在编辑行内按空格键时如何调用函数

Question

每当我在lineEdit中按空格键时，我想调用一个函数来检查lineEdit中的字数。但我该怎么做呢。执行完python文件后，按"开始游戏"转到lineEdit。谢谢
这是我的代码：

from PyQt5.QtWidgets import QMainWindow, QApplication, QLabel, QLineEdit, QPushButton, QTextBrowser, QStackedWidget, QWidget, QLCDNumber, QComboBox
from PyQt5 import uic
import sys
from PyQt5.QtGui import QKeyEvent
from PyQt5.QtCore import QThread, pyqtSignal, Qt
import random
class UI(QMainWindow):
def __init__(self):
super(UI, self).__init__()
# Load the ui file
uic.loadUi("Typing_test_UI.ui", self)
# Define our widgets
self.textBrowser = self.findChild(QTextBrowser, "textBrowser")
self.lineEdit = self.findChild(QLineEdit, "lineEdit")
self.counter = self.findChild(QLCDNumber, "counter")
self.startBtn = self.findChild(QPushButton, "startBtn")
self.timeCombo = self.findChild(QComboBox, "timeCombo")
self.difficultyCombo = self.findChild(QComboBox, "difficultyCombo")
self.stackedWidget = self.findChild(QStackedWidget, "stackedWidget")
self.startPage = self.findChild(QWidget, "startPage")
self.gamePage = self.findChild(QWidget, "gamePage")
self.scorePage = self.findChild(QWidget, "scorePage")
self.highScoreLabel = self.findChild(QLabel, "highScoreLabel")
self.scoreLabel = self.findChild(QLabel, "scoreLabel")
self.retryBtn = self.findChild(QPushButton, "retryBtn")

self.space_count = 0

self.startBtn.clicked.connect(self.start_game)
self.retryBtn.clicked.connect(self.goto_home_page)

# Show the app
self.show()
def start_game(self):
self.stackedWidget.setCurrentWidget(self.gamePage)
self.textBrowser.clear()
with open("Typing_sentences.txt", "r") as f:
all_texts = f.readlines()
lines_of_text = len(all_texts)
self.textBrowser.append(all_texts[random.randint(0, lines_of_text-1)])
def goto_home_page(self):
self.stackedWidget.setCurrentWidget(self.startPage)

app = QApplication(sys.argv)
UIWindow = UI()
app.exec_()

我的代码中的一个函数的句子：
他发现自己坐在电脑前，输入脑海中的任何内容。他在一个名为"十个快速手指"的网站上。这个网站测试了你打字的速度。于是他打字。他目前正在打字，这在某种程度上很奇怪。他现在正在描述自己是如何打字的
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ui文件：

