【Qt编程】自动补全功能

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include<QMouseEvent>

namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT
    
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    void mousePressEvent(QMouseEvent *event);
private:
    Ui::Widget *ui;
signals:
    void movesignal();
};

#endif // WIDGET_H

#ifndef COMPLETELINEEDIT_H
#define COMPLETELINEEDIT_H
#include <QLineEdit>
#include <QStringList>
#include<QFile>
#include<QTextCodec>
#include<QDebug>
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 slots:
    void replyMoveSignal();
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 "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
}

Widget::~Widget()
{
    delete ui;
}

void Widget::mousePressEvent(QMouseEvent *event)
{
    emit movesignal();
}

#include "CompleteLineEdit.h"
#include <QKeyEvent>
#include <QListView>
#include <QStringListModel>
#include <QDebug>
CompleteLineEdit::CompleteLineEdit(QStringList words, QWidget *parent)
    : QLineEdit(parent), words(words)
{
    listView = new QListView(this);//用于显示下拉列表
    model = new QStringListModel(this);
    listView->setWindowFlags(Qt::ToolTip);//设置下拉列表的样式
    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();//当输入行不是焦点时，隐藏自动补全的下拉列表
}


void CompleteLineEdit::replyMoveSignal()
{
    listView->hide();//当输入行不是焦点时，隐藏自动补全的下拉列表
}


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
            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
            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())//没有输入内容的情况
    {
        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)
    {
        //填充模式一
        if (word.contains(text))//只要包含该输入内容就显示，这里也可以设置大小写不敏感
        {
            sl << word;
        }
        //填充模式二
//        if(word.indexOf(text,0,Qt::CaseInsensitive)==0)//必需与句首内容相同
//            sl<<word;
    }
    model->setStringList(sl);
    listView->setModel(model);
    if (model->rowCount() == 0)
    {
        return;
    }
    // 设置列表的显示位置及大小
    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();
}