Matplotlib 'key_press_event' 没有响应

Question

在图上用鼠标点击： self.canvas.Fig.canvas.mpl_connect('button_press_event', self.button_press)

我可以通过在状态栏 self.statusBar().showMessage("Key pressed", 400)

中打印 "Button pressed" 来接收信号并生成答案

但出于某种原因，同一段代码不适用于按键（键盘）按下： self.canvas.Fig.canvas.mpl_connect('key_press_event', self.key_press)

消息"Key pressed"没有出现，意味着没有事件发生或没有收到信号。

这是我的 MWE，包含所有必需品类:

import sys
import matplotlib 
matplotlib.use("Qt5Agg")
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import QApplication, QMainWindow, QSizePolicy

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


class MyMplCanvas(FigureCanvas):
    def __init__(self, parent=None, width=5, height=4, dpi=100,data=[[]],timedelay=[],wavelength=[]):
        self.Fig = Figure(figsize=(width, height), dpi=dpi)
        self.Dataplot = self.Fig.add_subplot(111)

        self.compute_initial_figure(data,timedelay, wavelength)    

        FigureCanvas.__init__(self, self.Fig)
        self.setParent(parent)
        FigureCanvas.setSizePolicy(self,QSizePolicy.Expanding,QSizePolicy.Expanding)
        FigureCanvas.updateGeometry(self)

    def compute_initial_figure(self,data,timedelay,wavelength):
        pass

class MyStaticMplCanvas(MyMplCanvas):  
    def __init__(self, *args, **kwargs):
        MyMplCanvas.__init__(self, *args, **kwargs)

    def compute_initial_figure(self,data,timedelay,wavelength): 
        self.Dataplot.set_xlabel('Wavelength, nm')
        self.Dataplot.set_ylabel('Time delay, ~s')

class GraphView(QMainWindow):
    def __init__(self):
        QMainWindow.__init__(self)
        self.main_widget = QtWidgets.QWidget(self)

        self.canvas = MyStaticMplCanvas(self.main_widget, width=8, height=8, dpi=100,data=[[]],timedelay=[],wavelength=[])

        self.canvas.Fig.canvas.mpl_connect('key_press_event', self.key_press)
        self.canvas.Fig.canvas.mpl_connect('button_press_event', self.button_press)

        self.layoutMain = QtWidgets.QHBoxLayout(self.main_widget)      
        self.layoutFigure = QtWidgets.QHBoxLayout()
        self.layoutMain.addLayout(self.layoutFigure)   
        self.layoutFigure.addWidget(self.canvas)


        self.main_widget.setFocus()
        self.setCentralWidget(self.main_widget)

    def key_press(self,event):
        self.statusBar().showMessage("Key pressed", 400)

    def button_press(self,event):
        self.statusBar().showMessage("Button pressed", 400) 

def main():
    app = QApplication( sys.argv )
    a=GraphView()
    a.show() 
    app.exec()

if __name__ == '__main__':
    sys.exit(main())

我的代码有什么问题？

Answer 1

我找到了解决方案here

之后

self.canvas = MyStaticMplCanvas(self.main_widget, width=8, height=8, dpi=100,data=[[]],timedelay=[],wavelength=[])

添加

self.canvas.setFocusPolicy( QtCore.Qt.ClickFocus )
self.canvas.setFocus()

单击 canvas 使其具有焦点，然后您将看到 key_presses

Answer 2

如果您不想每次都点击 canvas 键，您可以执行以下操作，当您将鼠标悬停在 canvas 上时，焦点会自动切换到 canvas它与你的光标。将此添加到您的 GraphView.__init__():

self.cid_enter = self.canvas.mpl_connect('axes_enter_event', self.on_enter_event)

并将 on_enter_event 方法添加到您的 GraphView class:

def on_enter_event(self, _):
    self.canvas.setFocus()

您也不需要更改 FocusPolicy 即可工作。

顺便说一句，您不需要执行 self.canvas.Fig.canvas 来引用 canvas 对象，因为它是循环的。 self.canvas 已经是 canvas 对象。从理论上讲，您可以无限期地执行 self.canvas.Fig.canvas.Fig.canvas 等等，并且仍然会引用同一个对象。

Matplotlib 'key_press_event' 没有响应

Matplotlib 'key_press_event' does not respond

python

matplotlib

python-3.x

pyqt5