實現自定義的View，可繼承自QAbstractItemView類，對所需的純虛函數進行重定義與實現，對於QAbstractItemView類中的純虛函數，在子類中必須進行重定義，但不一定要實現，可根據需要選擇實現。
DEMO
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QStandardItem>
#include <QTableView>
#include <QMenuBar>
#include <QMenu>
#include <QAction>
#include <QSplitter>
#include "histogramview.h"
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = 0);
~MainWindow();
void creatAction();
void creatMenu();
void setupModel();
void setupView();
void openFile(QString);
public slots:
void slotOpen();
private:
QMenu *fileMenu;
QAction *openAct;
QStandardItemModel *model;
QTableView *table;
QSplitter *splitter;
HistogramView *histogram;
};
#endif // MAINWINDOW_H
histogramview.h
#ifndef HISTOGRAMVIEW_H
#define HISTOGRAMVIEW_H
#include <QAbstractItemView>
#include <QItemSelectionModel>
#include <QRegion>
#include <QMouseEvent>
#include <QList>
//自定義HistogramView類繼承自QAbstractItemView類，用於對表格數據進行柱狀圖顯示
class HistogramView:public QAbstractItemView
{
Q_OBJECT
public:
HistogramView(QWidget *parent=0);
//虛函數的聲明
//QAbstractItemView類中的純虛函數，這些純虛函數不一定要實現，可以根據
//需要選擇性的實現，但一定要聲明
QRect visualRect(const QModelIndex &index) const;
void scrollTo(const QModelIndex &index,ScrollHint hint=EnsureVisible);
//當鼠標在視圖中單擊或位置發生改變時觸發，它返回鼠標所在點的QModelIndex值，若鼠標
//處在某個數據項的區域中，則返回此數據的Index值，否則返回一個空的Index
QModelIndex indexAt(const QPoint &point) const;
//為selections賦初值
void setSelectionModel(QItemSelectionModel *selectionModel);
QRegion itemRegion(QModelIndex index);
void paintEvent(QPaintEvent *);
//柱狀統計圖可以被鼠標單擊選擇，選中后以不同的方式顯現
void mousePressEvent(QMouseEvent *event);
protected slots:
//當數據項發生改變時,此槽函數將響應
void selectionChanged(const QItemSelection &selected,const QItemSelection &deselected);
//當模型中的數據發生變更時，此槽函數響應
void dataChanged(const QModelIndex &topLeft,
const QModelIndex &bottomRight);
protected:
//虛函數聲明
QModelIndex moveCursor(QAbstractItemView::CursorAction cursorAction,
Qt::KeyboardModifiers modifiers);
int horizontalOffset() const;
int verticalOffset() const;
bool isIndexHidden(const QModelIndex &index) const;
//將位於QRect內的數據項按照SelectionFlags(描述被選擇的數據項以何種方式進行更新)
//指定的方式進行更新。
void setSelection(const QRect &rect,QItemSelectionModel::SelectionFlags flags);
QRegion visualRegionForSelection(const QItemSelection &selection) const;
private:
QItemSelectionModel *selections; //用於保存與視圖選擇項相關的內容
QList<QRegion> MRegionList; //用於保存其中某一類型柱狀圖的區域范圍，而每個區域是QList中的一個值
QList<QRegion> FRegionList;
QList<QRegion> SRegionList;
};
#endif // HISTOGRAMVIEW_H
mainwindow.cpp
#include "mainwindow.h"
#include <QFileDialog>
#include <QFile>
#include <QTextStream>
#include <QStringList>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
creatAction();
creatMenu();
setupModel();
setupView();
setWindowTitle(tr("View Example"));
resize(600,600);
}
MainWindow::~MainWindow()
{
}
void MainWindow::creatAction()
{
openAct=new QAction(tr("打開"),this);
connect(openAct,SIGNAL(triggered(bool)),
this,SLOT(slotOpen()));
}
void MainWindow::creatMenu()
{
fileMenu=new QMenu(tr("文件"),this);
fileMenu->addAction(openAct);
menuBar()->addMenu(fileMenu);
}
//新建一個model,並設置表頭數據
void MainWindow::setupModel()
{
model=new QStandardItemModel(4,4,this);
