案例需求：利用QT线程操作，实现拷贝复制文件操作

---

代码：

myfile.h

#ifndef MYFILE_H
#define MYFILE_H

#include <QObject>
#include <QDebug>
#include <QThread>
#include <QFile>
#include <QtWidgets>
class MyFile : public QObject
{
    Q_OBJECT
public:
    explicit MyFile(QObject *parent = nullptr);
    void thread_file(QString path);
signals:
    void my_signal(); // 失败信号
    void success_signal(); // 成功信号
public slots:
};

#endif // MYFILE_H

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QDebug>
#include <QThread>
#include "myfile.h"
namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

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

private slots:
    void on_pushButton_clicked();
signals:
    void sendsignal(QString path);
private:
    Ui::Widget *ui;
    QThread *thread;
    MyFile *file;
};

#endif // WIDGET_H

myfile.cpp

#include "myfile.h"

MyFile::MyFile(QObject *parent) : QObject(parent)
{

}

void MyFile::thread_file(QString path)
{
    if(path.isEmpty()){
        qDebug()<<"取消选择"<<endl;
        emit my_signal();
        return ;
    }
    else{
        qDebug()<<path<<endl;
        QFile file(path);
        if(!file.open(QIODevice::ReadOnly)){
            qDebug()<<"读取失败";
            emit my_signal();
            return ;
        }
        QString writepath = "./writefile.cpp";
        QFile writefile(writepath);
        if(!writefile.open(QIODevice::WriteOnly|QIODevice::Truncate)){
            qDebug()<<"新建失败";
            emit my_signal();
            return ;
        }
        while(!file.atEnd()){ // 拷贝
            QByteArray buf;
            file.read(1024);
            writefile.write(buf);
        }
        // 关闭文件
        file.close();
        writefile.close();
        emit success_signal();
    }
}

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QDebug>
#include <QThread>
#include "myfile.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    thread = new QThread(this);
    file = new MyFile;
    file->moveToThread(thread);
    //connect(thread,&QThread::started,file,&MyFile::thread_file);
    connect(this,&Widget::destroyed,this,[=](){
        thread->quit();
        thread->wait();
    });
    connect(file,&MyFile::my_signal,this,[=](){ // 只能在主线程对界面进行操作
         this->ui->label->setText("COPY失败");
     });
    connect(file,&MyFile::success_signal,this,[=](){
        this->ui->label->setText("COPY完成");
    });
}

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

void Widget::on_pushButton_clicked()
{
    QString path = QFileDialog::getOpenFileName(this,tr("打开文件"),"./","Text filex(*.cpp)");
    connect(this,&Widget::sendsignal,file,&MyFile::thread_file);
    emit sendsignal(path);
    this->ui->label->setText("开始拷贝");
    thread->start();
}

ui

---

输出：