<?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>801</width>
<height>443</height>
</rect>
</property>
<property name="minimumSize">
<size>
<width>801</width>
<height>443</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>801</width>
<height>443</height>
</size>
</property>
<property name="windowTitle">
<string>MainWindow</string>
</property>
<widget class="QWidget" name="centralwidget">
<property name="sizePolicy">
<sizepolicy hsizetype="Expanding" vsizetype="Expanding">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<layout class="QVBoxLayout" name="verticalLayout">
<item>
<widget class="QStackedWidget" name="stackedWidget">
<property name="currentIndex">
<number>2</number>
</property>
<widget class="QWidget" name="startPage">
<layout class="QVBoxLayout" name="verticalLayout_2">
<item>
<widget class="QWidget" name="widget_3" native="true">
<widget class="QComboBox" name="timeCombo">
<property name="geometry">
<rect>
<x>280</x>
<y>60</y>
<width>201</width>
<height>41</height>
</rect>
</property>
<property name="font">
<font>
<pointsize>11</pointsize>
</font>
</property>
<item>
<property name="text">
<string>1 Minute</string>
</property>
</item>
<item>
<property name="text">
<string>2 Minutes</string>
</property>
</item>
<item>
<property name="text">
<string>5 Minutes</string>
</property>
</item>
<item>
<property name="text">
<string>10 Minutes</string>
</property>
</item>
</widget>
<widget class="QComboBox" name="difficultyCombo">
<property name="geometry">
<rect>
<x>280</x>
<y>130</y>
<width>201</width>
<height>41</height>
</rect>
</property>
<property name="font">
<font>
<pointsize>12</pointsize>
</font>
</property>
<item>
<property name="text">
<string>Easy</string>
</property>
</item>
<item>
<property name="text">
<string>Medium</string>
</property>
</item>
<item>
<property name="text">
<string>Hard</string>
</property>
</item>
</widget>
<widget class="QPushButton" name="startBtn">
<property name="geometry">
<rect>
<x>230</x>
<y>230</y>
<width>301</width>
<height>61</height>
</rect>
</property>
<property name="font">
<font>
<pointsize>16</pointsize>
</font>
</property>
<property name="text">
<string>Start Game</string>
</property>
</widget>
</widget>
</item>
</layout>
</widget>
<widget class="QWidget" name="gamePage">
<layout class="QGridLayout" name="gridLayout_2">
<item row="0" column="0" alignment="Qt::AlignRight|Qt::AlignTop">
<widget class="QWidget" name="widget_2" native="true">
<property name="layoutDirection">
<enum>Qt::LeftToRight</enum>
</property>
<layout class="QHBoxLayout" name="horizontalLayout">
<item alignment="Qt::AlignRight">
<widget class="QLCDNumber" name="counter">
<property name="minimumSize">
<size>
<width>150</width>
<height>30</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>150</width>
<height>16777215</height>
</size>
</property>
<property name="layoutDirection">
<enum>Qt::RightToLeft</enum>
</property>
</widget>
</item>
</layout>
</widget>
</item>
<item row="1" column="0">
<widget class="QWidget" name="widget" native="true">
<layout class="QGridLayout" name="gridLayout">
<item row="0" column="0" colspan="2">
<widget class="QTextBrowser" name="textBrowser"/>
</item>
<item row="1" column="0" colspan="2">
<widget class="QLineEdit" name="lineEdit">
<property name="sizePolicy">
<sizepolicy hsizetype="Expanding" vsizetype="Expanding">
<horstretch>0</horstretch>
<verstretch>0</verstretch>
</sizepolicy>
</property>
<property name="minimumSize">
<size>
<width>0</width>
<height>45</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>16777215</width>
<height>45</height>
</size>
</property>
</widget>
</item>
</layout>
</widget>
</item>
</layout>
</widget>
<widget class="QWidget" name="scorePage">
<widget class="QLabel" name="scoreLabel">
<property name="geometry">
<rect>
<x>240</x>
<y>90</y>
<width>300</width>
<height>71</height>
</rect>
</property>
<property name="minimumSize">
<size>
<width>300</width>
<height>0</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>16777215</width>
<height>100</height>
</size>
</property>
<property name="font">
<font>
<pointsize>20</pointsize>
</font>
</property>
<property name="text">
<string>Score: 0</string>
</property>
</widget>
<widget class="QPushButton" name="retryBtn">
<property name="geometry">
<rect>
<x>652</x>
<y>320</y>
<width>121</width>
<height>64</height>
</rect>
</property>
<property name="minimumSize">
<size>
<width>64</width>
<height>64</height>
</size>
</property>
<property name="text">
<string>Retry</string>
</property>
<property name="iconSize">
<size>
<width>64</width>
<height>64</height>
</size>
</property>
</widget>
<widget class="QLabel" name="highScoreLabel">
<property name="geometry">
<rect>
<x>291</x>
<y>185</y>
<width>200</width>
<height>18</height>
</rect>
</property>
<property name="minimumSize">
<size>
<width>200</width>
<height>0</height>
</size>
</property>
<property name="maximumSize">
<size>
<width>16777215</width>
<height>50</height>
</size>
</property>
<property name="font">
<font>
<pointsize>9</pointsize>
</font>
</property>
<property name="text">
<string>High Score: 0</string>
</property>
</widget>
</widget>
</widget>
</item>
</layout>
</widget>
<widget class="QMenuBar" name="menubar">
<property name="geometry">
<rect>
<x>0</x>
<y>0</y>
<width>801</width>
<height>26</height>
</rect>
</property>
<widget class="QMenu" name="menuPapers">
<property name="title">
<string>Options</string>
</property>
<widget class="QMenu" name="menuTest_papers">
<property name="title">
<string>Test papers</string>
</property>
<addaction name="actionRandom"/>
<addaction name="actionChoose"/>
</widget>
<addaction name="menuTest_papers"/>
<addaction name="actionReset"/>
</widget>
<addaction name="menuPapers"/>
</widget>
<action name="actionRandom">
<property name="text">
<string>Random</string>
</property>
</action>
<action name="actionChoose">
<property name="text">
<string>Choose</string>
</property>
</action>
<action name="actionReset">
<property name="text">
<string>Reset High Score</string>
</property>
</action>
</widget>
<resources/>
<connections/>
</ui>

Answer 1

下面是一个按照建议在QLineEdit上安装事件过滤器的示例。有关详细信息和解释，请参阅内联注释。

...
class UI(QMainWindow):
def __init__(self):
super(UI, self).__init__()
# Load the ui file
uic.loadUi("Typing_test_UI.ui", self)
# Define our widgets
...
...
self.spaceFilter = SpaceFilter(parent=self)  # init filter
self.spaceFilter.spacePressed.connect(self.my_function)  # connect to the signal
self.lineEdit.installEventFilter(self.spaceFilter)  # install on lineedit
self.space_count = 0
self.startBtn.clicked.connect(self.start_game)
self.retryBtn.clicked.connect(self.goto_home_page)
# Show the app
self.show()

def my_function(self):   # custom function that runs when space bar is
for i in range(5):   # pressed while typing in the line edit
for i in range(1000):
print(str(i), end="r")
def start_game(self):
self.stackedWidget.setCurrentWidget(self.gamePage)
self.textBrowser.clear()
with open("list1.txt", "r") as f:
all_texts = f.readlines()
lines_of_text = len(all_texts)
self.textBrowser.append(all_texts[random.randint(0, lines_of_text-1)])
def goto_home_page(self):
self.stackedWidget.setCurrentWidget(self.startPage)
class SpaceFilter(QObject):  # the event filter object
spacePressed = pyqtSignal()   # the signal emited when space bar detected
def eventFilter(self, widget, event):
if event.type() == QEvent.KeyPress:  # listen for key press events
if event.key() == Qt.Key.Key_Space:  # if the key is the space bar
self.spacePressed.emit()         # emit the signal
return False