LEAutoCompletion.h

@#ifndef LEAUTOCOMPLETION_H
#define LEAUTOCOMPLETION_H

#include <QWidget>
#include <QLineEdit>
#include <QListView>
#include <QModelIndex>

namespace Ui {
class LEAutoCompletion;
}

class LEAutoCompletion : public QWidget
{
Q_OBJECT

public:
explicit LEAutoCompletion(QWidget *parent = 0);
~LEAutoCompletion();

private:
Ui::LEAutoCompletion *ui;
QLineEdit *mLineEdit;
QListView *mView;

protected:
bool eventFilter(QObject *target, QEvent *event);

private slots:
void onTextChanged(const QString &text);
void completeText(const QModelIndex &);
void textModified();
};

#endif // LEAUTOCOMPLETION_H@

LEAutoCompletion.cpp

@#include "LEAutoCompletion.h"
#include "ui_LEAutoCompletion.h"
#include <QVBoxLayout>
#include <QStringListModel>
#include <QSortFilterProxyModel>
#include <QEvent>
#include <QKeyEvent>

LEAutoCompletion::LEAutoCompletion(QWidget *parent) :
QWidget(parent),
ui(new Ui::LEAutoCompletion)
{
ui->setupUi(this);
mLineEdit = new QLineEdit(this);

QVBoxLayout *layout = new QVBoxLayout(this);
layout->addWidget(mLineEdit);
setLayout(layout);

knownList = NULL;

setWindowTitle("Auto Completion");

QStringList  list;
list<< "America"<<"Arica"<<"Belgium"<<"Canada"<<"Denmark"<<"India"<<"France"<<"Australia";

QStringListModel *model = new QStringListModel(this);
model->setStringList(list);

QSortFilterProxyModel *filterModel = new QSortFilterProxyModel(this);
filterModel->setSourceModel(model);
filterModel->setFilterCaseSensitivity(Qt::CaseInsensitive);
filterModel->sort(0,Qt::AscendingOrder);

mView = new QListView(this);
mView->setModel(filterModel);
mView->setEditTriggers(QAbstractItemView::NoEditTriggers);
mView->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
mView->setSelectionBehavior(QAbstractItemView::SelectRows);
mView->setSelectionMode(QAbstractItemView::SingleSelection);
mView->setParent(0, Qt::ToolTip);
mView->setFocusPolicy(Qt::NoFocus);
mView->setFocusProxy(mLineEdit);

connect(mLineEdit, SIGNAL(textChanged(QString)) , filterModel , SLOT(setFilterWildcard(QString)));
connect(mLineEdit, SIGNAL(editingFinished()), this, SLOT(textModified()));
connect(mLineEdit, SIGNAL(textChanged(QString)), this, SLOT(onTextChanged(const QString &)));
connect(mView, SIGNAL(activated(const QModelIndex &)), this, SLOT(completeText(const QModelIndex &)));
connect(mView, SIGNAL(clicked(const QModelIndex &)), this, SLOT(completeText(const QModelIndex &)));
installEventFilter(this);

}

LEAutoCompletion::~LEAutoCompletion()
{
delete ui;
delete mView;
}

bool LEAutoCompletion::eventFilter(QObject *target, QEvent *event)
{
if(target == this)
{
if(event->type() == QEvent::Resize || event->type() == QEvent::Move)
{
int lineEditWidth = mLineEdit->width();
mView->setMinimumWidth(lineEditWidth);
mView->setMaximumWidth(lineEditWidth);
mView->setMaximumHeight(100);

        QPoint p(0, mLineEdit->height());
        int x = mLineEdit->mapToGlobal(p).x();
        int y = mLineEdit->mapToGlobal(p).y();
        mView->move(x, y);
    }
}
return QWidget::eventFilter(target, event);

}

void LEAutoCompletion::onTextChanged(const QString &text)
{
if(text.isEmpty())
{
mView->hide();
}
else
{
mView->show();
}
}

void LEAutoCompletion::completeText(const QModelIndex &index)
{
mLineEdit->setText(index.data().toString());
}

void LEAutoCompletion::textModified()
{
QString text = mLineEdit->text();
}
@

OUTPUT:

![IMG]http://i.imgur.com/Y4uKrOJ.png[/IMG](ListView Suggestion List)!

Image of List View not Closed after the Application is closed.

![IMG]http://i.imgur.com/JLEQRnO.png[/IMG](ListView not closed after application closed)!