pyqtgraph实时更新图不显示

Question

我尝试了以下代码，它在单个脚本文件中运行，我可以看到实时更新的图表，

from PyQt4 import QtGui, QtCore
import numpy as np
import pyqtgraph as pg
from pyqtgraph.ptime import time

app = QtGui.QApplication([])

pw = pg.plot()
timer = pg.QtCore.QTimer()


def update():
    x = np.random.normal(size=(100))
    y = np.random.normal(size=(100))
    pw.plot(x, y, clear=True)


timer.timeout.connect(update)
timer.start(0)

## Start Qt event loop unless running in interactive mode.
if __name__ == '__main__':
    import sys

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

但是，如果我将实时更新部分放入一个在对话框中单击按钮时调用的函数中，则图表不会显示任何内容，

class TestDialog(QtGui.QDialog):
    def __init__(self, parent):
        super(TestDialog, self).__init__(parent, flags=QtCore.Qt.WindowMinimizeButtonHint|QtCore.Qt.WindowMaximizeButtonHint)

    self.resize(1000,618)

    self.chart_button = QtGui.QPushButton('Show chart', self)
    self.chart_button.clicked.connect(self.show_chart)
    vbox = QtGui.QVBoxLayout()
    vbox.addwidget(self.chart_button)
    self.setLayout(vbox)

    def show_chart(self):
        pw = pg.plot()
        timer = pg.QtCore.QTimer()

        def update():
            x = np.random.normal(size=(100))
            y = np.random.normal(size=(100))
            pw.plot(x, y, clear=True)

        timer.timeout.connect(update)
        timer.start(0)
        if (sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
            QtGui.QApplication.instance().exec_()

如果我在 update 函数中设置断点，我发现它没有在第二个脚本中调用，请问为什么？

Answer 1

下面的代码对我有用：

# -*- coding: utf-8 -*-
from PyQt4 import QtGui, QtCore
import numpy as np
import pyqtgraph as pg
import sys
from pyqtgraph.ptime import time



class TestDialog(QtGui.QMainWindow):
    def __init__(self, parent):
        super(TestDialog, self).__init__()
        self.parent=parent
        self.centralWidget = QtGui.QWidget()
        self.setCentralWidget(self.centralWidget)
        self.resize(1000,618)
        self.vbox = QtGui.QVBoxLayout()

        self.chart_button = QtGui.QPushButton('Show chart', self)
        self.pw = pg.PlotWidget()
        self.vbox.addWidget(self.chart_button)
        self.vbox.addWidget(self.pw)
        self.centralWidget.setLayout(self.vbox)
        x = np.random.normal(size=(100))
        y = np.random.normal(size=(100))
        self.pw.plot(x, y,clear=True)
        self.chart_button.clicked.connect(self.show_chart)


    def update(self): 
        x = np.random.normal(size=(100))
        y = np.random.normal(size=(100))
        self.pw.plot(x, y, clear=True)
        QtCore.QCoreApplication.processEvents()


    def show_chart(self):
        self.timer = pg.QtCore.QTimer()
        self.timer.setSingleShot(False)
        self.timer.timeout.connect(self.update)
        self.timer.start(100)




## Start Qt event loop unless running in interactive mode.
def main():
    app = QtGui.QApplication(sys.argv)
    ex = TestDialog(app)
    ex.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()

如果需要，您也可以将更新保留在 show_chart 函数中。

def show_chart(self):
    def update( ):
        x = np.random.normal(size=(100))
        y = np.random.normal(size=(100))
        self.pw.plot(x, y, clear=True)
        QtCore.QCoreApplication.processEvents()
    self.update = update
    self.timer = pg.QtCore.QTimer()
    self.timer.setSingleShot(False)
    self.timer.timeout.connect(self.update)
    self.timer.start(100)

Answer 2

您只需将父项传递给计时器即可。更改

timer = pg.QtCore.QTimer()

至

timer = pg.QtCore.QTimer(self)

pyqtgraph实时更新图不显示

pyqtgraph real time updating graph not showing

python

pyqt

pyqt4

pyqtgraph