Shell编写“Hello Qt”Qt程序

首先在~/qt目录下新建prac文件夹，在prac文件夹内编写c++源代码程序

$ cd ~/qt/prac
$ vim prac.cpp

#include <QApplication>
#include <QLabel>

int main(int argc, int argv[])
{
	QApplication(argc, argv);
	QLabel *label = new QLabel("Hello Qt!");
	label->show();
	return app.exec();
}

输入以下命令，生成一个与平台无关的项目文件prac.pro

qmake -project

编辑生成的prac.pro文件，添加语句greaterThan(QT_MAJOR_VERSION, 4): QT += widgets或QT += widgets，为了保持与Qt4的兼容性，建议使用前者

vim prac.pro

######################################################################
# Automatically generated by qmake (3.1) Thu Nov 14 20:22:38 2019
######################################################################
TEMPLATE = app
TARGET = prac
INCLUDEPATH += .

# You can make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# Please consult the documentation of the deprecated API in order to know
# how to port your code away from it.
# You can also select to disable deprecated APIs only up to a certain version of Q    t.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs depre    cated before Qt 6.0.0

# Input
SOURCES += prac.cpp

greaterThan(QT_MAJOR_VERSION,4):QT += widgets                                     
                                                

保存退出，然后输入以下命令，从这个项目文件生成一个与平台相关的makefile文件：

qmake prac.pro

键入make命令就可以构建该程序，然后就可以执行生成的可执行文件了

./prac