#ifndef COMPLETELINEEDIT_H

#define COMPLETELINEEDIT_H

#include <QtGui/QLineEdit>

#include <QStringList>

class QListView;

class QStringListModel;

class QModelIndex;

class CompleteLineEdit : public QLineEdit {

    Q_OBJECT

public:

    CompleteLineEdit(QStringList words, QWidget *parent = 0);

public slots:

    void setCompleter(const QString &text); // 动态的显示完成列表

    void completeText(const QModelIndex &index); // 点击完成列表中的项，使用此项自动完成输入的单词

protected:

    virtual void keyPressEvent(QKeyEvent *e);

    virtual void focusOutEvent(QFocusEvent *e);

private:

    QStringList words; // 整个完成列表的单词

    QListView *listView; // 完成列表

    QStringListModel *model; // 完成列表的model

};

#endif // COMPLETELINEEDIT_H

#include "CompleteLineEdit.h"

#include <QKeyEvent>

#include <QtGui/QListView>

#include <QtGui/QStringListModel>

#include <QDebug>

CompleteLineEdit::CompleteLineEdit(QStringList words, QWidget *parent)

    : QLineEdit(parent), words(words) {

    listView = new QListView(this);

    model = new QStringListModel(this);

    listView->setWindowFlags(Qt::ToolTip);

    connect(this, SIGNAL(textChanged(const QString &)), this, SLOT(setCompleter(const QString &)));

    connect(listView, SIGNAL(clicked(const QModelIndex &)), this, SLOT(completeText(const QModelIndex &)));

}

void CompleteLineEdit::focusOutEvent(QFocusEvent *e) {

    //listView->hide();

}

void CompleteLineEdit::keyPressEvent(QKeyEvent *e) {

    if (!listView->isHidden()) {

        int key = e->key();

        int count = listView->model()->rowCount();

        QModelIndex currentIndex = listView->currentIndex();

        if (Qt::Key_Down == key) {

            // 按向下方向键时，移动光标选中下一个完成列表中的项

            int row = currentIndex.row() + 1;

            if (row >= count) {

                row = 0;

            }

            QModelIndex index = listView->model()->index(row, 0);

            listView->setCurrentIndex(index);

        } else if (Qt::Key_Up == key) {

            // 按向下方向键时，移动光标选中上一个完成列表中的项

            int row = currentIndex.row() - 1;

            if (row < 0) {

                row = count - 1;

            }

            QModelIndex index = listView->model()->index(row, 0);

            listView->setCurrentIndex(index);

        } else if (Qt::Key_Escape == key) {

            // 按下Esc键时，隐藏完成列表

            listView->hide();

        } else if (Qt::Key_Enter == key || Qt::Key_Return == key) {

            // 按下回车键时，使用完成列表中选中的项，并隐藏完成列表

            if (currentIndex.isValid()) {

                QString text = listView->currentIndex().data().toString();

                setText(text);

            }

            listView->hide();

        } else {

            // 其他情况，隐藏完成列表，并使用QLineEdit的键盘按下事件

            listView->hide();

            QLineEdit::keyPressEvent(e);

        }

    } else {

        QLineEdit::keyPressEvent(e);

    }

}

void CompleteLineEdit::setCompleter(const QString &text) {

    if (text.isEmpty()) {

        listView->hide();

        return;

    }

    if ((text.length() > 1) && (!listView->isHidden())) {

        return;

    }

    // 如果完整的完成列表中的某个单词包含输入的文本，则加入要显示的完成列表串中

    QStringList sl;

    foreach(QString word, words) {

        if (word.contains(text)) {

            sl << word;

        }

    }

    model->setStringList(sl);

    listView->setModel(model);

    if (model->rowCount() == 0) {

        return;

    }

    // Position the text edit

    listView->setMinimumWidth(width());

    listView->setMaximumWidth(width());

    QPoint p(0, height());

    int x = mapToGlobal(p).x();

    int y = mapToGlobal(p).y() + 1;

    listView->move(x, y);

    listView->show();

}

void CompleteLineEdit::completeText(const QModelIndex &index) {

    QString text = index.data().toString();

    setText(text);

    listView->hide();

}