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

# mainwindow.cpp Example File

tools/treemodelcompleter/mainwindow.cpp

    /****************************************************************************
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    ** This file is part of the examples of the Qt Toolkit.
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    #include <QtWidgets>
    #include "treemodelcompleter.h"
    #include "mainwindow.h"

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

        completer = new TreeModelCompleter(this);
        completer->setModel(modelFromFile(":/resources/treemodel.txt"));
        completer->setSeparator(QLatin1String("."));
        QObject::connect(completer, SIGNAL(highlighted(QModelIndex)),
                         this, SLOT(highlight(QModelIndex)));

        QWidget *centralWidget = new QWidget;

        QLabel *modelLabel = new QLabel;
        modelLabel->setText(tr("Tree Model<br>(Double click items to edit)"));

        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 *separatorLabel = new QLabel;
        separatorLabel->setText(tr("Tree Separator"));

        QLineEdit *separatorLineEdit = new QLineEdit;
        separatorLineEdit->setText(completer->separator());
        connect(separatorLineEdit, SIGNAL(textChanged(QString)),
                completer, SLOT(setSeparator(QString)));

        QCheckBox *wrapCheckBox = new QCheckBox;
        wrapCheckBox->setText(tr("Wrap around completions"));
        wrapCheckBox->setChecked(completer->wrapAround());
        connect(wrapCheckBox, SIGNAL(clicked(bool)), completer, SLOT(setWrapAround(bool)));

        contentsLabel = new QLabel;
        contentsLabel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
        connect(separatorLineEdit, SIGNAL(textChanged(QString)),
                this, SLOT(updateContentsLabel(QString)));

        treeView = new QTreeView;
        treeView->setModel(completer->model());
        treeView->header()->hide();
        treeView->expandAll();

        connect(modeCombo, SIGNAL(activated(int)), this, SLOT(changeMode(int)));
        connect(caseCombo, SIGNAL(activated(int)), this, SLOT(changeCase(int)));

        lineEdit = new QLineEdit;
        lineEdit->setCompleter(completer);

        QGridLayout *layout = new QGridLayout;
        layout->addWidget(modelLabel, 0, 0); layout->addWidget(treeView, 0, 1);
        layout->addWidget(modeLabel, 1, 0);  layout->addWidget(modeCombo, 1, 1);
        layout->addWidget(caseLabel, 2, 0);  layout->addWidget(caseCombo, 2, 1);
        layout->addWidget(separatorLabel, 3, 0); layout->addWidget(separatorLineEdit, 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);

        changeCase(caseCombo->currentIndex());
        changeMode(modeCombo->currentIndex());

        setWindowTitle(tr("Tree Model 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);
    }

    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);
    }

    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;

        QStandardItemModel *model = new QStandardItemModel(completer);
        QVector<QStandardItem *> parents(10);
        parents[0] = model->invisibleRootItem();

        while (!file.atEnd()) {
            QString line = file.readLine();
            QString trimmedLine = line.trimmed();
            if (line.isEmpty() || trimmedLine.isEmpty())
                continue;

            QRegExp re("^\\s+");
            int nonws = re.indexIn(line);
            int level = 0;
            if (nonws == -1) {
                level = 0;
            } else {
                if (line.startsWith("\t")) {
                    level = re.cap(0).length();
                } else {
                    level = re.cap(0).length()/4;
                }
            }

            if (level+1 >= parents.size())
                parents.resize(parents.size()*2);

            QStandardItem *item = new QStandardItem;
            item->setText(trimmedLine);
            parents[level]->appendRow(item);
            parents[level+1] = item;
        }

    #ifndef QT_NO_CURSOR
        QApplication::restoreOverrideCursor();
    #endif

        return model;
    }

    void MainWindow::highlight(const QModelIndex &index)
    {
        QAbstractItemModel *completionModel = completer->completionModel();
        QAbstractProxyModel *proxy = qobject_cast<QAbstractProxyModel *>(completionModel);
        if (!proxy)
            return;
        QModelIndex sourceIndex = proxy->mapToSource(index);
        treeView->selectionModel()->select(sourceIndex, QItemSelectionModel::ClearAndSelect | QItemSelectionModel::Rows);
        treeView->scrollTo(index);
    }

    void MainWindow::about()
    {
        QMessageBox::about(this, tr("About"), tr("This example demonstrates how "
            "to use a QCompleter with a custom tree model."));
    }

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

    void MainWindow::updateContentsLabel(const QString& sep)
    {
        contentsLabel->setText(tr("Type path from model above with items at each level separated by a '%1'").arg(sep));
    }