matplotlib.widget无法在ipython笔记本中工作

我正在运行ipython notebook –pylab inline.

任何建议将非常感谢.

下面是一个绘制正弦波并添加下一个和上一个按钮的示例
据说会改变轴,但我没有交互性：

from matplotlib.widgets import Button

fig,ax = plt.subplots()
fig.subplots_adjust(bottom=0.2)

t = np.linspace(0,10,1000)
line,= plt.plot(t,np.sin(t),lw=2)

class Index:
    dt = 0
    def next(self,event):
        self.dt -= 1
        line.set_ydata(np.sin(t + self.dt))
        fig.canvas.draw()

    def prev(self,event):
        self.dt += 1
        line.set_ydata(np.sin(t + self.dt))
        fig.canvas.draw()

callback = Index()
axprev = plt.axes([0.7,0.05,0.1,0.075])
axnext = plt.axes([0.81,0.075])

bnext = Button(axnext,'>')
bnext.on_clicked(callback.next)

bprev = Button(axprev,'<')
bprev.on_clicked(callback.prev)