自动完成的QLineEdit(非使用QCompleter版)

来源：http://blog.csdn.net/starcloud_zxt/article/details/5186489

另一篇 http://hi.baidu.com/magictour/item/4be047cdd019482e46d5c0f8

-------------------------------------CompleteLineEdit.h-------------------------------------

 #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

-------------------------------------CompleteLineEdit.cpp-------------------------------------

 #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();
 }

-------------------------------------main.cpp----------------------------------

 #include <QtGui/QApplication>
 #include "CompleteLineEdit.h"
 #include <QtGui>
 #include <QCompleter>
 #include <QStringList>

 int main(int argc, char *argv[]) {
     QApplication a(argc, argv);
     QStringList sl = QStringList() << "Biao" << "Bin" << "Huang" << "Hua" << "Hello" << "BinBin" << "Hallo";
     QWidget widgetw;
     CompleteLineEdit * edit= new CompleteLineEdit(sl);
     QPushButton *button = new QPushButton("Button");
     QHBoxLayout *layout = new QHBoxLayout();
     layout->addWidget(edit);
     layout->addWidget(button);
     widgetw.setLayout(layout);
     widgetw.show();
     CompleteLineEdit e(sl);
     e.show();
     return a.exec();
 }