Custom Completer Example

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#include <QtWidgets>
#include "mainwindow.h"
#include "textedit.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), completer(0)
{
    createMenu();

    completingTextEdit = new TextEdit;
    completer = new QCompleter(this);
    completer->setModel(modelFromFile(":/resources/wordlist.txt"));
    completer->setModelSorting(QCompleter::CaseInsensitivelySortedModel);
    completer->setCaseSensitivity(Qt::CaseInsensitive);
    completer->setWrapAround(false);
    completingTextEdit->setCompleter(completer);

    setCentralWidget(completingTextEdit);
    resize(500, 300);
    setWindowTitle(tr("Completer"));
}

void MainWindow::createMenu()
{
    QAction *exitAction = new QAction(tr("Exit"), this);
    QAction *aboutAct = new QAction(tr("About"), this);
    QAction *aboutQtAct = new QAction(tr("About Qt"), this);

    connect(exitAction, SIGNAL(triggered()), qApp, SLOT(quit()));
    connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));
    connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));

    QMenu* fileMenu = menuBar()->addMenu(tr("File"));
    fileMenu->addAction(exitAction);

    QMenu* helpMenu = menuBar()->addMenu(tr("About"));
    helpMenu->addAction(aboutAct);
    helpMenu->addAction(aboutQtAct);
}

QAbstractItemModel *MainWindow::modelFromFile(const QString& fileName)
{
    QFile file(fileName);
    if (!file.open(QFile::ReadOnly))
        return new QStringListModel(completer);

#ifndef QT_NO_CURSOR
    QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
#endif
    QStringList words;

    while (!file.atEnd()) {
        QByteArray line = file.readLine();
        if (!line.isEmpty())
            words << line.trimmed();
    }

#ifndef QT_NO_CURSOR
    QApplication::restoreOverrideCursor();
#endif
    return new QStringListModel(words, completer);
}

void MainWindow::about()
{
    QMessageBox::about(this, tr("About"), tr("This example demonstrates the "
        "different features of the QCompleter class."));
}