Question

我在pyqtgraph中创建了以下图形。它可以正常运行并按应有的方式显示。

import numpy as np
import pyqtgraph as pg
import pyqtgraph.exporters

from pyqtgraph.Qt import QtCore, QtGui
import csv
import itertools
from datetime import datetime as dt


app = QtGui.QApplication([])


class TimeAxisItem(pg.AxisItem):
    def tickStrings(self, values, scale, spacing):
            return [dt.fromtimestamp(value) for value in values]


x_vals = [dt(2018, 7, 1, 13, 6, 38), dt(2018, 7, 1, 12, 46, 38), dt(2018, 7, 1, 12, 36, 38), dt(2018, 7, 1, 12, 26, 38), dt(2018, 7, 1, 12, 16, 38), dt(2018, 7, 1, 12, 6, 38), dt(2018, 7, 1, 11, 56, 38), dt(2018, 7, 1, 11, 46, 38), dt(2018, 7, 1, 11, 36, 38), dt(2018, 7, 1, 11, 26, 38), dt(2018, 7, 1, 10, 56, 38), dt(2018, 7, 1, 10, 46, 38), dt(2018, 7, 1, 10, 36, 38)]
y_vals =  [23.5, 20.8, 28.0, 28.1, 28.0, 27.8, 27.3, 27.2, 25.7, 24.7, 25.0, 25.0, 24.9]


date_axis = TimeAxisItem(orientation='bottom')
plt = pg.PlotWidget(axisItems = {'bottom': date_axis})

# set properties
plt.setLabel('left', 'Temperature', units='C')
plt.setWindowTitle('Temperature over time')

plt.plot(x=[x.timestamp() for x in x_vals], y=y_vals, symbol=None, pen='r', symbolPen='r')
plt.show()  



if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

但是，当我尝试从某个函数运行它时，它会闪烁然后消失，但pyqt仍在运行。

import numpy as np
import pyqtgraph as pg
import pyqtgraph.exporters

from pyqtgraph.Qt import QtCore, QtGui
import csv
import itertools
from datetime import datetime as dt


app = QtGui.QApplication([])


class TimeAxisItem(pg.AxisItem):
    def tickStrings(self, values, scale, spacing):
        return [dt.fromtimestamp(value) for value in values]

def Gshow():
    # app = QtGui.QApplication([])
    x_vals = [dt(2018, 7, 1, 13, 6, 38), dt(2018, 7, 1, 12, 46, 38), dt(2018, 7, 1, 12, 36, 38), dt(2018, 7, 1, 12, 26, 38), dt(2018, 7, 1, 12, 16, 38), dt(2018, 7, 1, 12, 6, 38), dt(2018, 7, 1, 11, 56, 38), dt(2018, 7, 1, 11, 46, 38), dt(2018, 7, 1, 11, 36, 38), dt(2018, 7, 1, 11, 26, 38), dt(2018, 7, 1, 10, 56, 38), dt(2018, 7, 1, 10, 46, 38), dt(2018, 7, 1, 10, 36, 38)]
    y_vals =  [23.5, 20.8, 28.0, 28.1, 28.0, 27.8, 27.3, 27.2, 25.7, 24.7, 25.0, 25.0, 24.9]

    date_axis = TimeAxisItem(orientation='bottom')

    plt = pg.PlotWidget(axisItems = {'bottom': date_axis})

    # set properties
    plt.setLabel('left', 'Temperature', units='C')
    plt.setWindowTitle('Temperature over time')

    plt.plot(x=[x.timestamp() for x in x_vals], y=y_vals, symbol=None, pen='r', symbolPen='r')
    plt.show()  

Gshow()


if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

如何在不崩溃的情况下从函数运行图形？

Answer 1

问题真的很简单，在函数内创建的变量仅存在，直到函数完成执行为止，在您的情况下，plt被未显示的内容消除了，解决方案是增加该数据的范围，一种形式这样做是将其返回并传递给范围更大的变量。

import numpy as np
import pyqtgraph as pg
import pyqtgraph.exporters

from pyqtgraph.Qt import QtCore, QtGui
import csv
import itertools
from datetime import datetime as dt


app = QtGui.QApplication([])


class TimeAxisItem(pg.AxisItem):
    def tickStrings(self, values, scale, spacing):
        return [dt.fromtimestamp(value) for value in values]

def Gshow():
    # app = QtGui.QApplication([])
    x_vals = [dt(2018, 7, 1, 13, 6, 38), dt(2018, 7, 1, 12, 46, 38), dt(2018, 7, 1, 12, 36, 38), dt(2018, 7, 1, 12, 26, 38), dt(2018, 7, 1, 12, 16, 38), dt(2018, 7, 1, 12, 6, 38), dt(2018, 7, 1, 11, 56, 38), dt(2018, 7, 1, 11, 46, 38), dt(2018, 7, 1, 11, 36, 38), dt(2018, 7, 1, 11, 26, 38), dt(2018, 7, 1, 10, 56, 38), dt(2018, 7, 1, 10, 46, 38), dt(2018, 7, 1, 10, 36, 38)]
    y_vals =  [23.5, 20.8, 28.0, 28.1, 28.0, 27.8, 27.3, 27.2, 25.7, 24.7, 25.0, 25.0, 24.9]

    date_axis = TimeAxisItem(orientation='bottom')

    plt = pg.PlotWidget(axisItems = {'bottom': date_axis})

    # set properties
    plt.setLabel('left', 'Temperature', units='C')
    plt.setWindowTitle('Temperature over time')

    plt.plot(x=[x.timestamp() for x in x_vals], y=y_vals, symbol=None, pen='r', symbolPen='r')
    plt.show()  

    return plt  # <----

var = Gshow() # <----


if __name__ == '__main__':
    import sys
    if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

Answer 2

在main（）内调用Gshow（）

从函数运行pyqtgraph

2 个答案: