设置Qt应用程序图标

在Qt助手（assistant.exe）搜索关键字"Setting the Application Icon"就可以看到在各种平台设置Qt程序图标的方法。

Setting the Application Icon on Windows：
First, create an ICO format bitmap file that contains the icon image. This can be done with e.g. Microsoft Visual C++: Select File|New, then select the File tab in the dialog that appears, and choose Icon. (Note that you do not need to load your application into Visual C++; here we are only using the icon editor.)
Store the ICO file in your application's source code directory, for example, with the name myappico.ico. Then, create a text file called, say, myapp.rc in which you put a single line of text:
         IDI_ICON1               ICON    DISCARDABLE     "myappico.ico"
Finally, assuming you are using qmake to generate your makefiles, add this line to your myapp.pro file:
         RC_FILE = myapp.rc
Regenerate your makefile and your application. The .exe file will now be represented with your icon in Explorer.
If you do not use qmake, the necessary steps are: first, run the rc program on the .rc file, then link your application with the resulting .res file.
在VC下RC_FILE = myapp.rc这步操作可以省略。再将这个rc文件加入到VC++的项目中，然后设置它的<配置属性|资源|常规|预处理器定义>为如下：
“_WINDOWS, UNICODE, WIN32, QT_LARGEFILE_SUPPORT, QT_DLL, QT_WEBKIT_LIB, QT_XML_LIB,
QT_GUI_LIB, QT_NETWORK_LIB, QT_CORE_LIB, QT_THREAD_SUPPORT, _DEBUG”（ 这些参数的设置视情况而定）
然后编译这个*.rc文件，再编译vc项目。