Creation and call of QT dynamic DLL

One 、DLL Generation

1. Project file creation

After naming, just go to the next step .
2. Class file creation
In this example, we create 2 Classes to test
The engineering structure is as follows ：

CommonToolDll Code ：

#ifndef COMMONTOOLDLL_H
#define COMMONTOOLDLL_H

#include "commontooldll_global.h"

class COMMONTOOLDLLSHARED_EXPORT CommonToolDll
{
    

public:
    CommonToolDll();
    static double Sum(double a,double b);
};

#endif // COMMONTOOLDLL_H

#include "commontooldll.h"


CommonToolDll::CommonToolDll()
{
    
}

double CommonToolDll::Sum(double a, double b)
{
    
    return a+b;
}

PrintString Code ：

#ifndef PRINTSTRING_H
#define PRINTSTRING_H
#include<QString>
#include "commontooldll_global.h"
class COMMONTOOLDLLSHARED_EXPORT PrintString
{
    
public:
    PrintString();
    static QString PrintHexString(QByteArray str);
};
#endif // PRINTSTRING_H

#include "printstring.h"

PrintString::PrintString()
{
    

}

QString PrintString::PrintHexString(QByteArray str)
{
    
    return str.toHex();
}

matters needing attention ： Every new class has to use macros COMMONTOOLDLLSHARED_EXPORT To embellish , Otherwise, we cannot call this class later , This macro is defined in the global header file .

3. structure
Right click project engineering , Just run the build .
4. effect
What we need dll and lib Generated , This example only uses MSVC compiler , If you use MinGW It will generate at the same time .a Library file

Two 、 call

1. Create a new one Widget project
2. Environment configuration
Put the header file written at the beginning into our including In the folder

stay pro Add header file path to ：

add to lib Folder flip in dll

Import lib
Right click on the item , Select Add Library -》 External library


And then I saw pro In the document LIBS Has added , Of course, it can also be written manually

Interface test code ：

#include "widget.h"
#include "ui_widget.h"
#include"commontooldll.h"
#include"printstring.h"
#include<QDebug>
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    
    ui->setupUi(this);
}

Widget::~Widget()
{
    
    delete ui;
}

void Widget::on_pushButton_clicked()
{
    
  int a=ui->lineEdit->text().toDouble();
  int b=ui->lineEdit_2->text().toDouble();
  ui->line_sum->setText(QString::number(a+b));
  QByteArray aa("FF");
  ui->textEdit->setText(PrintString::PrintHexString(aa));
}

Running effect ：

summary ：
1. Every class needs to add an external library macro declaration , Otherwise, it cannot be called normally
2. Pay attention to the configuration header file and library file when calling
3. take dll Put it in the project file directory