更改QLineEdit的状态时，PyQt5立即关闭

Question

我决定实施一个简单版本的GA算法。我首先使用Qt设计器创建一个.ui文档，其中包含GUI的组件和布局。然后尝试将它与python连接，但是，当来到self.dis_speed.insert（a）时，窗口立即关闭。这是整个代码：

import sys
import random
import threading
import copy
from PyQt5 import QtCore, QtGui, uic, QtWidgets
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton,QTextEdit,QAction, QLabel,QSpinBox,QLineEdit
from PyQt5.QtCore import pyqtSlot

qtCreatorFile = 'assignment1_gui.ui'    # Enter file here.

class Ui(QtWidgets.QMainWindow):
    size=0
    fit_dict={}
    individual=[]
    def __init__(self,parent=None):
        super(Ui,self).__init__(parent=parent)
        s=uic.loadUi(qtCreatorFile, self)
        self.show()
        self.but_start.clicked.connect(self.start)
        self.dis_speed=s.dis_speed
        self.dis_fit=s.dis_fit
        self.dis_speed.setReadOnly(True)
        self.dis_fit.setReadOnly(True)




    def init_ind(a):
        indi = [[] for l in range(a)]
        for i in range(0,a):
            for j in range(0,28):
                indi[i].append(chr(random.randint(32, 127)))
        return indi

    def evaluate_fit(target,a):
        count=0
        for i in range(0,len(target)):
            if target[i]==a[i]:
                count+=1
        return count

        return(28-Levenshtein.hamming(str(target),str(a)))
    def mutate(a):
        for i in range(0,len(a)):
            if(random.random()<(1/len(a))):
                a[i]=chr(random.randint(32, 127))
        return a

    def crossover(a,b):
        c=list()
        for i in range(0,len(a)):
            if random.random()<0.5:
                c.append(a[i])
            else:
                c.append(b[i])
        return c

    def ga_cross(self,individual,target):
        ind=copy.deepcopy(Ui.individual)
        speed=0
        printf=0
        while(1):
            a=random.randint(0,Ui.size-1)
            b=random.randint(0,Ui.size-1)
            if Ui.fit_dict[a]>Ui.fit_dict[b]:
                parent1=ind[a]
            else:
                parent1=ind[b]

            a=random.randint(0,Ui.size-1)
            b=random.randint(0,Ui.size-1)
            if Ui.fit_dict[a]>Ui.fit_dict[b]:
                parent2=ind[a]
            else:
                parent2=ind[b]

            child=Ui.mutate(Ui.crossover(parent1,parent2))
            a=random.randint(0,Ui.size-1)
            b=random.randint(0,Ui.size-1)
            if Ui.fit_dict[a]>Ui.fit_dict[b]:
                ind[b]=child
                Ui.fit_dict[b]=Ui.evaluate_fit(target,child)
            else:
                ind[a]=child
                Ui.fit_dict[a]=Ui.evaluate_fit(target,child)
            speed+=1
            if child==target:
                break
            if printf%10==0:
                res=max(Ui.fit_dict.items(), key=lambda x: x[1])
                Ui.tex(str(speed),str(ind[res[0]]))
            printf+=1

    @pyqtSlot()
    def tex(self,a,b):
        self.dis_speed.end(False)
        self.dis_speed.insert(a) #close immediately
        self.dis_fit.end(False)
        self.dis_fit.insert(b)
    @pyqtSlot()
    def start(self):
        target=list('methinks it is like a weasel')
        Ui.size=int(self.spin_size.value())
        Ui.individual=Ui.init_ind(Ui.size)
        s=range(0,Ui.size)
        ss=[0 for i in range(0,Ui.size)]
        Ui.fit_dict=dict(zip(s,ss))
        for i in range(0,Ui.size):
            Ui.fit_dict[i]=Ui.evaluate_fit(target,Ui.individual[i])
        Ui.ga_cross(self,Ui.individual,target)
        Ui.ga_nocross(self,Ui.individual,target)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)
    window = Ui()
    window.show()
    sys.exit(app.exec_())

