from PySide6.QtWidgets import QMessageBox

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from PySide6.QtWidgets import QFileDialog
from pathlib import Path

The filter string format is `"Description (*.ext *.ext2);;Description2 (*.ext3)"`.

from PySide6.QtWidgets import (
    QDialog, QDialogButtonBox, QFormLayout, QLineEdit, QVBoxLayout
)
from PySide6.QtCore import Qt

class AddPersonDialog(QDialog):
    def __init__(self, parent=None) -> None:
        super().__init__(parent)
        self.setWindowTitle("Add Person")
        self.setModal(True)
        self.setMinimumWidth(300)
        self._setup_ui()

    def _setup_ui(self) -> None:
        layout = QVBoxLayout(self)

        form = QFormLayout()
        self._name_edit = QLineEdit()
        self._name_edit.setPlaceholderText("Full name")
        self._email_edit = QLineEdit()
        self._email_edit.setPlaceholderText("email@example.com")
        form.addRow("Name:", self._name_edit)
        form.addRow("Email:", self._email_edit)
        layout.addLayout(form)

        # Standard OK / Cancel buttons
        buttons = QDialogButtonBox(
            QDialogButtonBox.StandardButton.Ok | QDialogButtonBox.StandardButton.Cancel
        )
        buttons.accepted.connect(self._on_accept)
        buttons.rejected.connect(self.reject)
        layout.addWidget(buttons)

    def _on_accept(self) -> None:
        if not self._name_edit.text().strip():
            QMessageBox.warning(self, "Validation", "Name is required.")
            return
        self.accept()   # closes dialog and returns QDialog.Accepted

    def name(self) -> str:
        return self._name_edit.text().strip()

    def email(self) -> str:
        return self._email_edit.text().strip()

Use `QDialogButtonBox` for standard buttons — it respects platform button order conventions (OK/Cancel vs Cancel/OK).

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For modeless dialogs, keep a reference to prevent garbage collection:
```python
self._settings_dialog = SettingsDialog(self)
self._settings_dialog.show()

class SettingsDialog(QDialog):
    settings_changed = Signal(dict)

    def __init__(self, settings: dict, parent=None) -> None:
        super().__init__(parent)
        self._original = dict(settings)
        self._current = dict(settings)
        self._setup_ui(settings)

    def _on_change(self) -> None:
        self._current["theme"] = self._theme_combo.currentText()
        self.settings_changed.emit(self._current)   # live preview

    def reject(self) -> None:
        self.settings_changed.emit(self._original)  # restore on cancel
        super().reject()