qt5之数据流

港控/mmm° 2022-01-21 10:59 336阅读 0赞

1，qt5中的datastream

#include "widget.h"
    #include "ui_widget.h"
    #include <QDataStream>
    #include <QTextStream>
    #include <QFile>
    #include <QDebug>
    #define cout qDebug() << "[" << __FILE__ <<":" << __LINE__ << "]"
    
    Widget::Widget(QWidget *parent) :
        QWidget(parent),
        ui(new Ui::Widget)
    {
        ui->setupUi(this);
    
        writeData();
        readData();
    }
    
    Widget::~Widget()
    {
        delete ui;
    }
    
    void Widget::writeData()
    {
        //创建文件对象
        QFile file("../test.txt");
    
        //打开文件， 只写方式打开
        bool isOk = file.open(QIODevice::WriteOnly);
        if(true == isOk)
        {
            //创建数据流，和file文件关联
            //往数据流中写数据，相当于往文件里写数据
            QDataStream stream(&file);
    
            stream << QString("主要看气质") << 250;
    
            file.close();
    
        }
    
    }
    
    void Widget::readData()
    {
        //创建文件对象
        QFile file("../test.txt");
    
        //打开文件， 只读方式打开
        bool isOk = file.open(QIODevice::ReadOnly);
        if(true == isOk)
        {
            //创建数据流，和file文件关联
            //往数据流中读数据，相当于往文件里读数据
            QDataStream stream(&file);
            //读的时候，按写的顺序取数据
            QString str;
            int a;
            stream >> str >> a;
            //qDebug() << str.toUtf8().data() << a;
            cout << str.toUtf8().data() << a;
    
            file.close();
    
        }
    }

2,textstream

#include "widget.h"
    #include "ui_widget.h"
    #include <QTextStream>
    #include <QFile>
    #include <QDebug>
    #include <QFileDialog>
    #include <QBuffer>
    #define cout qDebug() << "[" << __FILE__ <<":" << __LINE__ << "]"
    
    Widget::Widget(QWidget *parent) :
        QWidget(parent),
        ui(new Ui::Widget)
    {
        ui->setupUi(this);
        writeData();
    
        readData();
    }
    
    Widget::~Widget()
    {
        delete ui;
    }
    
    void Widget::writeData()
    {
        QFile file;
        file.setFileName("../demo.txt");
    
        bool isOk = file.open(QIODevice::WriteOnly);
        if(true == isOk)
        {
            QTextStream stream(&file);
            //指定编码
            stream.setCodec("UTF-8");
    
            stream << QString("主要看气质") << 250;
    
            file.close();
        }
    }
    
    void Widget::readData()
    {
        QFile file;
        file.setFileName("../demo.txt");
    
        bool isOk = file.open(QIODevice::ReadOnly);
        if(true == isOk)
        {
            QTextStream stream(&file);
            //指定编码
            stream.setCodec("UTF-8");
            QString str;
            int a;
            stream >> str >> a;
    
            cout << str.toUtf8().data() << a;
    
            file.close();
    
        }
    }
    
    void Widget::on_pushButton_clicked()
    {
        QString path = QFileDialog::getOpenFileName(this,
                 "open", "../"  );
        if(false == path.isEmpty())
        {
            QFile file;
            file.setFileName(path);
    
            bool isOk = file.open(QIODevice::ReadOnly);
            if(true == isOk)
            {
                QTextStream stream(&file);
                //指定编码
                stream.setCodec("UTF-8");
    
                QString str = stream.readAll();
                ui->textEdit->setText(str);
    
                file.close();
            }
    
        }
    
    
    }

3,QBuffer的使用：

#include "widget.h"
    #include "ui_widget.h"
    #include <QBuffer>//内存文件
    #include <QDebug>
    #include <QDataStream>
    
    Widget::Widget(QWidget *parent) :
        QWidget(parent),
        ui(new Ui::Widget)
    {
        ui->setupUi(this);
    
        QByteArray array;
        QBuffer memFile(&array); //创建内存文件
        memFile.open(QIODevice::WriteOnly);
    
        memFile.write("11111111111111111");
        memFile.write("22222222222222222222");
    
        memFile.close();
    
        qDebug() << memFile.buffer();
        qDebug() << "array" << array;
    
    
        QBuffer memFile1;
        memFile1.open(QIODevice::WriteOnly);
        QDataStream stream(&memFile1);
        stream << QString("测试") << 250;
        memFile1.close();
    
        qDebug() <<  memFile1.buffer();
    
        memFile1.open(QIODevice::ReadOnly);
        QDataStream in;
        in.setDevice(&memFile1);
        QString str;
        int a;
        in >> str >> a;
        memFile1.close();
    
        qDebug() << str.toUtf8().data() << a;
    
    }
    
    Widget::~Widget()
    {
        delete ui;
    }