##// END OF EJS Templates
Adding new example app.
Adding new example app.

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widget.cpp
147 lines | 4.9 KiB | text/x-c | CppLexer
#include "widget.h"
#include <QGridLayout>
#include <QPushButton>
#include <QLabel>
#include <QSqlQuery>
#include <qscatterseries.h>
#include <qchartview.h>
#include <qchartaxis.h>
#include <barchartseries.h>
#include <qbarcategory.h>
#include <qbarset.h>
#include <QListWidget>
QTCOMMERCIALCHART_USE_NAMESPACE
Widget::Widget(QWidget *parent)
: QWidget(parent)
{
setGeometry(100, 100, 800, 600);
// right panel layout
countrieslist = new QListWidget;
countrieslist->setSelectionMode(QAbstractItemView::MultiSelection);
yearslist = new QListWidget;
yearslist->setSelectionMode(QAbstractItemView::ExtendedSelection);
for (int i = 1990; i < 2011; i++)
yearslist->addItem(QString("%1").arg(i));
QPushButton* refreshButton = new QPushButton(tr("Refresh"));
connect(refreshButton, SIGNAL(clicked()), this, SLOT(refreshChart()));
QVBoxLayout* rightPanelLayout = new QVBoxLayout;
rightPanelLayout->addWidget(countrieslist);
rightPanelLayout->addWidget(yearslist);
rightPanelLayout->addWidget(refreshButton);
rightPanelLayout->setStretch(0, 1);
rightPanelLayout->setStretch(1, 0);
// main layout
chartArea = new QChartView(this);
chartArea->setChartTitle("GDP by country");
QGridLayout* mainLayout = new QGridLayout;
mainLayout->addWidget(chartArea, 0, 0);
mainLayout->addLayout(rightPanelLayout, 0, 1);
mainLayout->setColumnStretch(0,1);
setLayout(mainLayout);
// connect to the database
db = QSqlDatabase::addDatabase("QSQLITE");
db.setDatabaseName("gdpData");
if(!db.open())
{
qDebug() << "could not open database. SQLite db file missing (?)";
return;
}
// get the list of all countires and regions.
QSqlQuery query;
query.exec("SELECT DISTINCT country FROM gdp2");
// add the countries to the country filter
while (query.next()) {
countrieslist->addItem(query.value(0).toString());
}
// hide axis X labels
QChartAxis newAxis = chartArea->defaultAxisX();
newAxis.setLabelsVisible(false);
// newAxis.setLabelsOrientation(QChartAxis::LabelsOrientationSlide);
chartArea->setDefaultAxisX(newAxis);
}
Widget::~Widget()
{
//
db.close();
}
void Widget::refreshChart()
{
// selected countries items list is not sorted. copy the values to QStringlist and sort them.
QStringList selectedCountriesStrings;
QList<QListWidgetItem*> selectedCountriesItems = countrieslist->selectedItems();
for (int i = 0; i < selectedCountriesItems.size(); i++)
selectedCountriesStrings.append(selectedCountriesItems[i]->text());
selectedCountriesStrings.sort();
// use the sorted selected coutries list to initialize BarCategory
QBarCategory* category = new QBarCategory;
for (int i = 0; i < selectedCountriesStrings.size(); i++)
*category << selectedCountriesStrings[i];
BarChartSeries* series0 = new BarChartSeries(category);
// prepare the selected counries SQL query
QString countriesQuery = "country IN (";
for (int i = 0; i < selectedCountriesStrings.size(); i++)
{
countriesQuery.append("'" + selectedCountriesStrings[i] + "'");
if ( i < selectedCountriesStrings.size() - 1)
countriesQuery.append(",");
else
countriesQuery.append(")");
}
QSqlQuery query;
// selected years items list is not sorted. copy the values to QList<Integer> and sort them.
QList<int> selectedYearsInts;
QList<QListWidgetItem*> selectedYearsItems = yearslist->selectedItems();
for (int i = 0; i < selectedYearsItems.size(); i++)
selectedYearsInts.append(selectedYearsItems[i]->text().toInt());
qSort(selectedYearsInts);
// perform a query for each selected year
for (int i = 0; i < selectedYearsInts.size(); i++)
{
query.exec("SELECT country,gdpvalue FROM gdp2 where year=" + QString("%1").arg(selectedYearsInts[i]) + " AND " + countriesQuery);
QBarSet* barSet = new QBarSet;
// while (query.next()) {
// qDebug() << query.value(0).toString() << " : " << query.value(1).toString();
// }
query.first();
// the data for some of the coutries for some years might be missing.
// QBarChart needs bars to have same size
for (int k = 0; k < selectedCountriesStrings.size(); k++)
{
if (selectedCountriesStrings[k] == query.value(0).toString())
{
*barSet << query.value(1).toReal();
qDebug() << query.value(0).toString() << query.value(1).toReal() << " : " << QString("%1").arg(selectedYearsInts[i]);
query.next();
}
else
{
// data missing, put 0
*barSet << 0.0f;
qDebug() << "Putting 0 for Bosnia" << " : " << QString("%1").arg(selectedYearsInts[i]);
}
}
series0->addBarSet(barSet);
}
// add the serie to the chart
chartArea->addSeries(series0);
}