model->setHeaderData(0,Qt::Horizontal,tr("部門"));
model->setHeaderData(1,Qt::Horizontal,tr("男"));
model->setHeaderData(2,Qt::Horizontal,tr("女"));
model->setHeaderData(3,Qt::Horizontal,tr("退休"));
}
void MainWindow::setupView()
{
/*
table=new QTableView; //新建一個QTableView
table->setModel(model); //為QTableView對象設置相同的Model
QItemSelectionModel *selectionModel=new QItemSelectionModel(model);
table->setSelectionModel(selectionModel);
//連接選擇模型的selectionModel()信號與QTabelView對象的selectionChanged()槽函數
//以便使自定義的HistogramView對象中的選擇變化能夠反映到QTabelView對象的顯示中
connect(selectionModel,SIGNAL(selectionChanged(QItemSelection,
QItemSelection)),
table,SLOT(selectionChanged(QItemSelection,
QItemSelection)));
splitter=new QSplitter;
splitter->setOrientation(Qt::Vertical);
splitter->addWidget(table);
setCentralWidget(splitter);
*/
splitter=new QSplitter;
splitter->setOrientation(Qt::Vertical);
histogram=new HistogramView(splitter); //新建一個Histogram對象
histogram->setModel(model); //為HistogramView對象設置相同的Model
table=new QTableView;
table->setModel(model);
QItemSelectionModel *selectionModel=new QItemSelectionModel (model);
table->setSelectionModel(selectionModel);
histogram->setSelectionModel(selectionModel); //新建的QItemSelectionModel
//對象作為QTableView對象和HistogramView
//對象使用的選擇模型
splitter->addWidget(table);
splitter->addWidget(histogram);
setCentralWidget(splitter);
//連接槽函數，以便使QTableView對象中的選擇變化能夠反映到自定義的HistogramView對象的顯示中
connect(selectionModel,SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
table,SLOT(selectionChanged(QItemSelection,QItemSelection)));
connect(selectionModel,SIGNAL(selectionChanged(QItemSelection,QItemSelection)),
histogram,SLOT(selectionChanged(QItemSelection,QItemSelection)));
}
//slotOpne()槽函數完成打開標准文件對話框
void MainWindow::slotOpen()
{
QString name;
name=QFileDialog::getOpenFileName(this,"打開",".","histogram files(*.txt)");
if(!name.isEmpty())
{
openFile(name);
}
}
//openFile()函數完成打開所選的文件的內容
void MainWindow::openFile(QString path)
{
if(!path.isEmpty())
{
QFile file(path);
if(file.open(QFile::ReadOnly | QFile::Text))
{
QTextStream stream(&file);
QString line;
model->removeRows(0,model->rowCount(QModelIndex()),
QModelIndex());
int row=0;
do
{
line=stream.readLine();
if(!line.isEmpty())
{
model->insertRows(row,1,QModelIndex());
QStringList pieces=line.split(",",QString::SkipEmptyParts);
model->setData(model->index(row,0,QModelIndex()),
pieces.value(0));
model->setData(model->index(row,1,QModelIndex()),
pieces.value(1));
model->setData(model->index(row,2,QModelIndex()),
pieces.value(2));
model->setData(model->index(row,3,QModelIndex()),
pieces.value(3));
row++;
}
}while(!line.isEmpty());
file.close();
}
} //end if(!path.isEmpty())
}
histogramview.cpp
#include "histogramview.h"
#include <QPainter>
HistogramView::HistogramView(QWidget *parent):QAbstractItemView(parent)
{
}
//paintEvent()函數完成柱狀統計圖繪制的工作
void HistogramView::paintEvent(QPaintEvent *)
{
//以viewport()作為繪圖設備新建一個QPainter對象
QPainter painter(viewport());
painter.setPen(Qt::black);
int x0=40;
int y0=250;
/*完成了x,y坐標軸的繪制,並標注坐標軸的變量*/
//y坐標軸
painter.drawLine(x0,y0,40,30);
painter.drawLine(38,32,40,30);
painter.drawLine(40,30,42,32);
painter.drawText(20,30,tr("人數"));
