Question

这是一个简单的堆栈显示程序，带有使用PyQt5和Python3.3的GUI。在###Error####

之间突出显示的Gui程序错误区域

#Modules
import sys
from PyQt5 import QtGui, QtCore, QtWidgets
import stacks_queues

#Classes
class MainWindow(QtWidgets.QMainWindow):
    '''Main Window'''

    #Constructor
    def __init__(self):
        super(MainWindow,self).__init__()
        self.createUI()   

    #Methods

###Error###
    def createUI(self):
        self.stack = stacks_queues.Stack()
        #Title
        self.setWindowTitle('Section 2.4: Stacks and queues')
        #Window Components
        self.mainViewWidget = QtWidgets.QWidget()
        #Layouts
        self.mainViewWidget.setLayout(self.mainGrid(self.stack))
        self.setCentralWidget(self.mainViewWidget)
###Error###

    def mainGrid(self,stack):
        #Layout components
        self.mainLayout = QtWidgets.QVBoxLayout()
        self.addRemoveLayout = QtWidgets.QGridLayout()
        self.pushButtonLayout = QtWidgets.QHBoxLayout()
        #Create components
        #Labels
        self.titleLabel = QtWidgets.QLabel('Implementation of a Stack', self)
        self.counterLabel = QtWidgets.QLabel('Number of items in stack: 0', self)
        self.contentsLabel = QtWidgets.QLabel('Contents of stack', self)
        self.addWordLabel = QtWidgets.QLabel('Word to add:', self)
        self.removeWordLabel = QtWidgets.QLabel('Word being removed', self)
        #Buttons
        self.pushButton = QtWidgets.QPushButton('Push', self)
        self.popButton = QtWidgets.QPushButton('Pop', self)
        #Line Edit
        self.addWordLineEdit = QtWidgets.QLineEdit('', self)
        self.removeWordLineEdit = QtWidgets.QLineEdit('Test', self)
        self.removeWordLineEdit.isReadOnly()
        #Text Edit
        self.stackTextEdit = QtWidgets.QTextEdit('', self)
        self.stackTextEdit.isReadOnly()
        #Add Widgets
        self.mainLayout.addWidget(self.titleLabel)
        self.addRemoveLayout.addWidget(self.addWordLabel, 0,0)
        self.addRemoveLayout.addWidget(self.removeWordLabel, 1,0)
        self.addRemoveLayout.addWidget(self.addWordLineEdit, 0,1)
        self.addRemoveLayout.addWidget(self.removeWordLineEdit, 1,1)
        self.mainLayout.addLayout(self.addRemoveLayout)
        self.mainLayout.addWidget(self.contentsLabel)
        self.mainLayout.addWidget(self.stackTextEdit)
        self.mainLayout.addWidget(self.counterLabel)
        self.pushButtonLayout.addWidget(self.pushButton)
        self.pushButtonLayout.addWidget(self.popButton)
        self.mainLayout.addLayout(self.pushButtonLayout)
        #Connections
        self.pushButton.clicked.connect(self.pushStack(self.stack))
        self.popButton.clicked.connect(self.popStack)
        return self.mainLayout

###Error###
    def pushStack(self,stack):
        item = self.addWordLineEdit.text()
        self.stack.push(item)
        #Re-draw Window
        self.mainViewWidget = QtWidgets.QWidget()
        self.mainViewWidget.setLayout(self.mainGrid(self.stack))
        self.setCentralWidget(self.mainViewWidget)
###Error###

    def popStack(self):
        #Not finished yet
        pass


#Functions
def Main():
    '''Main Program'''
    #Creates new application
    application = QtWidgets.QApplication(sys.argv)
    #Creates new instance of MainWindow
    mainWindow = MainWindow()
    #Display MainWindow
    mainWindow.show()
    #Keep MainWindow on top
    mainWindow.raise_()
    #Monitor for events
    application.exec_()
#Run Main
Main()

导入的程序

class Stack():
    '''Stack data'''
    #Attributes
    items = []
    maxsize = 0

    #Methods
    def push(self,item):
        self.items.append(item)

    def pop(self,item):
        self.items.pop()

    def isEmpty(self):
        if self.items:
            return False
        else:
            return True

    def size(self):
        self.maxsize = len(self.items)

错误是1993行，所以我只会显示不断重复的主要错误。

Traceback (most recent call last):
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py", line 92, in <module>
    Main()
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py",     line 84, in Main
    mainWindow = MainWindow()
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py",     line 13, in __init__
    self.createUI()
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py", line 23, in createUI
    self.mainViewWidget.setLayout(self.mainGrid(self.stack))
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py",     line 62, in mainGrid
    self.pushButton.clicked.connect(self.pushStack(self.stack))
  File "C:\Users\Luke\Documents\A-Level-Work\A2\Computing\COMP 3\stack_queues_gui.py",         line 71, in pushStack

只有在python超过其最大递归深度时，错误才会继续重复第62行和第71行。

只有在添加pushStack后才会发生大量错误，所以我不知道如何解决这个问题，因为我只有A2级python知识。该计划很好，Stack被调入MainWindow并在mainGrid中使用。

Answer 1

您创建了一个无限递归：

 def mainGrid(self,stack):
     # ...
    self.pushButton.clicked.connect(self.pushStack(self.stack))

呼叫

def pushStack(self,stack):
    # ...
    self.mainViewWidget.setLayout(self.mainGrid(self.stack))

在那里查看self.mainGrid()？但是self.mainGrid()会调用self.pushStack()，而您的代码中没有任何地方可以突破该循环。

你需要在这里删除一个或另一个调用，或者确定递归调用应该实现什么，并创建条件，其中两个方法之一不调用另一个。

每次在堆栈上推送内容时，您很可能不必从头开始重新创建self.mainViewWidget。另外，如果您想在self.pushStack 点击时调用pushButton（而不是在将操作连接到按钮时），则需要 not 直接调用它：

self.pushButton.clicked.connect(self.pushStack)

请注意，现在连接了self.pushStack 方法，而不是返回值。

此处无理由将self.stack传递给self.pushStack();该方法也可以在没有self.stack参数的情况下访问stack

def pushStack(self):
    # ...
    self.stack.push(item)

在另一个类中使用一个类的实例

1 个答案: