项目qt4迁移代码到qt5

并需要在pro文件里加上

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

 

 并将引用的#include <QtGui>替换为#include <QtWidgets>

C++ GUI Programming with Qt 4上一段代码，编译不能通过：

 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

finddialog.cpp: In constructor 'FindDialog::FindDialog(QWidget*)': finddialog.cpp:5:38: error: invalid use of incomplete type 'class QLabel' In file included from finddialog.cpp:2:0: finddialog.h:7:7: error: forward declaration of 'class QLabel' finddialog.cpp:6:17: error: invalid use of incomplete type 'class QLineEdit' In file included from finddialog.cpp:2:0: finddialog.h:8:7: error: forward declaration of 'class QLineEdit' finddialog.cpp:7:7: error: invalid use of incomplete type 'class QLabel' In file included from finddialog.cpp:2:0: finddialog.h:7:7: error: forward declaration of 'class QLabel' finddialog.cpp:8:48: error: invalid use of incomplete type 'class QCheckBox' In file included from finddialog.cpp:2:0: finddialog.h:6:7: error: forward declaration of 'class QCheckBox' finddialog.cpp:9:57: error: invalid use of incomplete type 'class QCheckBox' In file included from finddialog.cpp:2:0: finddialog.h:6:7: error: forward declaration of 'class QCheckBox' finddialog.cpp:10:42: error: invalid use of incomplete type 'class QPushButton'

在Qt官网wiki找到了答案：http://qt-project.org/wiki/Transition_from_Qt_4.x_to_Qt5

Change all instances of

 

1	#include <QtGui>

to

 

1	#include <QtWidgets>