QT 12月5日练习

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_NAMESPACE

class Widget : public QWidget
{
    Q_OBJECT

public:
    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