1.环境

Microsoft Visual Studio 2008 + Qt4.8.6

2.UI

3.Qt按键事件——QKeyEvent

QKeyEvent是一个描述Qt键盘事件的类。当有按键按下或者松开的时候，按键事件key event将会发送消息给QWidget。Key Event包含一个特殊的接收标记，标记接收者是否处理该按键事件。由于Jungle想标记按下的是哪个键，因此需要重载按键事件处理函数keyPressEvent。

另一方面，键盘上的每个键，都作为Qt的一个枚举成员，如下图（来源：Qt官方文档）

因此，可以在按键事件处理函数keyPressEvent中识别并在界面上打印出具体的按键。

4.实现

建立一个QKeyBoard的Qt Widget工程，在头文件中声明两个函数：

1 void keyPressEvent(QKeyEvent *event); 2 void keyReleaseEvent(QKeyEvent *event);

源文件中实现如下：

 1 void QKeyBoard::keyPressEvent(QKeyEvent *event){  2     switch(event->key()){  3         case Qt::Key_Escape:  4             this->ui.textEdit_press->append("Key_Escape Press");  5             break;  6         case Qt::Key_Tab:  7             this->ui.textEdit_press->append("Key_Tab Press");  8             break;  9         case Qt::Key_Enter: 10             this->ui.textEdit_press->append("Key_Enter Press"); 11             break; 12         case Qt::Key_Delete: 13             this->ui.textEdit_press->append("Key_Delete Press"); 14             break; 15         case Qt::Key_Space: 16             this->ui.textEdit_press->append("Key_Space Press"); 17             break; 18         case Qt::Key_Left: 19             this->ui.textEdit_press->append("Key_Left Press"); 20             break; 21         case Qt::Key_Up: 22             this->ui.textEdit_press->append("Key_Up Press"); 23             break; 24         case Qt::Key_Right: 25             this->ui.textEdit_press->append("Key_Right Press"); 26             break; 27         case Qt::Key_Down: 28             this->ui.textEdit_press->append("Key_Down Press"); 29             break; 30         /*default: 31  this->ui.textEdit->append("KeyEvent");*/
32  } 33 } 34  
35 void QKeyBoard::keyReleaseEvent(QKeyEvent *event){ 36     switch(event->key()){ 37         case Qt::Key_Escape: 38             this->ui.textEdit_release->append("Key_Escape Release"); 39             break; 40         case Qt::Key_Tab: 41             this->ui.textEdit_release->append("Key_Tab Release"); 42             break; 43         case Qt::Key_Enter: 44             this->ui.textEdit_release->append("Key_Enter Release"); 45             break; 46         case Qt::Key_Delete: 47             this->ui.textEdit_release->append("Key_Delete Release"); 48             break; 49         case Qt::Key_Space: 50             this->ui.textEdit_release->append("Key_Space Release"); 51             break; 52         case Qt::Key_Left: 53             this->ui.textEdit_release->append("Key_Left Release"); 54             break; 55         case Qt::Key_Up: 56             this->ui.textEdit_release->append("Key_Up Release"); 57             break; 58         case Qt::Key_Right: 59             this->ui.textEdit_release->append("Key_Right Release"); 60             break; 61         case Qt::Key_Down: 62             this->ui.textEdit_release->append("Key_Down Release"); 63             break; 64             /*default: 65  this->ui.textEdit->append("KeyEvent");*/
66  } 67 }