textedit.cpp Example File

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  #include "textedit.h"
  #include <QCompleter>
  #include <QKeyEvent>
  #include <QAbstractItemView>
  #include <QtDebug>
  #include <QApplication>
  #include <QModelIndex>
  #include <QAbstractItemModel>
  #include <QScrollBar>

  TextEdit::TextEdit(QWidget *parent)
  : QTextEdit(parent), c(0)
  {
      setPlainText(tr("This TextEdit provides autocompletions for words that have more than"
                      " 3 characters. You can trigger autocompletion using ") +
                      QKeySequence("Ctrl+E").toString(QKeySequence::NativeText));
  }

  TextEdit::~TextEdit()
  {
  }

  void TextEdit::setCompleter(QCompleter *completer)
  {
      if (c)
          QObject::disconnect(c, 0, this, 0);

      c = completer;

      if (!c)
          return;

      c->setWidget(this);
      c->setCompletionMode(QCompleter::PopupCompletion);
      c->setCaseSensitivity(Qt::CaseInsensitive);
      QObject::connect(c, SIGNAL(activated(QString)),
                       this, SLOT(insertCompletion(QString)));
  }

  QCompleter *TextEdit::completer() const
  {
      return c;
  }

  void TextEdit::insertCompletion(const QString& completion)
  {
      if (c->widget() != this)
          return;
      QTextCursor tc = textCursor();
      int extra = completion.length() - c->completionPrefix().length();
      tc.movePosition(QTextCursor::Left);
      tc.movePosition(QTextCursor::EndOfWord);
      tc.insertText(completion.right(extra));
      setTextCursor(tc);
  }

  QString TextEdit::textUnderCursor() const
  {
      QTextCursor tc = textCursor();
      tc.select(QTextCursor::WordUnderCursor);
      return tc.selectedText();
  }

  void TextEdit::focusInEvent(QFocusEvent *e)
  {
      if (c)
          c->setWidget(this);
      QTextEdit::focusInEvent(e);
  }

  void TextEdit::keyPressEvent(QKeyEvent *e)
  {
      if (c && c->popup()->isVisible()) {
          // The following keys are forwarded by the completer to the widget
         switch (e->key()) {
         case Qt::Key_Enter:
         case Qt::Key_Return:
         case Qt::Key_Escape:
         case Qt::Key_Tab:
         case Qt::Key_Backtab:
              e->ignore();
              return; // let the completer do default behavior
         default:
             break;
         }
      }

      bool isShortcut = ((e->modifiers() & Qt::ControlModifier) && e->key() == Qt::Key_E); // CTRL+E
      if (!c || !isShortcut) // do not process the shortcut when we have a completer
          QTextEdit::keyPressEvent(e);

      const bool ctrlOrShift = e->modifiers() & (Qt::ControlModifier | Qt::ShiftModifier);
      if (!c || (ctrlOrShift && e->text().isEmpty()))
          return;

      static QString eow("~!@#$%^&*()_+{}|:\"<>?,./;'[]\\-="); // end of word
      bool hasModifier = (e->modifiers() != Qt::NoModifier) && !ctrlOrShift;
      QString completionPrefix = textUnderCursor();

      if (!isShortcut && (hasModifier || e->text().isEmpty()|| completionPrefix.length() < 3
                        || eow.contains(e->text().right(1)))) {
          c->popup()->hide();
          return;
      }

      if (completionPrefix != c->completionPrefix()) {
          c->setCompletionPrefix(completionPrefix);
          c->popup()->setCurrentIndex(c->completionModel()->index(0, 0));
      }
      QRect cr = cursorRect();
      cr.setWidth(c->popup()->sizeHintForColumn(0)
                  + c->popup()->verticalScrollBar()->sizeHint().width());
      c->complete(cr); // popup it up!
  }