- Qt 5.5
- Qt Widgets
- Completer Example
- mainwindow.cpp Example File
- Qt 5.5.1 Reference Documentation

# mainwindow.cpp Example File

tools/completer/mainwindow.cpp

    /****************************************************************************
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    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** This file is part of the examples of the Qt Toolkit.
    **
    ** $QT_BEGIN_LICENSE:BSD$
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    **     contributors may be used to endorse or promote products derived
    **     from this software without specific prior written permission.
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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."));
    }