How may I fix my error prone on_foo_bar slots - qt

Question

I have eight list widgets in a tab widget. They have similar names, and Designer's "Go to slot" mechanism has made links to slots it names (in the "private slots" section of "mainwindow.h") like:
void on_SR0listWidget_itemClicked(QListWidgetItem *item);
I saw warnings that "Slots named on_foo_bar are error-prone," and now I need to change their names in order to discover if that's the cause of the weird behaviour I'm getting.
I tried simply refactoring the names, but that stopped the slot code from working. I used Designer's graphical "Edit Signal/Slot" mechanism and was able to connect a newly added list widget's "itemClicked(QListWidgetItem *item)" signal to a newly added slot, and it looks OK in the graphical representation, but there's no debug message (that I set up in the Slot function) when an item is clicked.
I also use those widgets' "entered" signals, so there will be at least 16 to fix. I would write a script if it could be done by parsing the relevant files.
One example of exactly how to rename one of my replacement slots and connect an "item clicked" or "entered" signal to it (and where it should go) would be a great help.

Answer 1

Signals/slots setup through the designer rely on the names of the widgets involved. This can lead to problems if the widget names are changed. There are times when using the designer method will lead to code that compiles but doesn't actually make the connections you expect. This is why you are getting that warning.
You can get more reliable behavior by connecting the signals and slots programmatically. For example, let's say you have a class header such as:
#include <QMainWindow>
namespace Ui {
class MyWindow;
};
class QListWidgetItem;
class MyWindow : public QMainWindow {
Q_OBJECT
public:
explicit MyWindow(QWidget* parent = nullptr);
~MyWindow() override;
private:
void handleItemClicked(QListWidgetItem* item); // this is your slot
Ui::MyWindow* ui;
};
You can connect the signal/slot together in the cpp file like this:
#include "MyWindow.h"
#include "ui_MyWindow.h"
#include <QDebug>
MyWindow::MyWindow(QWidget* parent)
: QWidget(parent),
ui(new Ui::MyWindow()) {
ui->setupUi(this);
// connect() has many overloads, but in this case we are passing:
// 1. the object emitting the signal
// 2. the signal being emitted
// 3. the object whose slot we want to call
// 4. the slot to connect to
connect(
ui->listWidget, &QListWidget::itemClicked,
this, &MyWindow::handleItemClicked);
}
MyWindow::~MyWindow() {
delete ui;
}
void MyWindow::handleItemClicked(QListWidgetItem* item) {
qDebug() << "item clicked";
}
You can still use the designer to layout your UI - but prefer to manage connections directly in code rather than through the designer.