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

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 #include <QtGui>
 #include "dirmodel.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("QDirModel"));
     modelCombo->addItem(tr("QDirModel 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);

     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)));

     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(wrapCheckBox, 3, 0);
     layout->addWidget(contentsLabel, 4, 0, 1, 2);
     layout->addWidget(lineEdit, 5, 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);

     QApplication::setOverrideCursor(QCursor(Qt::WaitCursor));
     QStringList words;

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

     QApplication::restoreOverrideCursor();

     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);

     switch (modelCombo->currentIndex()) {
     default:
     case 0:
         { // Unsorted QDirModel
             QDirModel *dirModel = new QDirModel(completer);
             completer->setModel(dirModel);
             contentsLabel->setText(tr("Enter file path"));
         }
         break;
     case 1:
         { // DirModel that shows full paths
             DirModel *dirModel = new DirModel(completer);
             completer->setModel(dirModel);
             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()->setResizeMode(0, QHeaderView::Stretch);
             treeView->header()->setResizeMode(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::about()
 {
     QMessageBox::about(this, tr("About"), tr("This example demonstrates the "
         "different features of the QCompleter class."));
 }