for(int i=0;i<5;i++)
{
painter.drawLine(-1,-i*50,1,-i*50);
painter.drawText(-20,-i*50,tr("%1").arg(i*5));
}
//x軸
painter.drawLine(x0,y0,540,250);
painter.drawLine(538,248,540,250);
painter.drawLine(540,250,538,252);
painter.drawText(545,250,tr("部門"));
int posD=x0+20;
int row;
for(row=0;row<model()->rowCount(rootIndex());row++)
{
QModelIndex index=model()->index(row,0,rootIndex());
QString dep=model()->data(index).toString();
painter.drawText(posD,y0+20,dep);
posD+=50;
}
/*完成了表格第1列數據的柱狀統計圖的繪制*/
//男
int posM=x0+20;
MRegionList.clear();
for(row=0;row<model()->rowCount(rootIndex());row++)
{
QModelIndex index=model()->index(row,1,rootIndex());
int male=model()->data(index).toDouble();
int width=10;
//使用不同畫刷顏色區別選中與未被選中的數據項
if(selections->isSelected(index))
{
//Qt::Dense3Pattern是QBrush style
//如果被選中，則畫刷的style改變
painter.setBrush(QBrush(QColor(91,75,0,255),Qt::Dense3Pattern));
}
else
{
painter.setBrush(Qt::blue);
}
//根據當前數據項的值按照比例繪制一個方形表示此項數據
painter.drawRect(QRect(posM,y0-male*10,width,male*10));
QRegion regionM(posM,y0-male*10,width,male*10);
//將此數據所占據的區域保存到MRegionList列表中，為后面的數據項做准備
MRegionList.insert(row,regionM);
posM+=50;
} //end for(row=0;row<model()->rowCount(rootIndex());row++)
/*完成了表格第2列數據的柱狀統計圖繪制*/
//女
int posF=x0+30;
FRegionList.clear();
for(row=0;row<=model()->rowCount(rootIndex());row++)
{
QModelIndex index=model()->index(row,2,rootIndex());
int female=model()->data(index).toDouble();
int width=10;
if(selections->isSelected(index))
{
painter.setBrush(QBrush(Qt::red,Qt::Dense3Pattern));
}
else
{
painter.setBrush(Qt::red);
}
painter.drawRect(QRect(posF,y0-female*10,width,female*10));
QRegion regionF(posF,y0-female*10,width,female*10);
FRegionList.insert(row,regionF);
posF+=50;
} //end for(row=0;row<=model()->rowCount(rootIndex());row++)
/*完成了表格第3列數據的柱狀統計圖的繪制*/
//退休
int posS=x0+40;
SRegionList.clear();
for(row=0;row<=model()->rowCount(rootIndex());row++)
{
QModelIndex index=model()->index(row,3,rootIndex());
int retire=model()->data(index).toDouble();
int width=10;
if(selections->isSelected(index))
{
painter.setBrush(QBrush(Qt::green,Qt::Dense3Pattern));
}
else
{
painter.setBrush(Qt::green);
}
painter.drawRect(QRect(posS,y0-retire*10,width,retire*10));
QRegion regionS(posS,y0-retire*10,width,retire*10);
SRegionList.insert(row,regionS);
posS+=50;
} //end for(row=0;row<=model()->rowCount(rootIndex());row++)
}
//dataChanged函數實現當model中的數據更改時，調用繪圖設備的update()函數
//進行更新，反映數據的變化
void HistogramView::dataChanged(const QModelIndex &topLeft,
const QModelIndex &bottomRight)
{
QAbstractItemView::dataChanged(topLeft,bottomRight);
viewport()->update();
}
//setSelectionModel()函數為selections賦初值
void HistogramView::setSelectionModel(QItemSelectionModel *selectionModel)
{
selections=selectionModel;
}
//selectionChanged()函數中完成當數據項發生變化時調用update()函數
//重繪繪圖設備即可工作
void HistogramView::selectionChanged(const QItemSelection &selected,
const QItemSelection &deselected)
{
viewport()->update();
}
//鼠標按下事件函數mousePressEvent(),在調用setSelection()函數時確定鼠標單擊
//點是否在某個數據項的區域內，並設置選擇項
void HistogramView::mousePressEvent(QMouseEvent *event)
{
QAbstractItemView::mousePressEvent(event);
setSelection(QRect(event->pos().x(),event->pos().y(),1,1),
