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#include "textedit.h"

#include <QCompleter>

#include <QKeyEvent>

#include <QAbstractItemView>

#include <QtDebug>

#include <QApplication>

#include <QModelIndex>

#include <QAbstractItemModel>

#include <QScrollBar>

//! [0]

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));

}

//! [0]

//! [1]

TextEdit::~TextEdit()

{

}

//! [1]

//! [2]

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(const QString&)),

                     this, SLOT(insertCompletion(const QString&)));

}

//! [2]

//! [3]

QCompleter *TextEdit::completer() const

{

    return c;

}

//! [3]

//! [4]

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);

}

//! [4]

//! [5]

QString TextEdit::textUnderCursor() const

{

    QTextCursor tc = textCursor();

    tc.select(QTextCursor::WordUnderCursor);

    return tc.selectedText();

}

//! [5]

//! [6]

void TextEdit::focusInEvent(QFocusEvent *e)

{

    if (c)

        c->setWidget(this);

    QTextEdit::focusInEvent(e);

}

//! [6]

//! [7]

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) // dont process the shortcut when we have a completer

        QTextEdit::keyPressEvent(e);

//! [7]

//! [8]

    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!

}

//! [8]