QlineEdit下拉列表设置及无文字时鼠标点击显示所有下拉数据

1.增加如下设置

completer->setCaseSensitivity(Qt::CaseInsensitive);
completer->setCompletionMode(QCompleter::UnfilteredPopupCompletion);
lineEdit->completer()->complete();

这是你如何做到的：

为你的lineedit定义textChanged插槽;
覆盖窗口的customEvent方法;
在textChanged插槽中将用户事件发送到窗口
lineedit的文字长度为零;
在customEvent方法中,只要收到用户事件,就会显示完成;

以下是一个例子：

mainwindow.h：

1. class MainWindow : public QMainWindow

2. {

3. Q_OBJECT

4. public:

5. explicit MainWindow(QWidget *parent = 0);

6. ~MainWindow();

7. protected:

8. void customEvent(QEvent * event);

9. private:

10. Ui::MainWindow *ui;

11. private slots:

12. void on_lineEdit_textChanged(QString );

13. };

mainwindow.cpp：

1. class CompleteEvent : public QEvent

2. {

3. public:

4. CompleteEvent(QLineEdit *lineEdit) : QEvent(QEvent::User),m_lineEdit(lineEdit) { }

5. void complete()

6. {

7. m_lineEdit->completer()->complete();

8. }

9. private:

10. QLineEdit *m_lineEdit;

11. };

12. MainWindow::MainWindow(QWidget *parent) :

13. QMainWindow(parent),ui(new Ui::MainWindow)

14. {

15. ui->setupUi(this);

16. QStringList wordList;

17. wordList << "one" << "two" << "three" << "four";

18. QLineEdit *lineEdit = new QLineEdit(this);

19. lineEdit->setGeometry(20,20,200,30);

20. connect(lineEdit,SIGNAL(textChanged(QString)),SLOT(on_lineEdit_textChanged(QString )));

21. QCompleter *completer = new QCompleter(wordList,this);

22. completer->setCaseSensitivity(Qt::CaseInsensitive);

23. completer->setCompletionMode(QCompleter::UnfilteredPopupCompletion);

24. lineEdit->setCompleter(completer);

25. }

26. MainWindow::~MainWindow()

27. {

28. delete ui;

29. }

30. void MainWindow::customEvent(QEvent * event)

31. {

32. QMainWindow::customEvent(event);

33. if (event->type()==QEvent::User)

34. ((CompleteEvent*)event)->complete();

35. }

36. void MainWindow::on_lineEdit_textChanged(QString text)

37. {

38. if (text.length()==0)

39. QApplication::postEvent(this,new CompleteEvent((QLineEdit*)sender()));

40. }