学步园

  本文主要在于总结文件读写的细节，借助于树结构来呈现出文件读写的用法和用途，当然可以用QSetting 来实现，也比较简单，但是没有下面的方法通用~重在积累！

windows下的txt文本，包括ini文件，都不能通过Tab键输入“\t”，在ubuntu下的gedit可以通过tab键输入制表符"\t"

如下文本(default.txt)：

 节点1     ***（ 名称）      ****(数据)

        12343     温度      12.3

        2345       湿度       1212  

//文件读：

#include<QtGui>

MyWidget::MyWidget()

{

QFile file("default.txt");

	file.open(QIODevice::ReadOnly);

	//dataFromFile=new QString;

	dataFromFile=file.readAll();

	file.close();

	QList<QVariant> rootData;

    rootData<<"节点"<<"类型"<<"数据";

//qDebug()<<rootData;

	rootItem = new TreeItem(rootData);

	setupModelData(dataFromFile.split(QString("\n")),rootItem);


        QTreeWidget myTreeWidget=new QTreeWidget;
       ....显示部分不在累述，根据需要可以简单实现

}

void MyWidget::setupModelData(constQStringList&lines,TreeItem*parent)

{

	QList<TreeItem*> parents;

	QList<int> indentations;

	parents<<parent;

	indentations<<0;

int number=0;

	while(number<lines.count()){

		int position=0;

        while(position<lines[number].length()){//分级目录是通过空格来确定的，这里设置每一级在上一级的基础上空4个空格，这里做的是去空格 " "

			if(lines[number].mid(position,1)!=" ")

				break;

			position++;		

		}

		QString lineData=lines[number].mid(position).trimmed();

		if(!lineData.isEmpty()){

            QStringList columnStrings=lineData.split("\t",QString::SkipEmptyParts);//去掉字符为空的部分

			QList<QVariant> columnData;

			for(int column=0;column<columnStrings.count();++column)//

				columnData<<columnStrings[column];

			if(position>indentations.last()){
//这里要好好理解下
				if(parents.last()->childCount()>0){
					parents<<parents.last()->child(parents.last()->childCount()-1);
					indentations<<position;
				}
			}
			else{
				while(position<indentations.last()&&parents.count()>0){
					parents.pop_back();
					indentations.pop_back();
				}
			}//else
			parents.last()->appendChild(new TreeItem(columnData,parents.last()));//添加结点
		}
		number++;	
	}

}



//文件写,读写很相似，但写更要注意细节
void MyWidget::writeTree()
{

	QFile file("default.txt");   
	if(!file.open(QIODevice::ReadWrite | QIODevice::Text)) {   
		qDebug()<<"Can't open the file!"<<endl;   
	}   
	file.resize(0);
	QTextStream stream(&file);
	
	int count=rootItem->childCount();
	parentItem=rootItem;
	qDebug()<<"write ....";
	for (int i=0;i<count;i++)
	{
		QList<QVariant> list=parentItem->child(i)->dataAll();
         for (int k = 0; k < 3/*list.size()*/; ++k) {
			QVariant dataItem=list.at(k);
qDebug()<<list.at(k);
     			stream<< dataItem.toString()<<"\t";		 
		 }
         QVariant dataItem=parentItem->data(0);
         stream<<dataItem.toString()<<"\t";
		list.clear();
		/*QListIterator<QVariant > k(list);
		k.toFront();
		 while (k.hasNext())
		{	QVariant dataItem=k.next();
qDebug()<<k.next();
     			stream<< dataItem.toString();
		}
		while ( !list2.isEmpty() )
  				 delete list2.takeFirst();
*/
qDebug()<<"for i...";		
		stream<<"\n";
		
		for(int j=0;j<parentItem->child(i)->childCount();j++)
		{
			stream<<QString("    ");
			QList<QVariant> list2=parentItem->child(i)->child(j)->dataAll();
             for (int m = 0; m < 4/*list2.size()*/; ++m) {
				QVariant dataItem=list2.at(m);
qDebug()<<list2.at(m);
     				stream<< dataItem.toString()<<"\t";		 
			}
             QVariant dataItem=parentItem->child(i)->data(0);
             stream<<dataItem.toString()<<"\t";
			list2.clear();
			stream<<"\n";
//qDebug()<<"\n";
		}
	}
	
	//stream.seek(readPos); 
	//stream <<line_in;
	file.flush();
	file.close();
}



TreeItem.h
#ifndef 

TREEITEM_H
#define TREEITEM_H
#include<QList>
#include<QVariant>
class TreeItem
{
public:
	TreeItem(const QList<QVariant> &data,TreeItem *parent=0);
	~TreeItem();
	void appendChild(TreeItem *child);
	void removeChild(int position);
	TreeItem *child(int row);
	int childCount() const;
	int columnCount() const;
	QVariant data(int column) const;
	int row() const;
	TreeItem *parent();
	bool m_checked;
	bool isChecked();
	void setCheckState(bool state);
	QList<QVariant> dataAll();
private:
	QList<TreeItem*> childItems;
	QList<QVariant> itemData;
	TreeItem *parentItem;
};
#endif

TreeItem.cpp
#include <QStringList>
#include "treeitem.h"
TreeItem::TreeItem(const QList<QVariant> &data,TreeItem *parent)
{
	parentItem=parent;
	itemData=data;
	QVariant dataItem=itemData.at(1);
	if(!dataItem.isNull())
		m_checked=dataItem.toBool();
	else 
		m_checked=true;
}
TreeItem::~TreeItem()
{
	qDeleteAll(childItems);
}
void TreeItem::appendChild(TreeItem *item)
{
	childItems.append(item);
}
void TreeItem::removeChild(int position)
{
	/*int k=0;
	 for (; k < childItems.size(); ++k) 
			if(childItems.at(k)==item)
				break;
	if(k<childItems.size())	
	*/
	childItems.removeAt(position);
}
TreeItem *TreeItem::child(int row)
{
	return childItems.value(row);
}
int TreeItem::childCount() const
{
	return childItems.count();
}
int TreeItem::columnCount() const
{
	return itemData.count();
}
QList<QVariant> TreeItem::dataAll()
{
	return itemData;
}
QVariant TreeItem::data(int column)const
{
	return itemData.value(column);
}
TreeItem *TreeItem::parent()
{
	return parentItem;
}
int TreeItem::row() const
{
	if(parentItem)
		return parentItem->childItems.indexOf(const_cast<TreeItem*>(this));
	return 0;
}
bool TreeItem::isChecked()
{
	return m_checked;
}
void TreeItem::setCheckState(bool state)
{
	m_checked=state;
	QVariant dataItem=itemData.at(1);
	QVariant check=QVariant(state);
    if(dataItem.isNull())
    //	itemData[1]=check;
    //else
		m_checked=true;
}