invalid use of incomplete type ‘class Ui::Task’ Qt with C++

[grafenocarbono]

Hi friends,

I am learning with the book called Mastering Qt5.

I don't understand why the following error appears:

My class Task.h is the following:

#ifndef TASK_H
#define TASK_H

#include <QWidget>
#include <QString>

namespace Ui {
class Task;
}

class Task : public QWidget
{
    Q_OBJECT

public:
    explicit Task(const QString& name, QWidget *parent = 0);
    ~Task();

    void setName(const QString& name);
    QString name() const;
    bool isCompleted() const;

public slots:
    void rename();

signals:
    void removed(Task* task);
    void statusChanged(Task* task);

private slots:
    void checked(bool checked);

private:
    Ui::Task *ui;
};

#endif // TASK_H

My class Task.cpp is the following:

#include "Task.h"

#include <QInputDialog>
#include <QDebug>

Task::Task(const QString& name, QWidget *parent) :
    QWidget(parent),
    ui(new Task)
{
    ui->setupUi(this);
    setName(name);

    connect(ui->editButton, &QPushButton::clicked, this, &Task::rename);
    connect(ui->removeButton, &QPushButton::clicked, [this] {
        emit removed(this);
    });
    connect(ui->checkbox, &QCheckBox::toggled, this, &Task::checked);
}

Task::~Task()
{
    qDebug() << "~Task() called";
    delete ui;
}

void Task::setName(const QString& name)
{
    ui->checkbox->setText(name);
}

QString Task::name() const
{
    return ui->checkbox->text();
}

bool Task::isCompleted() const
{
    return ui->checkbox->isChecked();
}

void Task::rename()
{
    bool ok;
    QString value = QInputDialog::getText(this, tr("Edit task"),
                                          tr("Task name"), QLineEdit::Normal,
                                          this->name(), &ok);
    if (ok && !value.isEmpty()) {
        setName(value);
    }
}

void Task::checked(bool checked)
{
    QFont font(ui->checkbox->font());
    font.setStrikeOut(checked);
    ui->checkbox->setFont(font);

    emit statusChanged(this);
}

Thanks in Advance.

[mpergand]

@grafenocarbono
Hi,

It seems the ui definition file is missing, in your cpp file, it should have been included, maybe somthing like that:
#include "ui_task.h"

[Chris Kawa]

It's the same thing as last time.