以下页面是XML格式的.ui文档，可以直接复制。

<?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>957</width>
    <height>717</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget">
   <widget class="QLabel" name="lab_title">
    <property name="geometry">
     <rect>
      <x>100</x>
      <y>40</y>
      <width>811</width>
      <height>41</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>Times New Roman</family>
      <pointsize>36</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Comparision between GA with&amp;without crossover</string>
    </property>
   </widget>
   <widget class="QSpinBox" name="spin_size">
    <property name="geometry">
     <rect>
      <x>590</x>
      <y>120</y>
      <width>111</width>
      <height>41</height>
     </rect>
    </property>
    <property name="minimum">
     <number>100</number>
    </property>
    <property name="maximum">
     <number>1000</number>
    </property>
    <property name="singleStep">
     <number>100</number>
    </property>
    <property name="displayIntegerBase">
     <number>10</number>
    </property>
   </widget>
   <widget class="QLabel" name="label">
    <property name="geometry">
     <rect>
      <x>310</x>
      <y>130</y>
      <width>271</width>
      <height>20</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>Times New Roman</family>
      <pointsize>18</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Please select the size of population:</string>
    </property>
   </widget>
   <widget class="QPushButton" name="but_start">
    <property name="geometry">
     <rect>
      <x>380</x>
      <y>190</y>
      <width>191</width>
      <height>71</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>Wingdings 2</family>
      <pointsize>24</pointsize>
     </font>
    </property>
    <property name="text">
     <string>START!</string>
    </property>
   </widget>
   <widget class="QLabel" name="lab_nocr">
    <property name="geometry">
     <rect>
      <x>30</x>
      <y>330</y>
      <width>241</width>
      <height>51</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>Trajan Pro</family>
      <pointsize>18</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Speed of no crossover:</string>
    </property>
   </widget>
   <widget class="QLabel" name="lab_cr">
    <property name="geometry">
     <rect>
      <x>590</x>
      <y>330</y>
      <width>211</width>
      <height>51</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>Trajan Pro</family>
      <pointsize>18</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Speed of crossover:</string>
    </property>
   </widget>
   <widget class="QLabel" name="lab_nfit">
    <property name="geometry">
     <rect>
      <x>130</x>
      <y>410</y>
      <width>111</width>
      <height>16</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>YuMincho</family>
      <pointsize>18</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Fittest Now:</string>
    </property>
   </widget>
   <widget class="QLabel" name="lab_fit">
    <property name="geometry">
     <rect>
      <x>690</x>
      <y>410</y>
      <width>111</width>
      <height>16</height>
     </rect>
    </property>
    <property name="font">
     <font>
      <family>YuMincho</family>
      <pointsize>18</pointsize>
      <weight>75</weight>
      <bold>true</bold>
     </font>
    </property>
    <property name="text">
     <string>Fittest Now:</string>
    </property>
   </widget>
   <widget class="QLineEdit" name="dis_nspeed">
    <property name="geometry">
     <rect>
      <x>270</x>
      <y>340</y>
      <width>51</width>
      <height>31</height>
     </rect>
    </property>
   </widget>
   <widget class="QLineEdit" name="dis_nfit">
    <property name="geometry">
     <rect>
      <x>20</x>
      <y>440</y>
      <width>341</width>
      <height>41</height>
     </rect>
    </property>
   </widget>
   <widget class="QLineEdit" name="dis_speed">
    <property name="geometry">
     <rect>
      <x>800</x>
      <y>340</y>
      <width>41</width>
      <height>31</height>
     </rect>
    </property>
   </widget>
   <widget class="QLineEdit" name="dis_fit">
    <property name="geometry">
     <rect>
      <x>600</x>
      <y>440</y>
      <width>291</width>
      <height>41</height>
     </rect>
    </property>
   </widget>
  </widget>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>957</width>
     <height>22</height>
    </rect>
   </property>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
 </widget>
 <resources/>
 <connections/>
</ui>