我決定在這寫下自己每天獲得的知識，有空可以當作翻翻的依據。內容儘管很雜。

SVG是一種用XML定義的語言，用來描述二維向量及向量/柵格圖形。

enum QIODevice::OpenModeFlag
flags QIODevice::OpenMode

This enum is used withopen() to describe the mode in which a device is opened. It is also returned byopenMode().

Constant	Value	Description
QIODevice::NotOpen	0x0000	The device is not open.
QIODevice::ReadOnly	0x0001	The device is open for reading.
QIODevice::WriteOnly	0x0002	The device is open for writing.
QIODevice::ReadWrite	ReadOnly | WriteOnly	The device is open for reading and writing.
QIODevice::Append	0x0004	The device is opened in append mode, so that all data is written to the end of the file.
QIODevice::Truncate	0x0008	If possible, the device is truncated before it is opened. All earlier contents of the device are lost.
QIODevice::Text	0x0010	When reading, the end-of-line terminators are translated to '\n'. When writing, the end-of-line terminators are translated to the local encoding, for example '\r\n' for Win32.
QIODevice::Unbuffered	0x0020	Any buffer in the device is bypassed.

QIODevice::Truncate  ;f覆蓋了原來的內容；

truncated

[英] [ˈtrʌŋkeitid] [美] [ˈtrʌŋˌketɪd] 生詞本

• 簡明釋義

• 更多資料

adj.切去頂端的，縮短了的，被刪節的

v.截面的( truncate的過去式和過去分詞 )；截頭的；縮短了的；截去頂端或末端

bypassed

• v. 繞道，忽視（bypass的過去分詞）

原始碼：寫xml檔案

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <iostream>
#include <QTextStream>
#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    QFile *file=new QFile("/home/qust/qt/XML/1.xml");
    if(!file->open(QIODevice::WriteOnly|QIODevice::ReadOnly))
    {
        return ;
    }
    QDomDocument doc;
    QDomText text;
    QDomElement element;
    QDomProcessingInstruction instruction;
    instruction=doc.createProcessingInstruction("xml","version=\'1.0\'");
    doc.appendChild(instruction);
    QDomElement root=doc.createElement("kdevelop");
    doc.appendChild(root);
    QDomElement general=doc.createElement("general");
    root.appendChild(general);

    element=doc.createElement("author");
    text=doc.createTextNode("zeki");

    element.appendChild(text);
    general.appendChild(element);

    element=doc.createElement("email");
    text=doc.createTextNode("[email protected]");
    element.appendChild(text);
    general.appendChild(element);

    QTextStream out(file);
    doc.save(out,4);
    file->close();

}

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

執行後：

讀xml原始碼：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtXml>
#include <QDebug>
#include <QFile>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QDomDocument dom;
    QFile *file=new QFile("/home/qust/qt/XML/1.xml");
    if(file->open(QIODevice::ReadOnly))
    {
        dom.setContent(file);

    }

    QDomNodeList email=dom.elementsByTagName("email");
    qDebug()<<email.count();
    qDebug()<<email.item(0).toElement().text();
    // QDomNodeList general=kdevelop.item(0).toElement().childNodes();
    //qDebug()<<general.item(0).toElement().text();
}

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