Alternatives to QWindow::showNormal() for Window Management in Qt

Functionality

• It then makes the window visible by calling setVisible(true).
• It removes any flags indicating a maximized or minimized state. This is achieved by calling setWindowStates(Qt::WindowNoState).

Essentially, it transitions the window from a minimized, maximized, or hidden state to a regular viewable window.

Points to Consider

• This function works in conjunction with setVisible(true). Calling showNormal() alone wouldn't make the window visible if it's already hidden but not minimized or maximized.
• QWindow::showNormal() doesn't control the window size or position. You might need to set those using setGeometry() or resize() before calling showNormal().

• It's also useful for restoring a window to its normal state after it was minimized or maximized by the user.
• You can use showNormal() in your application's main window creation code to display it initially.

---

#include <QApplication>
#include <QPushButton>

class MainWindow : public QWidget {
  Q_OBJECT

public:
  explicit MainWindow(QWidget *parent = nullptr) : QWidget(parent) {
    QPushButton* button = new QPushButton("Click Me!", this);
    button->setGeometry(50, 50, 100, 30);

    // Set a preferred size for the window
    setFixedSize(300, 200);

    // Center the window on the screen
    centerWindow();
  }

private:
  void centerWindow() {
    // Get screen geometry information
    QDesktopWidget* desktop = QApplication::desktop();
    QRect screenRect = desktop->screenGeometry(this);
    QRect windowRect = geometry();

    // Calculate centered position
    int xPos = (screenRect.width() - windowRect.width()) / 2;
    int yPos = (screenRect.height() - windowRect.height()) / 2;

    // Move the window to the center
    move(xPos, yPos);
  }
};

int main(int argc, char *argv[]) {
  QApplication app(argc, argv);
  MainWindow window;

  // Show the window in normal state
  window.showNormal();

  return app.exec();
}

1. We define a MainWindow class that inherits from QWidget.
2. In the constructor, we create a button and set its geometry.
3. We set a preferred size for the window using setFixedSize().
4. The centerWindow() function retrieves the screen geometry and calculates the centered position for the window.
5. In the main function, we create an instance of QApplication and MainWindow.
6. Finally, we call showNormal() on the window object to display it in its normal state.

---

Using show()

• Use this if you want more control over the window's appearance (maximized, minimized, or normal) and handle those states separately.
• If the window was previously minimized or maximized, calling show() will bring it back but maintain that state.
• This function simply makes the window visible. It doesn't affect the maximized/minimized state.

Example

window.show(); // Makes the window visible, keeps its previous state

Combining setVisible(true) and Window Flags

• This allows you to define the initial appearance (e.g., with borders or not) independent of the maximized/minimized state.
• Use setWindowFlags with specific flags like Qt::WindowType::FrameWindow (for a normal window with borders) or Qt::WindowType::SubWindow (for a child window).
• Set setVisible(true) to make the window visible.
• This approach offers more granular control.

Example

window.setVisible(true);
window.setWindowFlags(Qt::WindowType::FrameWindow); // Set window type with borders

Using Platform-Specific Functions

• However, be cautious with these as they might not be portable across different platforms.
• For example, on Windows, you can use showMaximized() or showMinimized() for those functionalities.
• Qt provides some platform-specific functions to achieve specific window states.

• QWindow::showNormal() is a convenient option for a standard un-maximized/un-minimized view, but the alternatives offer more flexibility.
• Choose the approach that best suits your application's needs and desired window behavior.