mainwindow.cpp Example File
^{tools/treemodelcompleter/mainwindow.cpp}

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 #include <QtGui>
 #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(const QModelIndex&)),
                      this, SLOT(highlight(const 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(const QString&)),
             completer, SLOT(setSeparator(const 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(const QString&)),
             this, SLOT(updateContentsLabel(const 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);

     QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
     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;
     }

     QApplication::restoreOverrideCursor();

     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(QString(tr("Type path from model above with items at each level separated by a '%1'")).arg(sep));
 }