Traitsui范围()带有滑块入口框的致命错误

Question

下面是使用滑块的Mayavi网站上的一些示例代码。尝试在滑块范围外放入致命错误的数字：

from numpy import arange, pi, cos, sin
from traits.api import HasTraits, Range, Instance, 
        on_trait_change
from traitsui.api import View, Item, Group
from mayavi.core.api import PipelineBase
from mayavi.core.ui.api import MayaviScene, SceneEditor, 
                MlabSceneModel

dphi = pi/1000.
phi = arange(0.0, 2*pi + 0.5*dphi, dphi, 'd')
def curve(n_mer, n_long):
    mu = phi*n_mer
    x = cos(mu) * (1 + cos(n_long * mu/n_mer)*0.5)
    y = sin(mu) * (1 + cos(n_long * mu/n_mer)*0.5)
    z = 0.5 * sin(n_long*mu/n_mer)
    t = sin(mu)
    return x, y, z, t

class MyModel(HasTraits):
    n_meridional    = Range(0, 30, 6, )#mode='spinner')
    n_longitudinal  = Range(0, 30, 11, )#mode='spinner')
    scene = Instance(MlabSceneModel, ())
    plot = Instance(PipelineBase)

    # When the scene is activated, or when the parameters are changed, we
    # update the plot.
    @on_trait_change('n_meridional,n_longitudinal,scene.activated')
    def update_plot(self):
        x, y, z, t = curve(self.n_meridional, self.n_longitudinal)
        if self.plot is None:
             self.plot = self.scene.mlab.plot3d(x, y, z, t,
                                tube_radius=0.025, colormap='Spectral')
        else:
            self.plot.mlab_source.set(x=x, y=y, z=z, scalars=t)

    # The layout of the dialog created
    view = View(Item('scene', editor=SceneEditor(scene_class=MayaviScene),
                     height=250, width=300, show_label=False),
                Group(
                        '_', 'n_meridional', 'n_longitudinal',
                     ),
                resizable=True,
                )
my_model = MyModel()
my_model.configure_traits()

如何改进此代码以禁止用户触发这种致命错误？我认为可以停用条目框(例如setDisabled(True)(可以工作或完全删除它的行 - 但我不确定如何在属性中实现它。

Answer 1

经过大量的反复试验，这似乎是默认的traitsui默认Range()模式中的错误，至少在Mac OS X的情况下(我正在运行High Sierra，10.13，.3(。

解决方案是将默认的 mode更改为外观和行为相同的，减去程序的情况：

n_meridional = Range(0, 30, 6, mode='slider')