Completer Example

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

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

    QWidget *centralWidget = new QWidget;

    QLabel *modelLabel = new QLabel;
    modelLabel->setText(tr("Model"));

    modelCombo = new QComboBox;
    modelCombo->addItem(tr("QFileSytemModel"));
    modelCombo->addItem(tr("QFileSytemModel that shows full path"));
    modelCombo->addItem(tr("Country list"));
    modelCombo->addItem(tr("Word list"));
    modelCombo->setCurrentIndex(0);

    QLabel *modeLabel = new QLabel;
    modeLabel->setText(tr("Completion Mode"));
    modeCombo = new QComboBox;
    modeCombo->addItem(tr("Inline"));
    modeCombo->addItem(tr("Filtered Popup"));
    modeCombo->addItem(tr("Unfiltered Popup"));
    modeCombo->setCurrentIndex(1);

    QLabel *caseLabel = new QLabel;
    caseLabel->setText(tr("Case Sensitivity"));
    caseCombo = new QComboBox;
    caseCombo->addItem(tr("Case Insensitive"));
    caseCombo->addItem(tr("Case Sensitive"));
    caseCombo->setCurrentIndex(0);

    QLabel *maxVisibleLabel = new QLabel;
    maxVisibleLabel->setText(tr("Max Visible Items"));
    maxVisibleSpinBox = new QSpinBox;
    maxVisibleSpinBox->setRange(3,25);
    maxVisibleSpinBox->setValue(10);

    wrapCheckBox = new QCheckBox;
    wrapCheckBox->setText(tr("Wrap around completions"));
    wrapCheckBox->setChecked(true);

    contentsLabel = new QLabel;
    contentsLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);

    connect(modelCombo, SIGNAL(activated(int)), this, SLOT(changeModel()));
    connect(modeCombo, SIGNAL(activated(int)), this, SLOT(changeMode(int)));
    connect(caseCombo, SIGNAL(activated(int)), this, SLOT(changeCase(int)));
    connect(maxVisibleSpinBox, SIGNAL(valueChanged(int)), this, SLOT(changeMaxVisible(int)));

    lineEdit = new QLineEdit;

    QGridLayout *layout = new QGridLayout;
    layout->addWidget(modelLabel, 0, 0); layout->addWidget(modelCombo, 0, 1);
    layout->addWidget(modeLabel, 1, 0);  layout->addWidget(modeCombo, 1, 1);
    layout->addWidget(caseLabel, 2, 0);  layout->addWidget(caseCombo, 2, 1);
    layout->addWidget(maxVisibleLabel, 3, 0); layout->addWidget(maxVisibleSpinBox, 3, 1);
    layout->addWidget(wrapCheckBox, 4, 0);
    layout->addWidget(contentsLabel, 5, 0, 1, 2);
    layout->addWidget(lineEdit, 6, 0, 1, 2);
    centralWidget->setLayout(layout);
    setCentralWidget(centralWidget);

    changeModel();

    setWindowTitle(tr("Completer"));
    lineEdit->setFocus();
}

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

    if (!fileName.contains(QLatin1String("countries.txt")))
        return new QStringListModel(words, completer);

    // The last two chars of the countries.txt file indicate the country
    // symbol. We put that in column 2 of a standard item model
    QStandardItemModel *m = new QStandardItemModel(words.count(), 2, completer);
    for (int i = 0; i < words.count(); ++i) {
        QModelIndex countryIdx = m->index(i, 0);
        QModelIndex symbolIdx = m->index(i, 1);
        QString country = words[i].mid(0, words[i].length() - 2).trimmed();
        QString symbol = words[i].right(2);
        m->setData(countryIdx, country);
        m->setData(symbolIdx, symbol);
    }

    return m;
}

void MainWindow::changeMode(int index)
{
    QCompleter::CompletionMode mode;
    if (index == 0)
        mode = QCompleter::InlineCompletion;
    else if (index == 1)
        mode = QCompleter::PopupCompletion;
    else
        mode = QCompleter::UnfilteredPopupCompletion;

    completer->setCompletionMode(mode);
}

void MainWindow::changeCase(int cs)
{
    completer->setCaseSensitivity(cs ? Qt::CaseSensitive : Qt::CaseInsensitive);
}

void MainWindow::changeModel()
{
    delete completer;
    completer = new QCompleter(this);
    completer->setMaxVisibleItems(maxVisibleSpinBox->value());

    switch (modelCombo->currentIndex()) {
    default:
    case 0:
        { // Unsorted QFileSystemModel
            QFileSystemModel *fsModel = new QFileSystemModel(completer);
            fsModel->setRootPath("");
            completer->setModel(fsModel);
            contentsLabel->setText(tr("Enter file path"));
        }
        break;
    case 1:
        {   // FileSystemModel that shows full paths
            FileSystemModel *fsModel = new FileSystemModel(completer);
            completer->setModel(fsModel);
            fsModel->setRootPath("");
            contentsLabel->setText(tr("Enter file path"));
        }
        break;
    case 2:
        { // Country List
            completer->setModel(modelFromFile(":/resources/countries.txt"));
            QTreeView *treeView = new QTreeView;
            completer->setPopup(treeView);
            treeView->setRootIsDecorated(false);
            treeView->header()->hide();
            treeView->header()->setStretchLastSection(false);
            treeView->header()->setSectionResizeMode(0, QHeaderView::Stretch);
            treeView->header()->setSectionResizeMode(1, QHeaderView::ResizeToContents);
            contentsLabel->setText(tr("Enter name of your country"));
        }
        break;
    case 3:
        { // Word list
            completer->setModel(modelFromFile(":/resources/wordlist.txt"));
            completer->setModelSorting(QCompleter::CaseInsensitivelySortedModel);
            contentsLabel->setText(tr("Enter a word"));
        }
        break;
    }

    changeMode(modeCombo->currentIndex());
    changeCase(caseCombo->currentIndex());
    completer->setWrapAround(wrapCheckBox->isChecked());
    lineEdit->setCompleter(completer);
    connect(wrapCheckBox, SIGNAL(clicked(bool)), completer, SLOT(setWrapAround(bool)));
}

void MainWindow::changeMaxVisible(int max)
{
    completer->setMaxVisibleItems(max);
}

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