Qt下载网络图片到桌面

//pro文件添加
QT       += core gui network
//必要的三个头文件
#include <QNetworkAccessManager>//网络请求
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDesktopServices>//获取桌面地址

//.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QNetworkRequest>
#include <QDesktopServices>
#include <QFile>
#include <QLabel>
#include <QPainter>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

protected:
    void downloadImg();

protected slots:
    void replyFinished(QNetworkReply *);

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

//.m
#include "mainwindow.h"
#include "ui_mainwindow.h"