需求
- 在本地文件中读取学生分数信息，按照一定规则显示到界面中
- 支持数据动态加载，即本地文件更改后，可以动态地在界面上显示
- ......支持分数平均等小功能
本案例采用MVC设计模式，采用四层架构，从下往上即数据层(Data Source)、数据表示层(Data Object)、数据组织层(Model)、数据显示层(View)
系统架构图:
核心类图:
DataSource类设计:
——设置数据源并读取数据
——对数据解析后生成数据对象
DataSource.h
#ifndef DATASOURCE_H
/*
*数据源
*/
#ifndef DATASOURCE_H
#define DATASOURCE_H
#include <QObject>
#include <QList>
#include "ScoreInfo.h"
class DataSource : public QObject
{
Q_OBJECT
public:
explicit DataSource(QObject *parent = 0);
/*
* @bref: 设置数据源
* @param: 数据源路径(此处为待处理文本文件路径)
* @return: 成功返回true，反之false
*/
bool setDataPath(QString path);
/*
* @bref: 导出数据
* @param 无
* @return: QList<ScoreInfo>，数据对象列表
*/
QList<ScoreInfo> fetchData();
/*
* @bref: 返回数据条数
* @param: 无
* @return: 数据条数
*/
int count();
private:
/*
* @bref: 解析从数据源读取的数据
* @param 数据在文本中的行数，info为存取该条数据的对象，这里这里info一个引用，是输出
* @return: 成功返回true，反之false
*/
bool parse(QString line/*in*/, ScoreInfo& info/*out*/);
private:
QList<ScoreInfo> m_data;//存放解析来的数据
};
#endif // DATASOURCE_H
DataSource.cpp
#include <QDir>
#include <QTextStream>
#include "DataSource.h"
DataSource::DataSource(QObject *parent) : QObject(parent)
{
}
bool DataSource::setDataPath(QString path)
{
bool ret = true;
QFile file(path);
if(file.open(QIODevice::ReadOnly | QIODevice::Text))//只读方式打开文本
{
QTextStream in(&file);//以"流"的方式读取文件
while(!in.atEnd())
{
ScoreInfo info;
if(parse(in.readLine(), info)) //调用parse解析
{
m_data.append(info);
}
}
file.close();
}
else
{
ret = false;
}
return ret;
}
QList<ScoreInfo> DataSource::fetchData()
{
QList<ScoreInfo> ret = m_data;
m_data.clear(); //这一步主要是考虑到取出数据之后，这个容器的数据就不再使用，故清除。节省空间(如果数据来自网络)
return ret;
}
int DataSource::count()
{
return m_data.count();
}
bool DataSource::parse(QString line, ScoreInfo &info)
{
bool ret = true;
QStringList list = line.split(",", QString::SkipEmptyParts);//以","分割数据，去除空格
if(list.count() == 3)
{
QString name = list[0].trimmed();
QString course = list[1].trimmed();
QString score = list[2].trimmed();
int value = score.toInt(&ret);
if(ret && (0 <= value && value <= 150))
{
info = ScoreInfo(name, course, value);//因为有这一步,故ScoreInfo需要重载=操作符
}
else
{
ret = false;
}
}
else
{
ret = false;
}
return ret;
}
ScoreInfo类的设计:
——封装数据源中的一组完整数据
——暴露返回具体数值的接口函数
ScoreInfo.h
#ifndef SCOREINFO_H
#define SCOREINFO_H
#include <QObject>
#include <QString>
class ScoreInfo : public QObject
{
Q_OBJECT
public:
explicit ScoreInfo(QObject *parent = 0);
explicit ScoreInfo(QString name, QString course, int score, QObject *parent = 0);
ScoreInfo(const ScoreInfo& obj);
ScoreInfo& operator =(const ScoreInfo& obj);
inline QString getName() const {return m_name;}
inline QString getCourse() const {return m_course;}
inline int getScore() const {return m_score;}
private:
QString m_name; //姓名
QString m_course; //科目
int m_score; //分数
};
#endif // SCOREINFO_H
ScoreInfo.cpp
#include "ScoreInfo.h"
ScoreInfo::ScoreInfo(QObject *parent) : QObject(parent)
{
}
ScoreInfo::ScoreInfo(QString name, QString course, int score, QObject *parent)
{
m_name = name;
m_course = course;
m_score = score;
}
ScoreInfo::ScoreInfo(const ScoreInfo &obj)
{
m_name = obj.m_name;
m_course = obj.m_course;
m_score = obj.m_score;
}
ScoreInfo& ScoreInfo :: operator =(const ScoreInfo &obj)
{
if(this != &obj)
{
m_name = obj.m_name;
m_course = obj.m_course;
m_score = obj.m_score;
}
return *this;
}
ScoreInfoModel类的设计:
——使用标准模型类QStandardItemModel作为成员变量
——使用前面的ScoreInfo类对象为最小单位组织数据
ScoreInfoModel.h
