Question

尝试在PyQt5和Matplotlib中使用python绘制饼图，但出现了一些问题。我可以有一个饼图和要显示的数据，但是如果我在调用某个函数时向其提供新数据，则我将尝试更新该图。

mplvl是我要添加图形的窗口小部件名称。

每次我调用此函数时，它只会添加另一个子图。我已经尝试过清除图形，清除图形，但是我无法仅仅删除并重绘图形。我认为我对Matplotlib的真正工作方式感到困惑，但是任何帮助将不胜感激。

import datetime
import calendar as cal
import sys

from PyQt5 import QtCore
from PyQt5.QtWidgets import QApplication, QDialog, QMainWindow, QMessageBox, QTableWidgetItem
from PyQt5.uic import loadUi

from matplotlib.figure import Figure
from matplotlib.backends.backend_qt5agg import (FigureCanvasQTAgg as FigureCanvas)


class MainWindow(QMainWindow):
    def __init__(self):
        super(MainWindow, self).__init__()
        loadUi('main.ui', self)

        self.date_from.setDate(QtCore.QDate(c_date.year, c_date.month, 1))
        self.date_to.setDate(QtCore.QDate(c_date.year, c_date.month, cal.monthrange(c_date.year, c_date.month)[1]))

        self.date_from.dateChanged.connect(self.fcn_date_changed)
        self.date_to.dateChanged.connect(self.fcn_date_changed)


    def fcn_date_changed(self):
        print("from: " + self.date_from.text() + " to: " + self.date_to.text())

        labels = 'Frogs', 'Hogs', 'Dogs', 'Logs'
        sizes = [15, 30, 45, 10]

        fig = Figure()
        ax1 = fig.add_subplot(111)
        ax1.set_title('Percentage Spending by Category')
        ax1.pie(sizes, labels=labels, autopct='%1.1f%%', shadow=False, startangle=90)
        main.canvas = FigureCanvas(fig)
        main.mplvl.addWidget(main.canvas)

if __name__ == "__main__":
    app = QApplication(sys.argv)
    main_window = MainWindow()
    main_window.show()
    sys.exit(app.exec_())

下面是main.ui：

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>MainWindow</class>
 <widget class="QMainWindow" name="MainWindow">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>861</width>
    <height>611</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QPushButton" name="btn_add_item">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>10</y>
      <width>71</width>
      <height>41</height>
     </rect>
    </property>
    <property name="text">
     <string>Add Item</string>
    </property>
   </widget>
   <widget class="QPushButton" name="btn_edit_item">
    <property name="geometry">
     <rect>
      <x>190</x>
      <y>540</y>
      <width>81</width>
      <height>23</height>
     </rect>
    </property>
    <property name="text">
     <string>Edit Item</string>
    </property>
   </widget>
   <widget class="QListWidget" name="recent_items">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>130</y>
      <width>351</width>
      <height>401</height>
     </rect>
    </property>
   </widget>
   <widget class="QLabel" name="lbl_recent_items">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>110</y>
      <width>251</width>
      <height>16</height>
     </rect>
    </property>
    <property name="text">
     <string>Recent Items</string>
    </property>
   </widget>
   <widget class="QPushButton" name="btn_delete_item">
    <property name="geometry">
     <rect>
      <x>280</x>
      <y>540</y>
      <width>81</width>
      <height>23</height>
     </rect>
    </property>
    <property name="text">
     <string>Delete Item</string>
    </property>
   </widget>
   <widget class="QWidget" name="mplwindow" native="true">
    <property name="geometry">
     <rect>
      <x>380</x>
      <y>130</y>
      <width>471</width>
      <height>401</height>
     </rect>
    </property>
    <property name="sizePolicy">
     <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
      <horstretch>0</horstretch>
      <verstretch>0</verstretch>
     </sizepolicy>
    </property>
    <layout class="QVBoxLayout" name="mplvl"/>
   </widget>
   <widget class="QPushButton" name="btn_view_items">
    <property name="geometry">
     <rect>
      <x>280</x>
      <y>100</y>
      <width>81</width>
      <height>23</height>
     </rect>
    </property>
    <property name="text">
     <string>View Items</string>
    </property>
   </widget>
   <widget class="QDateEdit" name="date_from">
    <property name="geometry">
     <rect>
      <x>110</x>
      <y>60</y>
      <width>110</width>
      <height>21</height>
     </rect>
    </property>
    <property name="calendarPopup">
     <bool>true</bool>
    </property>
   </widget>
   <widget class="QDateEdit" name="date_to">
    <property name="geometry">
     <rect>
      <x>250</x>
      <y>60</y>
      <width>110</width>
      <height>21</height>
     </rect>
    </property>
    <property name="calendarPopup">
     <bool>true</bool>
    </property>
   </widget>
   <widget class="QLabel" name="lbl_showing_items1">
    <property name="geometry">
     <rect>
      <x>10</x>
      <y>60</y>
      <width>101</width>
      <height>21</height>
     </rect>
    </property>
    <property name="text">
     <string>Showing items from: </string>
    </property>
   </widget>
   <widget class="QLabel" name="lbl_showing_items1_2">
    <property name="geometry">
     <rect>
      <x>230</x>
      <y>60</y>
      <width>21</width>
      <height>21</height>
     </rect>
    </property>
    <property name="text">
     <string>to:</string>
    </property>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>861</width>
     <height>21</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>

Answer 1

逻辑是：

创建一个AxesSubplot，
清理它，
调用实现绘图的函数（在您的情况下为pie(））
调用draw()进行绘画。

    # ...
    self.date_to.dateChanged.connect(self.fcn_date_changed)

    fig = Figure()
    self.canvas = FigureCanvas(fig)
    self.mplvl.addWidget(self.canvas)
    self.ax1 = fig.add_subplot(111)
    self.ax1.pie([])

def fcn_date_changed(self):
    self.ax1.clear()
    self.ax1.set_title("Percentage Spending by Category")
    print("from: " + self.date_from.text() + " to: " + self.date_to.text())
    labels = "Frogs", "Hogs", "Dogs", "Logs"
    sizes = [15, 30, 45, 10]
    self.ax1.pie(
        sizes, labels=labels, autopct="%1.1f%%", shadow=False, startangle=90
    )
    self.ax1.figure.canvas.draw()

Matplotlib和PyQt5绘图图

1 个答案: