如何在 python pyqtgraph PlotWidget 中设置刻度标签

我正在尝试绘制每天几个小时的时间序列，每天之间没有空白时间。如果我使用 pg.GraphicsWindow，则效果很好。刻度标签为 9:00 10:00 ..17:00。如果我使用 pg.PlotWidget 或 pg.PlotWindow，Alt2 和 Alt3 则不起作用，但会显示范数 0.1 0.2 ..。代码运行并调用 TimeAxisItem 类，但 x 轴刻度标签不会更改。我有一个更大的程序，其中包含 Qt.QMainWindow() 和 QtGui.QGridLayout() ，它不接受 pg.GraphicsWindow() 。我错过了什么？？如何在 PlotWidget 中设置刻度标签？

# -*- coding: utf-8 -*-
''' Setting x-axis labels for time series 
'''

import datetime as dt
from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg

class TimeAxisItem(pg.AxisItem):
    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
        tr=np.arange('2016-06-10 09:00', '2016-06-10 18:00', dtype='datetime64[h]')        
        tnorm=(tr-tr[0])/(tr[-1]-tr[0])  #Map time to 0.0-1.0
        ttick=list()
        for i,t in enumerate(tr):
            tstr=np.datetime64(t).astype(dt.datetime)
            ttick.append(  (tnorm[i],  tstr.strftime("%H:%M"))  )   
        self.setTicks([ttick])

def main():
    app = QtGui.QApplication([])
    x=np.arange(0.0, 1.0, 0.02)
    y=np.sin(2*np.pi*x)

    #Alt 1
    win = pg.GraphicsWindow(title="Basic plotting")            
    plot=win.addPlot(title='Timed data', axisItems={'bottom': TimeAxisItem(orientation='bottom')})
    plot.plot(x,y)

    # Alt 2
    #win = pg.PlotWidget(title="Basic plotting")            
    #win.plot(title='Timed data', axisItems={'bottom': TimeAxisItem(orientation='bottom')})
    #win.plot(x,y)
    
    #Alt 3
    #win=pg.PlotWindow(title="Basic plotting")
    #win.plot(title='Timed data', axisItems={'bottom': TimeAxisItem(orientation='bottom')})
    #win.plot(x,y)

    win.show()
    app.exec_()

if __name__ == '__main__':
    main()

# -*- coding: utf-8 -*-
''' Setting x-axis labels for time series 
Window, pyqtgraph (09.10) numpy (1.11.1) PyQt4(4.11.4)
'''

import datetime as dt
from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import pyqtgraph as pg

def main():
    app = QtGui.QApplication([])
    #Plot some data for 2 days
    x=np.arange(0.0, 1.0, 0.02)
    day0=100*np.sin(2*np.pi*x)   # Just som data to plot
    day1=100*(np.cos(2*np.pi*x)-1)   # Just som data to plot
    xx=np.concatenate([x,x+1]) # two days
    yy=np.concatenate([day0,day1])
    
    win = pg.PlotWidget(title="Plotting time series")            
    win.resize(1600,400)    
    win.plot(xx,yy)

    # Tick labels
    # tick labels one day        
    tr=np.arange('2016-06-10 09:00', '2016-06-10 18:00', dtype='datetime64[2h]')  
    tday0=(tr-tr[0])/(tr[-1]-tr[0])  #Map time to 0.0-1.0 day 2 1.0-2.0 ...
    tday1=tday0+1
    tnorm=np.concatenate([tday0,tday1])
    tr[-1]=tr[0]  # End day=start next day
    # Create tick labels for axis.setTicks
    ttick=list()    
    for i,t in enumerate(np.concatenate([tr,tr])):
        tstr=np.datetime64(t).astype(dt.datetime)
        ttick.append(  (tnorm[i],  tstr.strftime("%H:%M")))  

    ax=win.getAxis('bottom')    #This is the trick  
    ax.setTicks([ttick])

    # Set grid x and y-axis
    ax.setGrid(255)
    ay=win.getAxis('left')
    ay.setGrid(255)

    win.show()
    app.exec_()

if __name__ == '__main__':
    main()