pyqt将枚举值转换为键

时间:2012-11-23 17:45:49

标签: python qt pyqt pyqt4

是否可以将qt枚举值转换为其键?

例如,我想知道QPrinter.A4 = 0

从QPrinter类获得'A4'

提前谢谢

4 个答案:

答案 0 :(得分:3)

通常,您可以使用QMetaObject

执行此操作
m = QtGui.QFrame.staticMetaObject
m.enumerator(m.indexOfEnumerator('Shadow')).valueToKey(QtGui.QFrame.Sunken)
'Sunken'

然而,似乎QPrinter没有公开元对象,所以你必须通过在Python中遍历QPrinter的属性来做到这一点(幸运的是,PyQt枚举是{{1的子类},所以可以通过int)识别:

isinstance

答案 1 :(得分:2)

使用varsisinstance构建枚举的双向映射:

>>> from PyQt4.QtGui import QPrinter
>>> pagesizes = {}
>>> for key, value in vars(QPrinter).iteritems():
...     if isinstance(value, QPrinter.PageSize):
...         pagesizes[key] = value
...         pagesizes[value] = key
... 
>>> pagesizes['A4']
0
>>> pagesizes[QPrinter.A4]
'A4'
>>> pagesizes[0]
'A4'

<强>更新

似乎vars()不适用于所有版本的PyQt,但dir()可能会这样做。因此,更强大的解决方案可能是:

>>> pagesizes = {}
>>> for key in dir(QPrinter):
...     value = getattr(QPrinter, key)
...     if isinstance(value, QPrinter.PageSize):
...         pagesizes[key] = value
...         pagesizes[value] = key
... 

(注意:仅用 pyqt-4.10.3 / qt-4.8.5 pyqt-4.10 / qt-5.1.1 pyqt-进行测试5.1 / QT-5.1.1

答案 2 :(得分:1)

我根据ecatmur的回答实现了一个功能:

def qenum_key(base, value):
    """Convert a Qt Enum value to its key as a string.

    Args:
        base: The object the enum is in, e.g. QFrame.
        value: The value to get.

    Return:
        The key associated with the value as a string, or None.
    """
    klass = value.__class__
    try:
        idx = klass.staticMetaObject.indexOfEnumerator(klass.__name__)
    except AttributeError:
        idx = -1
    if idx != -1:
        return klass.staticMetaObject.enumerator(idx).valueToKey(value)
    else:
        for name, obj in vars(base).items():
            if isinstance(obj, klass) and obj == value:
                return name
        return None

这首先尝试通过QMetaObject获取值,如果失败或者没有元对象,则返回纯Python方法。

答案 3 :(得分:0)

此实现类似于 The Compiler's one,但找出基类 (QPrinter, QFrame 等)本身。

import sys


def enum_key(enum_val, with_val=False):
    """
    Return name of Qt enum value.
    `enum_val` - enum value
    `with_val` (bool) - return value as part of name
    """
    enum_cls = enum_val.__class__
    parent = sys.modules.get(enum_cls.__module__)
    for i in enum_cls.__qualname__.split(".")[:-1]:
        parent = getattr(parent, i)
    m = getattr(parent, "staticMetaObject", None)
    if m:
        idx = m.indexOfEnumerator(enum_cls.__name__)
        name = m.enumerator(idx).valueToKey(enum_val)
    else:
        for n, val in vars(parent).items():
            if isinstance(val, enum_cls) and val == enum_val:
                name = n
                break
    return "%s (%d)" % (name, enum_val) if with_val else name

# from PyQt5 import QtPrintSupport
# print(enum_key(QtPrintSupport.QPrinter.A5, with_val=1))
# >> A5 (9)