Qt编程中qmake的使用详解

首先说一下qt编程的步骤，然后再仔细说一下qmake的使用。我看书上的都是编写好cpp文件后，分别执行命令: qmake -project、qmake、make，然后执行就可以了，但是要是我在一个文件夹下有多个cpp文件，qmake怎么识别？make生成的最后执行文件的名，我怎么能随心所欲的自己定？带着疑问，找了网上的资料，不如所衣，然后尝试着gcc编译的思想竟然撞到了。

  其实我感觉要要真正了解qmake的使用方法，直接在终端下输入命令：qmake -help就可以了，我也是这样做的，帮助内容如下

Usage: qmake [mode] [options] [files]

QMake has two modes, one mode for generating project files based on
some heuristics, and the other for generating makefiles. Normally you
shouldn't need to specify a mode, as makefile generation is the default
mode for qmake, but you may use this to test qmake on an existing project

Mode:
  -project       Put qmake into project file generation mode
                 In this mode qmake interprets files as files to
                 be built,
                 defaults to *.c; *.ui; *.y; *.l; *.ts; *.xlf; *.qrc; *.h; *.hpp; *.hh; *.hxx; *.H; *.cpp; *.cc; *.cxx; *.C
                 Note: The created .pro file probably will 
                 need to be edited. For example add the QT variable to 
                 specify what modules are required.
  -makefile      Put qmake into makefile generation mode (default)
                 In this mode qmake interprets files as project files to
                 be processed, if skipped qmake will try to find a project
                 file in your current working directory

Warnings Options:
  -Wnone         Turn off all warnings; specific ones may be re-enabled by
                 later -W options
  -Wall          Turn on all warnings
  -Wparser       Turn on parser warnings
  -Wlogic        Turn on logic warnings (on by default)
  -Wdeprecated   Turn on deprecation warnings (on by default)

Options:
   * You can place any variable assignment in options and it will be     *
   * processed as if it was in [files]. These assignments will be parsed *
   * before [files].                                                     *
  -o file        Write output to file
  -d             Increase debug level
  -t templ       Overrides TEMPLATE as templ
  -tp prefix     Overrides TEMPLATE so that prefix is prefixed into the value
  -help          This help
  -v             Version information
  -after         All variable assignments after this will be
                 parsed after [files]
  -norecursive   Don't do a recursive search
  -recursive     Do a recursive search
  -set <prop> <value> Set persistent property
  -unset <prop>  Unset persistent property
  -query <prop>  Query persistent property. Show all if <prop> is empty.
  -cache file    Use file as cache           [makefile mode only]
  -spec spec     Use spec as QMAKESPEC       [makefile mode only]
  -nocache       Don't use a cache file      [makefile mode only]
  -nodepend      Don't generate dependencies [makefile mode only]
  -nomoc         Don't generate moc targets  [makefile mode only]
  -nopwd         Don't look for files in pwd [project mode only]
song@ubuntu:~/lianxi/qt$ clear

song@ubuntu:~/lianxi/qt$ qmake -help
Usage: qmake [mode] [options] [files]

QMake has two modes, one mode for generating project files based on
some heuristics, and the other for generating makefiles. Normally you
shouldn't need to specify a mode, as makefile generation is the default
mode for qmake, but you may use this to test qmake on an existing project

Mode:
  -project       Put qmake into project file generation mode
                 In this mode qmake interprets files as files to
                 be built,
                 defaults to *.c; *.ui; *.y; *.l; *.ts; *.xlf; *.qrc; *.h; *.hpp; *.hh; *.hxx; *.H; *.cpp; *.cc; *.cxx; *.C
                 Note: The created .pro file probably will 
                 need to be edited. For example add the QT variable to 
                 specify what modules are required.
  -makefile      Put qmake into makefile generation mode (default)
                 In this mode qmake interprets files as project files to
                 be processed, if skipped qmake will try to find a project
                 file in your current working directory

Warnings Options:
  -Wnone         Turn off all warnings; specific ones may be re-enabled by
                 later -W options
  -Wall          Turn on all warnings
  -Wparser       Turn on parser warnings
  -Wlogic        Turn on logic warnings (on by default)
  -Wdeprecated   Turn on deprecation warnings (on by default)

Options:
   * You can place any variable assignment in options and it will be     *
   * processed as if it was in [files]. These assignments will be parsed *
   * before [files].                                                     *
  -o file        Write output to file
  -d             Increase debug level
  -t templ       Overrides TEMPLATE as templ
  -tp prefix     Overrides TEMPLATE so that prefix is prefixed into the value
  -help          This help
  -v             Version information
  -after         All variable assignments after this will be
                 parsed after [files]
  -norecursive   Don't do a recursive search
  -recursive     Do a recursive search
  -set <prop> <value> Set persistent property
  -unset <prop>  Unset persistent property
  -query <prop>  Query persistent property. Show all if <prop> is empty.
  -cache file    Use file as cache           [makefile mode only]
  -spec spec     Use spec as QMAKESPEC       [makefile mode only]
  -nocache       Don't use a cache file      [makefile mode only]
  -nodepend      Don't generate dependencies [makefile mode only]
  -nomoc         Don't generate moc targets  [makefile mode only]
  -nopwd         Don't look for files in pwd [project mode only]

qmake命令格式

   qmake [mode] [options] [files]

mode选项

   -project  生成.pro文件

   -makefile 生成Makefile文件

options选项(这里介绍几个常用的，其它的自己去翻译上面,其实我也是刚学，用到的时候再学习哈)

  -o file 输出文件名，比如qmake -project  hello.cpp -o  hello.pro，就会生成一个hello.pro文件，如果是qmake -project  hello.cpp -o  hello11.pro，就会生成一个hello11.pro文件

实验1

 1、编写代码，命名为hello.cpp，如下

 hello.cpp代码如下

#include<qapplication.h>
#include<qpushbutton.h>

int main(int argc,char *argv[])
{
    QApplication a(argc,argv);
    QPushButton hellobtn("Hello World!",0);
    hellobtn.resize(200,50);
    hellobtn.show();
    return a.exec();
}

 2、qmake -project (用于创建.pro文件，将所有的文件编译成一个与平台无关的工程文件)

 可见默认生成的文件名为 qt.pro

 3、qmake (读取本身的Qt设置，生成与库一致的相应的Makefile)

 4、make (根据生成的Makefile，将文件编译为二进制可执行程序)   

  可见生成了qt可执行程序

5、执行命令：./qt

实验2

本实验中并没有用到上面所讲的方式，而是直接使用了默认值，但是假设说该文件夹下有两个cpp文件，如下图

这时候再执行命令：qmake -project会怎么样呢？会出现下面的结果

有点意思，竟然不出错，但是你知道它生成的qt.pro是哪个cpp文件的吗？我不知道，加入这里我想对test.cpp操作，这时候就要按照上面的格式了。

1、qmake -project test.cpp -o test.pro

 这时候生成了test.pro

2、qmake  -makefile test.pro，这里生成test.pro的Makefile

3、make

4、执行命令 ./test