QT4和QT5

1，Qt5 fatal error: QPushButton: No such file or directory

解：Qt5的qapplication在QtWidgets模块里，和Qt4不一样，Qt4的qapplication在QtGui模块里。,

故而只需在.pro文件中加入：

QT += core guigreaterThan(QT_MAJOR_VERSION, 4): QT += widgets

这两行即可。

（http://qt-project.org/wiki/Transition_from_Qt_4.x_to_Qt5）

example compile time errors

1. error: QMainWindow: No such file or directory
2. error: QToolButton: No such file or directory
3. error: QWidget: No such file or directory

Solution

Add this in your *.pro file:

1. QT += widgets

Change all instances of

1. #include <QtGui>

to

1. #include <QtWidgets>

The code should work now, though sometimes you may require to be more explicit:

1. #include <QtWidgets/QToolButton>