QT入门笔记--Hello,World

太过爱你忘了你带给我的痛 2021-12-23 07:27 279阅读 0赞

***学C++已经有几个月了，总是研究入门书籍也不太好，于是想学点面向对象的东西，有人推荐研究MFC，但又不想把自己绑定到“有点软”（微软）平台上，于是就选了QT。总是在CSDN上发表文章，自己都有点不好意思了(害怕误导别人）。原意只是保存个人笔记的（本人手提经常重装，有时重装时忘记备份，辛辛苦苦的笔记就没了）。***

***声明：此系列笔记（应该说所有文章），只涉及对自己有用，且自己看的懂的东西，并非入门教材或者技术性类型的文章***。

**\#include <QApplication>  
\#include <QLabel>  
  
  
int main(int argc, char \*argv\[\])  
\{  
QApplication myapp(argc, argv);  
QLabel \*lbl=new QLabel("Hello,World!");  
lbl->show();  
  
 return myapp.exec();  
\}**

**运行结果：**

**![Center][]**

**解析：  
QApplication ( int & argc, char \*\* argv )：  
 Initializes the window system and constructs an application object with the command line arguments argc and argv.   
  
  
int exec () ：  
 Enters the main event loop and waits until exit() is called or the main widget is destroyed. Returns the value that was specified to exit(), which is 0 if exit() is called via quit().  
  
  
QLabel ( const char \* text, QWidget \* parent=0, const char \* name=0, WFlags f=0 )：  
 Constructs a label with a text. The label is left-aligned, vertically centered, has an automatic margin and with manual resizing.  
  
virtual void show ():  
Inherits:QLabel Inherits QFrame.QFrame Inherits QWidget.   
 Shows the widget and its child widgets.  
If its size or position has changed, Qt guarantees that a widget gets move and resize events just before the widget is shown.  
  
Tips:  
＊QApplication对象，用来管理整个应用程序所用的的资源  
＊exec()：将应用程序的控制权传给QT  
＊QT任意窗口部件都可以用作窗口。**

[Center]: /images/20211223/e3fe746d91054a4aa0a1404cba5479df.png