Qt开发新手咨询：哪些类应当继承QMainWindow？

Hey there! As someone new to Qt development (especially in VS with C++), it makes total sense to want clarity on when to use QMainWindow vs other widget classes. Let's break this down specifically for your single-UI, multi-subproject setup:

Cases Where You Should Inherit QMainWindow #

• Your application's primary main window
  This is the most obvious use case. QMainWindow is designed explicitly to be the top-level container for your app's core UI—it comes with built-in support for menus, toolbars, status bars, dock widgets, and a central widget area. For your single-UI project, this will be the main (and likely only) top-level window that houses all your subproject's functionality.
• Standalone top-level windows that require main window features
  If you have a separate window that needs its own menus, toolbars, or dockable panels (and it's not just a temporary popup), you might opt for another QMainWindow. That said, since you're targeting a single UI, this scenario should be rare—think carefully if this window can't be integrated into your main window instead (e.g., as a dock widget or a tab in a stacked widget).

Cases Where You Shouldn't Inherit QMainWindow #

• Temporary dialogs or popups
  For one-off interactions (like settings panels, confirmation prompts, or input forms), use QDialog or its specialized subclasses (e.g., QMessageBox, QInputDialog). These are designed for modal/non-modal temporary windows and don't need the full main window framework.
• Embedded UI components
  Any widget that lives inside your main window (like a feature-specific panel, a custom form, or a data visualization) should inherit QWidget (or a more specific widget class like QFrame, QStackedWidget). You can then add these as your main window's central widget, or place them in dock areas.
• Reusable UI modules
  If you're building a component that needs to be used across multiple parts of your project (or even other projects), stick to QWidget or a relevant control subclass. This keeps the component flexible enough to embed anywhere, rather than tying it to the main window structure.

For Your Specific Setup #

Since you mentioned your project uses a single UI but currently has two QMainWindow subclasses, take a minute to evaluate the second one:

• Does it really need menus, toolbars, or dock widgets? If not, convert it to a QWidget or QDialog and integrate it into your main window.
• Is it meant to be a secondary top-level window? If so, ask yourself if this aligns with your "single UI" goal—users often find multiple top-level main windows confusing.

Remember, Qt's design encourages using QMainWindow as the core container for your app's main interface, and using lighter widgets/dialogs for all other UI elements. This keeps your codebase clean and your user experience consistent.

内容的提问来源于stack exchange，提问作者skm