User talk:Nelson Barata

2012-09-25T07:46:29Z

Nelson Barata:

'''Welcome to ''ProgrammingExamples''!'''
We hope you will contribute much and well.
You will probably want to read the [[Help:Contents|help pages]].
Again, welcome and have fun! [[User:Daviddoria|Daviddoria]] 13:55, 12 September 2012 (UTC)

Hi Nelson! Thanks for your first contribution!! Could I ask you to leave a brief not in the "Summary" of the changes/additions you make? This way when I come along and check them out, I can see "ah, it is better to create the object on the heap instead of pass the address of an object on the stack because...". Keep the contributions coming! [[User:Daviddoria|Daviddoria]] 14:08, 12 September 2012 (UTC)

Ok, I just found the "summary" field when editing a page. Will think about it for futures contributions. [[User:Nelson Barata|Nelson Barata]] 09:44, 25 September 2012 (GMT)

Talk:Qt/Delegates/ComboBoxDelegate

2012-09-12T14:09:41Z

Nelson Barata: Created page with 'In the main function: allocating de ComboBoxDelegate on the heap rather than the stack. Second method didn't worked for me.'

In the main function:
allocating de ComboBoxDelegate on the heap rather than the stack.
Second method didn't worked for me.

Qt/Delegates/ComboBoxDelegate

2012-09-12T14:05:57Z

Nelson Barata: /* main.cpp */

==main.cpp==
<source lang="cpp">
#include <QApplication>
#include <QHeaderView>
#include <QItemSelectionModel>
#include <QStandardItemModel>
#include <QTableView>

#include <iostream>

#include "ComboBoxDelegate.h"

int main(int argc, char *argv[])
{
std::cout << "Enter." << std::endl;
QApplication app(argc, argv);

QStandardItemModel model(4, 2);
QTableView tableView;
tableView.setModel(&model);

ComboBoxDelegate* delegate = new ComboBoxDelegate(this);
//tableView.setItemDelegate(&delegate);
tableView.setItemDelegateForColumn(1, delegate); // Column 0 can take any value, column 1 can only take values up to 8.

for (int row = 0; row < 4; ++row)
{
for (int column = 0; column < 2; ++column)
{
QModelIndex index = model.index(row, column, QModelIndex());
int value = (row+1) * (column+1);
std::cout << "Setting (" << row << ", " << column << ") to " << value << std::endl;
model.setData(index, QVariant(value));
}
}

// Make the combo boxes always displayed.
for ( int i = 0; i < model.rowCount(); ++i )
{
tableView.openPersistentEditor( model.index(i, 1) );
}

tableView.show();
return app.exec();
}

</source>

==ComboBoxDelegate.h==
<source lang="cpp">
#ifndef COMBOBOXDELEGATE_H
#define COMBOBOXDELEGATE_H

#include <string>
#include <vector>

#include <QItemDelegate>

class QModelIndex;
class QWidget;
class QVariant;

class ComboBoxDelegate : public QItemDelegate
{
Q_OBJECT
public:
ComboBoxDelegate(QObject *parent = 0);

QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const;
void setEditorData(QWidget *editor, const QModelIndex &index) const;
void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const;
void updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &index) const;
void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const;

private:
std::vector<std::string> Items;

};
#endif

</source>

==ComboBoxDelegate.cpp==
<source lang="cpp">
#include "ComboBoxDelegate.h"

#include <QComboBox>
#include <QWidget>
#include <QModelIndex>
#include <QApplication>
#include <QString>

#include <iostream>

ComboBoxDelegate::ComboBoxDelegate(QObject *parent)
:QItemDelegate(parent)
{
Items.push_back("Test0");
Items.push_back("Test1");
Items.push_back("Test2");
Items.push_back("Test3");
Items.push_back("Test4");
Items.push_back("Test5");
Items.push_back("Test6");
Items.push_back("Test7");
Items.push_back("Test8");
}

QWidget *ComboBoxDelegate::createEditor(QWidget *parent, const QStyleOptionViewItem &/* option */, const QModelIndex &/* index */) const
{
QComboBox* editor = new QComboBox(parent);
for(unsigned int i = 0; i < Items.size(); ++i)
{
editor->addItem(Items[i].c_str());
}
return editor;
}

void ComboBoxDelegate::setEditorData(QWidget *editor, const QModelIndex &index) const
{
QComboBox *comboBox = static_cast<QComboBox*>(editor);
int value = index.model()->data(index, Qt::EditRole).toUInt();
comboBox->setCurrentIndex(value);
}

void ComboBoxDelegate::setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const
{
QComboBox *comboBox = static_cast<QComboBox*>(editor);
model->setData(index, comboBox->currentIndex(), Qt::EditRole);
}

void ComboBoxDelegate::updateEditorGeometry(QWidget *editor, const QStyleOptionViewItem &option, const QModelIndex &/* index */) const
{
editor->setGeometry(option.rect);
}

void ComboBoxDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
QStyleOptionViewItemV4 myOption = option;
QString text = Items[index.row()].c_str();

myOption.text = text;

QApplication::style()->drawControl(QStyle::CE_ItemViewItem, &myOption, painter);
}

</source>

==CMakeLists.txt==
<source lang="cmake">
cmake_minimum_required(VERSION 2.6)

PROJECT(ComboBoxDelegate)

FIND_PACKAGE(Qt4 REQUIRED)
INCLUDE(${QT_USE_FILE})

QT4_WRAP_CPP(MOCSrcs ComboBoxDelegate.h)

include_directories(${include_directories} ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})

ADD_EXECUTABLE(ComboBoxDelegate main.cpp
ComboBoxDelegate.cpp
${MOCSrcs}
)
TARGET_LINK_LIBRARIES(ComboBoxDelegate ${QT_LIBRARIES})

</source>

ProgrammingExamples - User contributions [en]

User talk:Nelson Barata

Talk:Qt/Delegates/ComboBoxDelegate

Qt/Delegates/ComboBoxDelegate