使用QT的文件IO QFile 和 QFileDialog文件对话框，读取一个选中的文件，然后使用QSlider显示读取的进度，QSlider需要改成进度条的样式
widget.cpp
#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);ui->horizontalSlider->setRange(0,100);QString qss="QSlider::sub-page:horizontal{background-color:rgb(0,255,0,255)}QSlider::groove::horizontal{background-color:gray}";ui->horizontalSlider->setStyleSheet(qss);timer=new QTimer(this);}Widget::~Widget()
{delete ui;
}void Widget::readData(const QString &filename)
{file_src.setFileName(filename);file_src.open(QIODevice::ReadOnly);if(file_src.exists()==false){qDebug() << "文件不存在";return ;}if(data.size()>=file_src.size()){i=0;ui->horizontalSlider->setValue(i);timer->stop();return ;}QByteArray temp=file_src.read(100);data+=temp;i=static_cast<int>(static_cast<double>(data.size())/file_src.size()*100);qDebug() << i;ui->horizontalSlider->setValue(i);qDebug() << data.size();//QString str=QString::fromLocal8Bit(arr);file_src.close();
}void Widget::writeData(const QString &filename, const QByteArray &data)
{file_des.setFileName(filename);file_des.open(QIODevice::WriteOnly);//QByteArray arr=data.toLocal8Bit();file_des.write(data);file_des.close();qDebug() << "文件保存成功";
}void Widget::on_pushButton_clicked()
{path_src=QFileDialog::getOpenFileName(this,"打开文件","C:/Users/pzctj/Desktop/qtimage","Images (*.png *.xpm *.jpg *.bmp);;Text files (*.txt);;All files (*.*)");//qDebug() << str;timer->start(100);QObject::connect(timer,&QTimer::timeout,this,&Widget::ontimeOut);
}void Widget::on_pushButton_2_clicked()
{path_des=QFileDialog::getSaveFileName(this,"保存文件","C:/Users/pzctj/Desktop/qtimage","Images (*.png *.xpm *.jpg *.bmp);;Text files (*.txt);;All files (*.*)");qDebug() << path_des;}void Widget::ontimeOut()
{readData(path_src);
}widget.h
#ifndef WIDGET_H
#define WIDGET_H#include <QWidget>
#include <QFileDialog>
#include <QDebug>
#include <QFile>
#include <synchapi.h>
#include <cstdlib>
#include <QTimer>QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACEclass Widget : public QWidget
{Q_OBJECTpublic:Widget(QWidget *parent = nullptr);~Widget();void readData(const QString& filename);void writeData(const QString& filename,const QByteArray& data);private slots:void on_pushButton_clicked();void on_pushButton_2_clicked();
public slots:void ontimeOut();
private:Ui::Widget *ui;QFile file_src;//用于读取文件QFile file_des;//用于写文件QByteArray data;//用于暂时接收文件内容int i=0;//用于记录进度条QTimer* timer;QString path_src;QString path_des;
};
#endif // WIDGET_H
