ui header file (ui_name.h) not found

Question

I've created form, saved it in project directory. And now i want to add some code. So, I've created header file:

#ifndef SORTDIALOG_H
#define SORTDIALOG_H

#include <QtWidgets/QDialog>
#include <QtWidgets/QWidget>


#include "ui_sortdialog.h"


class SortDialog: public QDialog, public Ui::SortDialog
{
    Q_OBJECT
public:
    SortDialog(QWidget *parent=0);
    void setColumnRange(QChar first, QChar last);
}

#endif // SORTDIALOG_H

during writing code Qt creator see ui_sortdialog.h, and i, for example, can see "Ui" namespace. But when i'n trying to compiler writes that ui_sortdialog.h wasn't found

C:\Qt\Qt5.1.1\Tools\QtCreator\bin\untitled2\sortdialog.h:8: error: ui_sortdialog.h: No such file or directory
 #include "ui_sortdialog.h"
                       ^

Answer 1

You created a form called sortdialog, right? If you did it using Qt Creator, it was supposed to add the following line to your project's .pro file:

FORMS += sortdialog.ui

If there is no such line, add it to the .pro file.

When a project has .ui files, a command called uic is called as part of the build process. This uic ("ui compiler") is responsible for the generation of ui_sortdialog.h, in you case.

You rarely need to call it directly, running qmake prior to make should do it for you (if the aforementioned FORMS line is in you .pro file).

Answer 2

Qt sometimes experiences difficulties when the build directory is at the same folder as the *.pro file.

I suggest making sure that your build directory is one level higher in the directory structure than the project file.

The following directory structure is prone to error:

MyProj/proj.pro
MyProj/builds/

The following directory structure will avoid this issue:

MyProj/proj.pro
MyProjBuild/

Answer 3

I had this problem. Here is what I had to fix: Make sure that sortdialog.cpp and sortdialog.ui are both in the pro file in the appropriate sections with the appropriate case (upper or lower exactly as in the file names).

Answer 4

For people who come here that don't have a .pro file and don't use qmake, but cmake:

Instead of:

add_executable(myprogram
    gui.cpp
    gui.ui
    main.cpp
)

Use:

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)

add_executable(myprogram
    gui.cpp
    gui.ui
    main.cpp
)

Or:

qt5_wrap_cpp(UI_SOURCES
    gui.cpp
)
qt5_wrap_ui(UI_HEADERS
    gui.ui
)
add_executable(myprogram
    main.cpp
    ${UI_SOURCES}
    ${UI_HEADERS}
)

FYI: The ui_gui.h header will be generated at ${CMAKE_CURRENT_BINARY_DIR}. Sources:

• unable to include a ui_form header of QT5 in cmake
• Qt 5 cmake fails with undefined reference to vtable on hello world with inc & src as subdirs