张宗平
1f66098277
p03/ 生成产物与 docs/teaching/examples/ 手工示例里的 QTimer::singleShot 自动退出逻辑，从"始终 200ms 后退出"改为"仅当 QT_QPA_PLATFORM=offscreen 时才退出"。正常运行（有显示环境）窗口保持打开，需手动关闭；离屏自动化 验证（tools/run_qt.sh + QT_QPA_PLATFORM=offscreen）行为不变。 p03/ 改动来自重新生成 tools/gen_part3.py（AUTO_QUIT 常量加 qgetenv 判断）， 未手改生成产物。QCoreApplication 控制台风格示例（qfile_basic 等）本就 执行完即退出，不受影响。
p03/ch09 — Qt 示例
可运行示例
| 目标 | 源文件 | 说明 |
|---|---|---|
mouse_event |
mouse_event.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh mouse_event |
event_override_customwidget |
event_override_customwidget.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh event_override_customwidget |
event_filter_mainwindow |
event_filter_mainwindow.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh event_filter_mainwindow |
参考片段（签名/伪代码，未单独建目标）
[block 1] .1 事件
label->setMouseTracking(true);
[block 3] .2 event（）
bool CustomTextEdit::event(QEvent *e)
{
if (e->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(e);
if (keyEvent->key() == Qt::Key_Tab)
{
qDebug() << "You press tab.";
return true;
}
}
return false;
}
[block 4] .2 event（）
switch (event->type()) {
case QEvent::MouseMove:
mouseMoveEvent((QMouseEvent*)event);
break;
// ...
}
[block 5] .2 event（）
//!!! Qt5
bool QObject::event(QEvent *e)
{
switch (e->type()) {
case QEvent::Timer:
timerEvent((QTimerEvent*)e);
break;
case QEvent::ChildAdded:
case QEvent::ChildPolished:
case QEvent::ChildRemoved:
childEvent((QChildEvent*)e);
break;
// ...
default:
if (e->type() >= QEvent::User) {
customEvent(e);
break;
}
return false;
}
return true;
}
[block 7] .3 事件过滤器
bool CustomWidget::event(QEvent *e)
{
if (e->type() == QEvent::KeyPress) {
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(e);
if (keyEvent->key() == Qt::Key_Tab) {
qDebug() << "You press tab.";
return true;
}
}
return QWidget::event(e);
}
现在，我们可以给出一个使用事件过滤器的版本：
bool FilterObject::eventFilter(QObject *object, QEvent *event)
{
if (object == target && event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if (keyEvent->key() == Qt::Key_Tab) {
qDebug() << "You press tab.";
return true;
} else {
return false;
}
}
return false;
}
[block 8] .4 总结
LRESULT CALLBACK WndProc(HWND hWnd,
UINT message,
WPARAM wParam,
LPARAM lParam)
[block 9] .4 总结
switch(message)
{
case WM_PAINT:
// ...
break;
case WM_DESTROY:
// ...
break;
...
}
[block 10] .4 总结
virtual bool QCoreApplication::notify ( QObject * receiver,
QEvent * event );