#ifndef SCOREINFOMODEL_H
#define SCOREINFOMODEL_H
#include <QStandardItemModel>
#include <QList>
#include <QTableView>
#include <QStandardItem>
#include <QTableView>
#include "ScoreInfo.h"
class ScoreInfoModel : public QObject
{
public:
ScoreInfoModel();
/*
* @brief:设置视图
* @param:view 外部定义的视图的引用
* @return:无
*/
void setView(QTableView& view);
/*
* @brief:添加一条数据
* @param:view info一条数据
* @return:成功返回true
*/
bool addData(ScoreInfo info);
/*
* @brief:添加数据链
* @param:view infos数据链
* @return:成功返回true
*/
bool addData(QList<ScoreInfo> infos);
/*
* @brief:移除数据
* @param:view i欲移除对象的下标索引
* @return:成功返回true
*/
bool remove(int i);
/*
* @brief:获取一条数据
* @param:view i欲获取对象的下标索引
* @return:返回欲获取的对象
*/
ScoreInfo getItem(int i);
/*
* @brief:当前有多少行数据
* @param:view 无
* @return:数据行数
*/
int count();
void clear();
private:
QStandardItemModel m_model;
};
#endif // SCOREINFOMODEL_H
ScoreInfoModel.cpp
#include "ScoreInfoModel.h"
ScoreInfoModel::ScoreInfoModel()
{
}
void ScoreInfoModel::setView(QTableView& view)
{
view.setModel(&m_model);
}
bool ScoreInfoModel::addData(ScoreInfo info)
{
bool ret = true;
QStandardItem* root = m_model.invisibleRootItem();//获取虚结点
QStandardItem* item0 = new QStandardItem();
QStandardItem* item1 = new QStandardItem();
QStandardItem* item2 = new QStandardItem();
if((root != nullptr) && (item0 != nullptr) && (item1 != nullptr) && (item2 != nullptr))
{
item0->setData(info.getName(), Qt::DisplayRole);
item1->setData(info.getCourse(), Qt::DisplayRole);
item2->setData(info.getScore(), Qt::DisplayRole);
int rowIndex = count();
root->setChild(rowIndex, 0, item0);
root->setChild(rowIndex, 1, item1);
root->setChild(rowIndex, 2, item2);
}
else
{
ret = false;
}
return ret;
}
bool ScoreInfoModel::addData(QList<ScoreInfo> infos)
{
bool ret = true;
for(int i=0; i != infos.count(); i++)
{
ret = ret && addData(infos[i]);
}
return ret;
}
bool ScoreInfoModel::remove(int i)
{
bool ret = false;
if(i >= 0 && i < count())
{
m_model.removeRow(i);
}
return ret;
}
ScoreInfo ScoreInfoModel::getItem(int i)
{
ScoreInfo ret;
if(i >= 0 && i < count())
{
QModelIndex index0 = m_model.index(i, 0, QModelIndex());
QModelIndex index1 = m_model.index(i, 1, QModelIndex());
QModelIndex index2 = m_model.index(i, 2, QModelIndex());
QVariant v0 = index0.data(Qt::DisplayRole);
QVariant v1 = index1.data(Qt::DisplayRole);
QVariant v2 = index2.data(Qt::DisplayRole);
ret = ScoreInfo(v0.toString(), v1.toString(), v2.toInt());
}
return ret;
}
int ScoreInfoModel::count()
{
return m_model.rowCount();
}
void ScoreInfoModel::clear()
{
m_model.clear();
}
最后是数据交互时序图:
1.通过setDataPath()设置数据源
2.通过read()从数据源读取数据
3.通过parse()解析数据
4.通过fetchData()返回数据
5.调用add()添加数据到模型中去
其他文件:
数据源文件(位于源文件同级目录下):
test.txt：
Tom,C++,90 Jim,Java,89 Luna,Python,99 Nancy,Go,97
Qt Creator工程文件
StdScore.pro
#-------------------------------------------------
#
# Project created by QtCreator 2018-03-15T21:48:11
#
#-------------------------------------------------
QT += core gui
CONFIG += c++11
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = StdScore
TEMPLATE = app
# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS
# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000 # disables all the APIs deprecated before Qt 6.0.0
SOURCES += main.cpp\
ScoreInfoModel.cpp \
ScoreInfo.cpp \
DataSource.cpp \
Widget.cpp
HEADERS += \
ScoreInfoModel.h \
ScoreInfo.h \
DataSource.h \
Widget.h
主界面文件:
