Analysis of QT basic engineering

main.cpp 

#include "study1.h"

#include <QApplication>

int main(int argc, char *argv[])//argc Number of command line parameters  ;argv Command line arguments 
{

    QApplication a(argc, argv);// management Qt Program operation , And set up Qt Applications , in the light of QWidewt Applications 
//    QGuiApplication a(argc, argv);// management Qt Program operation , And set up Qt Applications , For non QWidewt Applications , Such as ：QQuick
//    QCoreApplication a(argc, argv);// management Qt Program operation , And set up Qt Applications , For applications without interfaces 
    study1 w;//study1 It's our own class ;w Is the object created 
    w.show();//w object , Called show() Method , To display the interface 
    return a.exec();// Return an event cycle ,QEventLoop::exec(), Wait for mouse or keyboard input 
}

study1.cpp

#include "study1.h"
#include "ui_study1.h"
#include <QDebug>

study1::study1(QWidget *parent)// Defines an object parent;
    : QMainWindow(parent)// And then put parent As Qmainwindow Parameter initialization of ; Initialize object , Written in ： after 

    // Initialize your own variables 
    ,i(4)//i = 4// Because in study.h In file i Variables are written in ui Before the object , So initialize first 

    , ui(new Ui::study1)//ui = new UI::study1


{
    ui->setupUi(this);
    qDebug() << " Constructor executed " << endl;
}

study1::~study1()
{
    qDebug() << " Destructor executed " << endl;
    delete ui;
}

study1.h

#ifndef STUDY1_H
#define STUDY1_H

#include <QMainWindow>
#include <QtNetwork>


QT_BEGIN_NAMESPACE
namespace Ui { class study1; }
QT_END_NAMESPACE

class study1 : public QMainWindow//study1 It's our own class ,QMainWindow The public inherited study1
{
    Q_OBJECT// Uppercase is generally macro definition ; Q_OBJECT： Use Qt Signal slot , To call it 

public:
    study1(QWidget *parent = nullptr);// Constructors （ Press ctrl Click the function name , You can go in ）
    ~study1();// Destructor 

    // Declare your own variables 
    int i;

private:
    Ui::study1 *ui;// above study1 Not the same , Because different namespaces are used 
};
#endif // STUDY1_H

Runtime , perform “ Constructors ”;

When the interface is destroyed , perform “ Destructor ”

 study1.ui  // Drag and drop empty form

summary ：

1、 stay h Declare your own variables in the file

2、 Corresponding cpp Initialize your own variables in the file

 3、 And then in qDebug In the line of constructor , Add your own code

Shortcut key ：

ctr + a Future generations

ctr + i alignment

ctr + shift + ↑  Move the line up 1 That's ok

ctr + shift + ↓  Move the line down 1 That's ok

F4                  Switch between header file and source file

ctr + ←        Return to the page before jump

ctr + →        Return to the jump just now

A function is declared in the header file ： Automatically generate function body

Right click , The function body will be automatically generated

Qt Programming specification

1、 The file name should preferably be lowercase （qtcreater It's not case sensitive by itself ）

2、 Reference resources Qt Source code ：~/Qt5.12.9/5.12.9/Src

Such as ：

3、 It is found that the initials of classes are capitalized , Between words , The initial is in capital

4、 Except for constructors and destructors , The handwritten letters of member functions are all lowercase , Words and their initials are capitalized

5、 Between parameters , It is suggested to add a space

6、 Judgment statement {} Of { And if Itself in the same line ; Only one line , Can not add {};