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/ch06 — Qt 示例
可运行示例
| 目标 | 源文件 | 说明 |
|---|---|---|
modal_dialog |
modal_dialog.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh modal_dialog |
modeless_dialog_stack |
modeless_dialog_stack.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh modeless_dialog_stack |
modeless_dialog_heap |
modeless_dialog_heap.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh modeless_dialog_heap |
modeless_dialog_deleteonclose |
modeless_dialog_deleteonclose.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh modeless_dialog_deleteonclose |
message_box_question |
message_box_question.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh message_box_question |
message_box_custom |
message_box_custom.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh message_box_custom |
file_dialog |
file_dialog.cpp |
构建运行见顶层 README；离屏验证 QT_QPA_PLATFORM=offscreen tools/run_qt.sh file_dialog |
参考片段（签名/伪代码，未单独建目标）
[block 4] .4 消息对话框
void about(QWidget * parent, const QString & title, const QString & text)
[block 5] .4 消息对话框
void aboutQt(QWidget * parent, const QString & title = QString())：
[block 6] .4 消息对话框
StandardButton critical(QWidget * parent,
const QString & title,
const QString & text,
StandardButtons buttons = Ok,
StandardButton defaultButton = NoButton)：
[block 7] .4 消息对话框
StandardButton information(QWidget * parent,
const QString & title,
const QString & text,
StandardButtons buttons = Ok,
StandardButton defaultButton = NoButton)
[block 8] .4 消息对话框
StandardButton question(QWidget * parent,
const QString & title,
const QString & text,
StandardButtons buttons = StandardButtons( Yes | No ),
StandardButton defaultButton = NoButton)
[block 9] .4 消息对话框
StandardButton warning(QWidget * parent,
const QString & title,
const QString & text,
StandardButtons buttons = Ok,
StandardButton defaultButton = NoButton)
[block 13] 6.5 标准文件对话框
connect(openAction, &QAction::triggered,
this, &MainWindow::openFile);
connect(saveAction, &QAction::triggered,
this, &MainWindow::saveFile);
[block 14] 6.5 标准文件对话框
//打开文件
void MainWindow::openFile()
{
QString path = QFileDialog::getOpenFileName(this,
tr("Open File"), ".", tr("Text Files(*.txt)"));
if(!path.isEmpty())
{
QFile file(path);
if (!file.open(QIODevice::ReadOnly | QIODevice::Text))
{
QMessageBox::warning(this, tr("Read File"),
tr("Cannot open file:\n%1").arg(path));
return;
}
QTextStream in(&file);
textEdit->setText(in.readAll());
file.close();
}
else
{
QMessageBox::warning(this, tr("Path"),
tr("You did not select any file."));
}
}
//保存文件
void MainWindow::saveFile()
{
QString path = QFileDialog::getSaveFileName(this,
tr("Open File"), ".", tr("Text Files(*.txt)"));
if(!path.isEmpty())
{
QFile file(path);
if (!file.open(QIODevice::WriteOnly | QIODevice::Text))
{
QMessageBox::warning(this, tr("Write File"),
tr("Cannot open file:\n%1").arg(path));
return;
}
QTextStream out(&file);
out << textEdit->toPlainText();
file.close();
}
else
{
QMessageBox::warning(this, tr("Path"),
tr("You did not select any file."));
}
}
[block 15] 6.5 标准文件对话框
QString getOpenFileName(QWidget * parent = 0,
const QString & caption = QString(),
const QString & dir = QString(),
const QString & filter = QString(),
QString * selectedFilter = 0,
Options options = 0)