base operand of '->' has non-pointer type

[mrjj]

can u check if u type
ui->
if it will suggest anything?
also, if u dblclick the UI it opens fine etc?
Also,
you do have
Ui::Notepad *ui; ?

[Nils A]

@mrjj Hello,

When I type ui it will give suggestions only after I type ::
If I choose ui::textEdit->setText(in.readAll()); I get an error,
Noteapp/notewindow.cpp:30: error: 'ui' is not a class or namespace
ui::textEdit->setText(in.readAll());
^

But, because this is an example application fron Qt on their site, why would they make it with errors? Do they test these apps?

Nils A.

[Nils A]

Here the files: noteapp.pro, notewindow.h and notewindow.ccp

// noteapp.pro
#-------------------------------------------------

Project created by QtCreator 2015-12-27T20:58:35

why is this so big??

#-------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = Noteapp
TEMPLATE = app

SOURCES += main.cpp
notewindow.cpp

HEADERS += notewindow.h

FORMS += notewindow.ui

---

// notewindow.h
#ifndef NOTEWINDOW_H
#define NOTEWINDOW_H

#include "ui_notewindow.h"

class NoteWindow : public QMainWindow
{
Q_OBJECT

public:
explicit NoteWindow(QWidget *parent = 0);

private slots:
void on_quitButton_clicked();

void on_actionOpen_triggered();

void on_actionSave_triggered();

private:
Ui::NoteWindow ui;
};

#endif // NOTEWINDOW_H

---

// notewindow.ccp

#include "notewindow.h"
#include <QFileDialog>
#include <QFile>
#include <QMessageBox>
#include <QTextStream>

NoteWindow::NoteWindow(QWidget *parent) :
QMainWindow(parent)
{
ui.setupUi(this);
}

void NoteWindow::on_quitButton_clicked()
{
qApp->quit();
}

void NoteWindow::on_actionOpen_triggered()
{
QString fileName = QFileDialog::getOpenFileName(this, tr("Open File"), QString(),
tr("Text Files (.txt);;C++ Files (.cpp *.h)"));

  if (!fileName.isEmpty()) {
      QFile file(fileName);
      if (!file.open(QIODevice::ReadOnly)) {
          QMessageBox::critical(this, tr("Error"), tr("Could not open file"));
          return;
      }
      QTextStream in(&file);
      ui->textEdit->setText(in.readAll());
      file.close();

      //error: base operand of '->' has non-pointer type 'Ui::NoteWindow'
      //         ui->textEdit->setText(in.readAll());
      //             ^
  }

}

void NoteWindow::on_actionSave_triggered()
{
QString fileName = QFileDialog::getSaveFileName(this, tr("Save File"), QString(),
tr("Text Files (.txt);;C++ Files (.cpp *.h)"));

if (!fileName.isEmpty()) {
    QFile file(fileName);
    if (!file.open(QIODevice::WriteOnly)) {
        // error message
    } else {
        QTextStream stream(&file);
        stream << ui->textEdit->toPlainText();
        stream.flush();
        file.close();
    }
}

}

[SGaist]

ui is not a pointer so you should use ui.textEdit->toPlainText()

[Nils A]

Yes, that's it! You are great. Why would Qt make this mistake in their example code?

thanks,
Nils A.

[SGaist]

There's no mistake in the example, please read again the Notepad class. In the header they are declaring a pointer for ui and the initialization also shows they are allocating a new instance of Ui::Notepad in the constructor member initializer list

[Nils A]

Thanks again, but the example on the site really uses the -> and not a .

QTextStream in(&file);
ui->textEdit->setText(in.readAll());
file.close();

see http://doc.qt.io/qt-5/gettingstartedqt.html

[SGaist]

Yes, and again the example is correct.

Your code is a bit different: you have ui as Ui::Notepad ui;. In the example it's Ui::Notepad *ui;

[Nils A]

I see yes, but still strange (and an error) because the (in my case) NoteWindow class is created by the Qt-widget wizard. I did not type the code.

example code on the site;
#include <QMainWindow>

namespace Ui {
class Notepad;
}

class Notepad : public QMainWindow
{
Q_OBJECT

public:
explicit Notepad(QWidget *parent = 0);
~Notepad();

private:
Ui::Notepad *ui;
};

======
example created by the Qt-Wizard:

#ifndef NOTEWINDOW_H
#define NOTEWINDOW_H

#include "ui_notewindow.h"

class NoteWindow : public QMainWindow
{
Q_OBJECT

public:
explicit NoteWindow(QWidget *parent = 0);

private:
Ui::NoteWindow ui;
};

#endif // NOTEWINDOW_H

[Nils A]

@SGaist Thanks again Champ. You are right, there is no error in the example. The mixing of the example code (using the *) with the auto-generate code (not using the *) made my C++ virgin brain confused. But now I will never forget to check for *'s any more.
Have a good day! (now how to set this to solved?) (Ah, found this too. Solved!)