QT里关于eventFilter例子为何不能执行，请指教

[jianmuyan]

用的qt4.8,qt creater2.4.1
源码如下:
#include <QMainWindow>

class MainWindow : public QMainWindow
{
public:
MainWindow();

protected:
bool eventFilter(QObject *obj, QEvent *ev);

private:
QTextEdit *textEdit;
};

MainWindow::MainWindow()
{
textEdit = new QTextEdit;
setCentralWidget(textEdit);

textEdit->installEventFilter(this);
}

bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if (obj == textEdit) {
if (event->type() == QEvent::KeyPress) {
QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
qDebug() << "Ate key press" << keyEvent->key();
return true;
} else {
return false;
}
} else {
// pass the event on to the parent class
return QMainWindow::eventFilter(obj, event);
}
}

[xiachm]

什么叫不能执行？是编译不过？还是运行出错？还是执行结果不对？

[jianmuyan]

[Quote=引用 1 楼 xiachm 的回复:]

什么叫不能执行？是编译不过？还是运行出错？还是执行结果不对？
[/Quote]我例子里的源码如下：
在自己的MainWindow里重载了
protected:
bool eventFilter(QObject *obj, QEvent *event);

在cpp里添加
bool MainWindow::eventFilter(QObject *obj, QEvent *event)
{
if (obj == msgLabel)
{
if(event->type() ==QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent*>(event);
qDebug() << keyEvent->key(); //<< keyEvent->key();
return true;
}
else
{
return false;
}
}
else
{
// pass the event on to the parent class
return QMainWindow::eventFilter(obj, event);
}
}
执行报错。
..\MyApp\mainwindow.cpp:157: error: invalid static_cast from type 'QEvent*' to type 'QKeyEvent*'
..\MyApp\mainwindow.cpp:158: error: invalid use of incomplete type 'struct QKeyEvent'
..\..\4.8.0\include/QtGui/../../src/gui/kernel/qwidget.h:83: error: forward declaration of 'struct QKeyEvent'

[jdwx]

#include <QKeyEvent>

[xiachm]

[Quote=引用 3 楼 jdwx1 的回复:]

#include <QKeyEvent>
[/Quote]
+1

另外看楼主的代码里还有qDebug()，还得#include <QDebug>

[jianmuyan]

汗。犯了低级错误了。

谢谢楼上两位。结贴