qt_loaders.py 文件源码

def has_binding_new(api):
    """Safely check for PyQt4/5, PySide or PySide2, without importing submodules

    Supports Python >= 3.4

        Parameters
        ----------
        api : str [ 'pyqtv1' | 'pyqt' | 'pyqt5' | 'pyside' | 'pyside2' | 'pyqtdefault']
             Which module to check for

        Returns
        -------
        True if the relevant module appears to be importable
     """
    module_name = api_to_module[api]
    from importlib.util import find_spec

    required = ['QtCore', 'QtGui', 'QtSvg']
    if api in (QT_API_PYQT5, QT_API_PYSIDE2):
        # QT5 requires QtWidgets too
        required.append('QtWidgets')

    for submod in required:
        try:
            spec = find_spec('%s.%s' % (module_name, submod))
        except ImportError:
            # Package (e.g. PyQt5) not found
            return False
        else:
            if spec is None:
                # Submodule (e.g. PyQt5.QtCore) not found
                return False

    if api == QT_API_PYSIDE:
        # We can also safely check PySide version
        import PySide
        return check_version(PySide.__version__, '1.0.3')

    return True