Allocation of incomplete type "Ui::MainWindow"

Aahi

I am getting error in initializing the ui pointer in my MainWindow which I think is automatically generated code. I am Using qt 6. and Here my Code :

MainWindow.cpp

#include "ui_mainwindow.h"
#include "SortFactory.h"
#include "SortObject.h"
#include <QListView>


MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    init();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::init()
{

    ui->comboType->setView(new QListView(this));

    ui->comboType->addItems(SortFactory::getInstance()->getSortList());


    connect(ui->btnSort, &QPushButton::clicked, this, [this]{
        const int type = ui->comboType->currentIndex();
        if (type != ui->canvas->getSortType()) {
            SortObject *obj = SortFactory::getInstance()->createSortObject(type, ui->canvas);
            ui->canvas->setSortObject(type, obj);
        }
        ui->canvas->sort(ui->spinCount->value(), ui->spinInterval->value());
    });


    connect(ui->btnStop, &QPushButton::clicked, this, [this]{
        ui->canvas->stop();
    });

    connect(ui->canvas, &MainCanvas::runFlagChanged,
            this, [this](bool running){
        ui->comboType->setEnabled(!running);
        ui->spinCount->setEnabled(!running);
        ui->spinInterval->setEnabled(!running);
        ui->btnSort->setEnabled(!running);
    });
}

I am getting the main error in the initializer list hence anywhere *ui is used also giving error.

Christian Ehrlicher

Take a look into your generated file "ui_mainwindow.h" and you will see that you do not named your widget "MainWindow" but something else. I would guess "mainwindow".

Aahi

@Christian-Ehrlicher I have mainwindow.h in which I have this MainWindow class here is the code for that.

#define MAINWINDOW_H

#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    void init();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

jsulm

@Aahi Please read again what @Christian-Ehrlicher suggested: "Take a look into your generated file "ui_mainwindow.h" and you will see that you do not named your widget "MainWindow" but something else."

Aahi

@jsulm @Christian-Ehrlicher Thank you so much It is now working I did the following steps in case anyone in the future got the same error.

I checked the ui_mainwindow.h file in that the class in namespace Ui was MainUI so I changed the iterator from Ui::mainwindow" to Ui::MainUI.
I still was getting the error but this time it was "cannot change the iterator from Ui::mainwindow to Ui::MainUI and this was due to the reason that in mainwindow.h the class MainWindow has already declared the variable as Ui::mainwindow *ui so I changed it to Ui::MainUI *ui.
But again got the error No type named "MainUI" in namespace "Ui" and solution was very simple just include ui_mainwindow.h in that and everything is now runnning perfectly fine.

Again thank you so much to @Christian-Ehrlicher and @jsulm

Aahi

@Christian-Ehrlicher @jsulm now the only question is how to mark it as solved?

TheLumbee

@Aahi On your previous answer, click on the three dots to the right and mark it as the correct answer.

TrahdBoy

@Aahi please give a visual representation of your solution, i cant understand your answer.

SGaist

@TrahdBoy hi,

It's all explained here.