Widget.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QWidget>
#include <QTableView>
#include <QPushButton>
#include <QMenu>
#include "DataSource.h"
#include "ScoreInfo.h"
#include "ScoreInfoModel.h"
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = 0);
~Widget();
protected:
bool eventFilter(QObject* obj, QEvent* evt);
private://界面相关
QTableView m_view; //视图, view
ScoreInfoModel m_model; //模型, model
QPushButton m_refreshBtn;
QPushButton m_clearBtn;
QPushButton m_scoreBtn;
QMenu m_menu;
private slots:
void onRefreshBtnClicked();
void onClearBtnClicked();
void onScoreBtnClicked();
void onDeleteActionClicked();
private:
DataSource m_source; //数据源
QList<ScoreInfo> m_infos; //存放组装好的数据信息
};
#endif // MAINWINDOW_H
Widget.cpp
#include <QDebug>
#include <QMessageBox>
#include "Widget.h"
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
#if 0
m_view.setParent(this);
m_view.resize(width(), height());
if(m_source.setDataPath("../StdScore/test.txt"))
{
m_infos = m_source.fetchData();
for(int i = 0; i != m_infos.size(); i++)
{
m_model.addData(m_infos[i]);
}
m_model.setView(m_view);
}
#endif
m_view.setParent(this);
m_view.move(10, 10);
m_view.resize(345, 180);
m_view.setSelectionBehavior(QAbstractItemView::SelectRows);
m_view.installEventFilter(this);
m_refreshBtn.setParent(this);
m_refreshBtn.move(10, 200);
m_refreshBtn.resize(95, 30);
m_refreshBtn.setText("Refresh");
m_clearBtn.setParent(this);
m_clearBtn.move(135, 200);
m_clearBtn.resize(95, 30);
m_clearBtn.setText("Clear");
m_scoreBtn.setParent(this);
m_scoreBtn.move(260, 200);
m_scoreBtn.resize(95, 30);
m_scoreBtn.setText("Info");
m_menu.addAction("Delete");
m_model.setView(m_view);
connect(&m_refreshBtn, SIGNAL(clicked()), this, SLOT(onRefreshBtnClicked()));
connect(&m_clearBtn, SIGNAL(clicked()), this, SLOT(onClearBtnClicked()));
connect(&m_scoreBtn, SIGNAL(clicked()), this, SLOT(onScoreBtnClicked()));
connect(m_menu.actions()[0], SIGNAL(triggered()), this, SLOT(onDeleteActionClicked()));
onRefreshBtnClicked();
}
Widget::~Widget()
{
}
bool Widget::eventFilter(QObject *obj, QEvent *evt)
{
if( (obj == &m_view) && (evt->type() == QEvent::ContextMenu) )
{
m_menu.exec(cursor().pos());
}
return QWidget::eventFilter(obj, evt);
}
void Widget::onRefreshBtnClicked()
{
DataSource source;
m_model.clear();
if( source.setDataPath("../StdScore/test.txt") )
{
m_model.addData(source.fetchData());
}
else
{
QMessageBox::critical(this, "Error", "Data source read error!", QMessageBox::Ok);
}
}
void Widget::onClearBtnClicked()
{
m_model.clear();
}
void Widget::onScoreBtnClicked()
{
int min = 256;
int max = 0;
int average = 0;
if( m_model.count() > 0 )
{
for(int i=0; i<m_model.count(); i++)
{
ScoreInfo info = m_model.getItem(i);
if( info.getScore() < min )
{
min = info.getScore();
}
if( info.getScore() > max )
{
max = info.getScore();
}
average += info.getScore();
}
average /= m_model.count();
QMessageBox::information(this, "Statistic", QString().sprintf("Min: %d\nMax: %d\nAverage: %d", min, max, average), QMessageBox::Ok);
}
else
{
QMessageBox::information(this, "Statistic", "No data record!", QMessageBox::Ok);
}
}
void Widget::onDeleteActionClicked()
{
m_model.remove(m_view.currentIndex().row());
}
mian.cpp
#include "Widget.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Widget w;
w.show();
return a.exec();
}
运行结果:
扩展:
——可以再引入委托对不同数据的显示做变换
——可以再添加一个从界面编辑回写到数据源的功能，在实际应用中可以根据当前用户的权限来判断是否能使用该功能