QItemSelectionModel::SelectCurrent);
}
void HistogramView::setSelection(const QRect &rect,
QItemSelectionModel::SelectionFlags flags)
{
int rows=model()->rowCount(rootIndex()); //獲取總行數
int columns=model()->columnCount(rootIndex()); //獲取總列數
//用於保存被選中的數據項的Index值,此處只實現了用鼠標單擊選擇，而沒有實現
//鼠標拖曳框選，因此，鼠標動作只可能選中一個數據項。若實現框選，則可使用
//QModelIndexList來保存所有被選中的數據項的Index值
QModelIndex selectedIndex;
for(int row=0;row<rows;++row)
{
for(int column=1;column<columns;++column)
{
QModelIndex index=model()->index(row,column,rootIndex());
QRegion region=itemRegion(index); //返回指定index的數據項所占用的區域
if(!region.intersected(rect).isEmpty())
selectedIndex=index;
}
}
if(selectedIndex.isValid())
selections->select(selectedIndex,flags);
else
{
QModelIndex noIndex;
selections->select(noIndex,flags);
}
}
QModelIndex HistogramView::indexAt(const QPoint &point) const
{
QPoint newPoint(point.x(),point.y());
QRegion region;
//男 列
foreach(region,MRegionList) //檢查當前點是否處於第一列(男)數據的區域中
{
if(region.contains(newPoint))
{
int row=MRegionList.indexOf(region);
QModelIndex index=model()->index(row,1,rootIndex());
return index;
}
}
//女 列
foreach(region,FRegionList)
{
if(region.contains(newPoint))
{
int row=FRegionList.indexOf(region);
QModelIndex index=model()->index(row,2,rootIndex());
return index;
}
}
//合計 列
foreach(region,FRegionList)
{
if(region.contains(newPoint))
{
int row=FRegionList.indexOf(region);
QModelIndex index=model()->index(row,2,rootIndex());
return index;
}
}
return QModelIndex();
}
QRect HistogramView::visualRect(const QModelIndex &index)const{}
void HistogramView::scrollTo(const QModelIndex &index,ScrollHint){}
QModelIndex HistogramView::moveCursor(QAbstractItemView::CursorAction cursorAction, Qt::KeyboardModifiers modifiers){}
int HistogramView::horizontalOffset()const{}
int HistogramView::verticalOffset()const{}
bool HistogramView::isIndexHidden(const QModelIndex &index)const{}
QRegion HistogramView::visualRegionForSelection(const QItemSelection & selection)const{}
QRegion HistogramView::itemRegion(QModelIndex index)
{
QRegion region;
if (index.column() == 1) //男
region = MRegionList[index.row()];
if (index.column() == 2) //女
region = FRegionList[index.row()];
if (index.column() == 3) //退休
region = SRegionList[index.row()];
return region;
}
main.cpp
#include "mainwindow.h"
#include <QApplication>
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
注意.pro文件如下
#-------------------------------------------------
#
# Project created by QtCreator 2018-09-05T19:29:45
#
#-------------------------------------------------
QT += core gui
greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
TARGET = CH803
TEMPLATE = app
DEFINES += QT_DEPRECATED_WARNINGS #新增加的
SOURCES += main.cpp\
mainwindow.cpp \
histogramview.cpp
HEADERS += mainwindow.h \
histogramview.h
在該目錄下新建文件histogram.txt
E:\QT\CH803\build-CH803-Desktop_Qt_5_6_2_MinGW_32bit-Debug
內容如下
一部,12,3,5
二部,16,4,0
三部,18,4,2
四部,10,3,1
五部,11,4,3
六部,12,2,4
七部,14,3,5
八部,9,1,1
運行效果如下
備注
這個程序里有幾個函數我還是沒搞懂，不太清楚其中的邏輯
void HistogramView::setSelection(const QRect &rect,
QItemSelectionModel::SelectionFlags flags)
QModelIndex HistogramView::indexAt(const QPoint &point) const
參考資料《Qt5開發及實例》