Qt学习例子7——fileaccess

文本文件的读写

 

//filewidgets.h

 

#ifndef FILELISTWIDGET_H

#define FILELISTWIDGET_H

#include <QWidget>

#include <QFile>

#include <QPushButton>

#include <QLineEdit>

#include <QHBoxLayout>

#include <QVBoxLayout>

#include <QTextEdit>

class FileListWidget : public QWidget

{

    Q_OBJECT

public:

    explicit FileListWidget(QWidget *parent = 0);

private:

    QFile *m_file;

    QPushButton *m_btnSave;

    QPushButton *m_btnLoad;

    QTextEdit *m_txtedit;

signals:

public slots:

    void saveClicked();

    void loadClicked();

};

#endif // FILELISTWIDGET_H

 

//filewidgets.cpp

 

#include "filelistwidget.h"

#include <QTextStream>

FileListWidget::FileListWidget(QWidget *parent) :

    QWidget(parent)

  ,m_file(new QFile("listitems.txt"))

  ,m_btnSave(new QPushButton("Save"))

  ,m_btnLoad(new QPushButton("Load"))

  ,m_txtedit(new QTextEdit)

{

    QVBoxLayout *layoutAll=new QVBoxLayout;

    QHBoxLayout *bottom=new QHBoxLayout;

    bottom->addWidget(m_btnSave);

    bottom->addWidget(new QLineEdit("listitems.txt"));

    bottom->addWidget(m_btnLoad);

    layoutAll->addWidget(m_txtedit);

    layoutAll->addLayout(bottom);

    setLayout(layoutAll);

    connect(m_btnLoad,SIGNAL(clicked()),this,SLOT(loadClicked()));

    connect(m_btnSave,SIGNAL(clicked()),this,SLOT(saveClicked()));

}

void FileListWidget::saveClicked()

{

    if(!m_file->open(QIODevice::WriteOnly))//|QIODevice::Append

    {

        qDebug("Writing Error!");

        return;

    }

    else

    {

        QString content;

        content=m_txtedit->toPlainText();

        QTextStream *out=new QTextStream(m_file);

        *out<<content;

    }

    m_file->close();

}

void FileListWidget::loadClicked()

{

    m_file->open(QIODevice::ReadOnly);//|QIODevice::Text

    QTextStream *in=new QTextStream(m_file);

    QString temp(""),line;

    QStringList list;

    line=in->readLine();

    list<<line;

    temp=temp+line+"/n";

//   while(!m_file->atEnd())        //meet '/n' return eof

    while(line!=NULL)

    {

      line=in->readLine();

      temp=temp+line+"/n";

      list<<line;

    }

    m_txtedit->setPlainText(temp);

    m_file->close();

    // STL 风格的

    QStringList::const_iterator constIterator;

    for (constIterator = list.constBegin(); constIterator != list.constEnd();++constIterator)

        qDebug("Item: %s", (*constIterator).toLocal8Bit().constData());

    delete in;

}

 

//main.cpp

 

#include <QApplication>

#include "filelistwidget.h"

int main(int argc, char *argv[])

{

  QApplication a(argc, argv);

  FileListWidget *dlg=new FileListWidget;

  dlg->show();

  return a.exec();

}

 

 

程序运行结果：