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 }