { // add subsub menu
                                text = " index_sub " ;
                                text += QString::number(index_sub);
                                qDebug()<<text;


                                subMenu[index]->addAction(list_array[index][ index_sub] + " #" + QString::number( index_sub));

                                //tempAction->setCheckable(true);
                                subMenu[index]->addAction(tempAction);

.

[Anonymous_Banned275]

@AnneRanch OK, I changed bunch of code and got Chris suggestion working as expected . It adds single entry to main menus , so I need to work on that.

Thanks Chris.

[Anonymous_Banned275]

@AnneRanch

Here is my current , working , main loop code...

               { // // main menu process block
#ifdef ARRAY
                    text = " main menu process block ";
                    qDebug() << text;
#endif
                    // start with action
                    // attach to existing menu
                    new_mainAction[index] = m_ui->menuWindow_cpntrol->menuAction(); // C
                    new_checkableActionInMenu[index] = m_ui->menuWindow_cpntrol->addAction(list[index] + " # " + QString::number(index));
                    
                    
                    new_checkableActionInMenu[index]->setCheckable(true);        // TOK
                    //checkableActionInMenu[index]->setCheckable(false);       // TOK
                    
                } // main menu process block

I cannot help to say - there is a real difference in contributing to solution with few lines of REAL issue description and ....

Unfortunately...

Thanks a million Chris I owe you a beer.
Real Czech Pilsner or ??

[Anonymous_Banned275]

@AnneRanch

I am stuck again
here is the working snippet

               // attach to existing menu
                subMenu_mainAction[index] = m_ui->menuWindow_cpntrol->menuAction(); // C
                subMenu_checkableActionInMenu[index] = m_ui->menuWindow_cpntrol->addAction(list[index] + " # " + QString::number(index));
                subMenu_checkableActionInMenu[index]->setCheckable(true);

                // here need  subMenu  **menu** ?? 

If I understand the workings of adding subMenu ,

I start with the existing "widget " - QMenu .

subMenu_mainAction[index] = m_ui->menuWindow_cpntrol->menuAction();

To add subsubMenu - don't I need the added subMenu menu?

All i have are "actions" and no real subMenu.

[Chris Kawa]

QMenu* menu = menuBar->AddMenu("menu");
QMenu* subMenu = menu->AddMenu("sub menu");
QMenu* subSubMenu = subMenu->AddMenu("sub sub menu");
QMenu* subSubSubMenu = subSubMenu->AddMenu("sub sub sub menu");
QMenu* subSubSubSubMenu = subSubSubMenu->AddMenu("sub sub sub sub menu");
...

Menus all the way down :)

[Anonymous_Banned275]

This post is deleted!

[Anonymous_Banned275]

This post is deleted!

[Chris Kawa]

I would try to help, but I've no idea what you're trying to achieve. Code you posted makes no sense unfortunately.

Maybe you could draw a layout you want and I can help achieve it in code?

[Anonymous_Banned275]

This post is deleted!

[JonB]

@AnneRanch said in Please help with actual C++ code:

I have been told I cannot have "check box : in main menu

You can have a checkbox on an action in any menu, "main" or not. These are created via QMenu::addAction().

However, if you instead add an item which is a submenu (a > that you click on to display a "slide-out" menu) you cannot have a checkbox on that item. These are created via QMenu::addMenu(). And if you think about it, what would be the point of having a checkbox on a menu item which just displays a submenu anyway?

[Anonymous_Banned275]

This post is deleted!

[Anonymous_Banned275]

This post is deleted!

[TomZ]

reading this generally,

@AnneRanch said in Please help with actual C++ code:

The widow just do part of the interface and then I will oopen anither widow to continue... eventually all windows will comlete the required task. So when it is all done I can close it and it would be nice to reopen ALL of then at once when required...hence I thought it could be done in main window...
The whole idea to have uncluttered interaction as required -- one window At the time...

I have the strong suspicion you're trying to implement a GUI idea using existing components which are not actually meant to be used like that at all.
Specifically, QMenu and its related classes are NOT supposed to be used like windows. You're not going to get a good user experience using this kind of windows.

If you share your GUI idea you might get suggestions on how to approach the app.

I suspect a QML component will give you a LOT more flexibility that will allow you to get a good user experience.

[Anonymous_Banned275]

@TomZ Thanks, however... I am just extending "windows
...tile...cascade..." menu using mdiArea (example). I have it essentially working, include "connect". The "problem is " - it can be started with QMenu -that makes submenu extension easy - but adding "checkable " to sub menu is currently failing. Or I can start with QAction then adding depended sub menu fails. Right now I feel starting with "cascading menus " is cleaner ..in case I want to add sususbsub....
The "user" -me - has several depended tasks to accomplish - setup serial connection, then setup dependent Bluetooth connection, configure remote Bluetooth device and then attach it to "serial connection" etc.,key remote device - amateur radio transmitter, listen to "meteor scatter" pings on Internet ...
The basic idea is to do all this in separate forms , I got that going, to keep monitor and me , focused on task...