Python 动态更新QChart

我有一个类，它为给定的数据绘制一个烛台。我试图在收到新数据后立即动态更新绘图。数据以不规则的间隔接收

我可以使用什么机制让类知道是时候更新绘图了，并在使用新接收的数据点更新绘图时采取行动

类函数

append_data_和_plot（）

追加数据，但绘图永远不会更新。有人能解释一下问题是什么吗

import sys
from PyQt5.QtChart import QCandlestickSeries, QChart, QChartView, QCandlestickSet
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import Qt, QPointF
from PyQt5 import QtChart as qc
import time

class myCandlestick():
    def __init__(self, data):
        self.data = data
        self.app = QApplication(sys.argv)

        self.series = QCandlestickSeries()
        self.series.setDecreasingColor(Qt.red)
        self.series.setIncreasingColor(Qt.green)

        self.ma5 = qc.QLineSeries() 
        self.tm = []

        for num, o, h, l, c, m in self.data:
            self.series.append(QCandlestickSet(o, h, l, c))
            self.ma5.append(QPointF(num, m))
            self.tm.append(str(num))

        self.chart = QChart()

        self.chart.addSeries(self.series)  # candle
        self.chart.addSeries(self.ma5)  # ma5 line

        self.chart.createDefaultAxes()
        self.chart.legend().hide()

        self.chart.axisX(self.series).setCategories(self.tm)
        self.chart.axisX(self.ma5).setVisible(False)

        self.chartview = QChartView(self.chart)
        self.ui = QMainWindow()
        self.ui.setGeometry(50, 50, 500, 300)
        self.ui.setCentralWidget(self.chartview)
        self.ui.show()
        sys.exit(self.app.exec_())

    def append_data_and_plot(self, d):
        '''Append and update the plot'''
        num, o, h, l, c, m = d
        self.series.append(QCandlestickSet(o, h, l, c))
        self.ui.show()
        #sys.exit(self.app.exec_())


data = ((1, 7380, 7520, 7380, 7510, 7324),
        (2, 7520, 7580, 7410, 7440, 7372),
        (3, 7440, 7650, 7310, 7520, 7434),
        (4, 7450, 7640, 7450, 7550, 7480),
        (5, 7510, 7590, 7460, 7490, 7502),
        (6, 7500, 7590, 7480, 7560, 7512),
        (7, 7560, 7830, 7540, 7800, 7584))

m = myCandlestick(data)

# Data is received at irregular intervals
time.sleep(1)
m.append_data_and_plot((8, 7560, 7830, 7540, 7800, 7584))

# Data is received at irregular intervals
time.sleep(0.1)
m.append_data_and_plot((9, 7450, 7640, 7450, 7550, 7480))

# Data is received at irregular intervals
time.sleep(2.5)
m.append_data_and_plot((10, 7380, 7520, 7380, 7510, 7324))

---

Qt使用一个事件循环来处理gui的事件和任务，即代码“app.exec()（）”，因此该行之后的所有代码都不会被执行，如果添加到该行中，sys.exit（）将使应用程序在Qt事件循环结束时终止

解决方案是使用eventloop更新gui，例如使用QTimer：

import sys
from PyQt5.QtChart import QCandlestickSeries, QChart, QChartView, QCandlestickSet
from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import Qt, QPointF, QObject, pyqtSignal, QTimer
from PyQt5 import QtChart as qc

import random


class MainWindow(QMainWindow):
    def __init__(self, data, parent=None):
        super().__init__(parent)
        self.data = data

        self.series = QCandlestickSeries()
        self.series.setDecreasingColor(Qt.red)
        self.series.setIncreasingColor(Qt.green)

        self.ma5 = qc.QLineSeries()
        self.tm = []

        self.chart = QChart()

        self.chart.addSeries(self.series)  # candle
        self.chart.addSeries(self.ma5)  # ma5 line

        self.chart.createDefaultAxes()
        self.chart.legend().hide()

        self.chart.axisX(self.series).setCategories(self.tm)
        self.chart.axisX(self.ma5).setVisible(False)

        self.chartview = QChartView(self.chart)
        self.setGeometry(50, 50, 500, 300)
        self.setCentralWidget(self.chartview)

    def append_data_and_plot(self, d):
        """Append and update the plot"""
        num, o, h, l, c, m = d

        ax1 = self.chart.axisX(self.ma5)
        ay1 = self.chart.axisY(self.ma5)

        xmin = xmax = num
        ymin = ymax = m

        step = 10
        offset = 100

        for p in self.ma5.pointsVector()[-step:]:
            xmin = min(p.x(), xmin)
            xmax = max(p.x(), xmax)

            ymin = min(p.y(), ymin) - offset
            ymax = max(p.y(), ymax) + offset

        xmin = max(0, xmax - step)

        ax1.setMin(xmin)
        ax1.setMax(xmax)
        ay1.setMin(ymin)
        ay1.setMax(ymax)

        self.ma5.append(QPointF(num, m))
        self.tm.append(str(num))

        self.series.append(QCandlestickSet(o, h, l, c))
        ax2 = self.chart.axisX(self.series)
        ax2.setCategories(self.tm)
        ax2.setMin(str(xmin))
        ax2.setMax(str(xmax))

        ay2 = self.chart.axisY(self.series)
        ay2.setMin(ymin)
        ay2.setMax(ymax)


def create_data():


    i = 1
    while True:
        i += 1
        yield (
            i,
            random.randint(7000, 8000),
            random.randint(7000, 8000),
            random.randint(7000, 8000),
            random.randint(7000, 8000),
            random.randint(7000, 8000),
        )


class Producer(QObject):
    dataChanged = pyqtSignal(list)

    def __init__(self, parent=None):
        super().__init__(parent)
        self.iter = create_data()
        QTimer.singleShot(random.randint(0, 1500), self.send_data)

    def send_data(self):
        d = list(next(self.iter))
        self.dataChanged.emit(d)
        QTimer.singleShot(random.randint(0, 1500), self.send_data)


def main():
    app = QApplication(sys.argv)

    data = ((1, 7380, 7520, 7380, 7510, 7324),)
    w = MainWindow(data)
    w.show()

    p = Producer()
    p.dataChanged.connect(w.append_data_and_plot)

    sys.exit(app.exec_())


if __name__ == "__main__":
    main()

---

谢谢你的回答。在我的例子中，接收数据是随机发生的，而不是以固定的间隔。这是一个问题吗？@AFP问题是：你如何接收数据？我没有看到任何关于它的代码行，所以我不得不模拟数据，但总的来说应该没有问题。如果没有

QTimer

？@AFP我没有关于您如何获取数据的信息，那么我就不可能指出方法，再见。@AFP定期间隔不是问题，例如，我更新了我的示例，使其不定期更新。我认为您不明白如何将采集逻辑与GUI连接起来。它基于Qt，有一个很好的api，可以更新任何绘图。这太棒了！谢谢分享！