PyQt:数据不是JSON可序列化的 [英] PyQt : data is not JSON serializable

问题描述

我是PyQt GUI的新手.我想获取QLineEdit文本框的数据，为此，我正在使用text()方法.我正在获取数据，但数据类型为QString.我需要将其作为json数据传输到服务器，为此，我正在使用json.dumps()方法-但出现错误.

I am new to PyQt GUI. I want to get the data of a QLineEdit text box, and for that I am using the text() method. I am getting the data, but the data type is a QString. I need to transmit this as json data to a server, and for that I am using the json.dumps() method - but I get an error.

import sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
import pygame.camera
import pygame.image
import json

app = QApplication(sys.argv)

class stackedExample(QWidget):

   def __init__(self):
      super(stackedExample, self).__init__()
      self.current_module = 'GUI'
      print (self.current_module)

      self.takeFinger = False

      self.personaldata = None
      self.vehicledata = None

      self.leftlist = QListWidget ()
      self.leftlist.insertItem (0, 'Personal Info' )

      self.stack1 = QWidget()

      self.stack1UI()

      self.Stack = QStackedWidget (self)
      self.Stack.addWidget (self.stack1)

      hbox = QHBoxLayout(self)
      hbox.addWidget(self.leftlist)
      hbox.addWidget(self.Stack)

      self.setLayout(hbox)
      self.leftlist.currentRowChanged.connect(self.display)
      self.setGeometry(450, 120, 30,30)

      self.show()
      sys.exit(app.exec_())
      print "2"

   def stack1UI(self):
      layout = QFormLayout()
      self.s1 = QLabel("System ID")
      self.s1_val = QLineEdit()
      layout.addRow(self.s1,self.s1_val)
      self.s2 = QLabel("Driver Name")
      self.s2_val = QLineEdit()
      layout.addRow(self.s2,self.s2_val)
      self.s3 = QLabel("Aadhar ID")
      self.s3_val = QLineEdit()
      layout.addRow(self.s3,self.s3_val)

      self.s4 = QLabel("Driver Phone")
      self.s4_val = QLineEdit()
      layout.addRow(self.s4,self.s4_val)

      self.s5 = QLabel("Age")
      self.s5_val = QLineEdit()
      layout.addRow(self.s5,self.s5_val)

      sex = QHBoxLayout()
      sex.addWidget(QRadioButton("Male"))
      sex.addWidget(QRadioButton("Female"))
      layout.addRow(QLabel("Sex"),sex)
      self.b4 = QPushButton("&Save")
      self.b4.setDefault(True)
      self.b4.clicked.connect(self.personalData)
      layout.addWidget(self.b4)
      self.stack1.setLayout(layout)

   def personalData(self):
      print (self.s1_val.toPlainText())
      print type(self.s1_val.text())
      if (self.s1_val.text().isEmpty()):
         print "s1 is empty"
         #self.popup_window()
      if (self.s2_val.text().isEmpty()):
         print "s2 is empty"
      if (self.s3_val.text().isEmpty()):
         print "s3 is empty"
      if (self.s4_val.text().isEmpty()):
         print "s4 is empty"
      if (self.s5_val.text().isEmpty()):
         print "s5 is empty"

      if(not self.s1_val.text().isEmpty() and not self.s2_val.text().isEmpty()):
         #Data1 = {'systemID':self.s1_val.text(),'driverName': self.s2_val.text(),'aadharID': self.s3_val.text(),'driverPhone': self.s4_val.text(),'Age': self.s5_val.text()}
         Data1 = {'systemID': self.s1_val.toPlainText()}
         self.personaldata = json.dumps(self.s1_val.text())
         print ("personal json ready")

   def display(self,i):
      self.Stack.setCurrentIndex(i)

   def on_takephoto(self):
      self.showImage('photo.jpg')
   def getFinger(self):
      return self.takeFinger 
   def setFinger(self):
      self.takeFinger = True

错误是:

    <class 'PyQt4.QtCore.QString'>
    Traceback (most recent call last):
      File "/home/hearthacker/Desktop/gui code sagar/stacked.py", line 138, in personalData
        self.personaldata = json.dumps(self.s1_val.text())
      File "/usr/lib/python2.7/json/__init__.py", line 243, in dumps
        return _default_encoder.encode(obj)
      File "/usr/lib/python2.7/json/encoder.py", line 207, in encode
        chunks = self.iterencode(o, _one_shot=True)
      File "/usr/lib/python2.7/json/encoder.py", line 270, in iterencode
        return _iterencode(o, 0)
      File "/usr/lib/python2.7/json/encoder.py", line 184, in default
        raise TypeError(repr(o) + " is not JSON serializable")
    TypeError: PyQt4.QtCore.QString(u's') is not JSON serializable

推荐答案

如果将PyQt5或Python3与PyQt4一起使用，则不会出现此类错误，因为PyQt总是会尽可能返回普通的Python类型.但是您将Python2与PyQt4结合使用，这意味着您必须明确要求该行为.

If you use PyQt5, or Python3 with PyQt4, you will not get this kind of error, because PyQt will always return ordinary Python types whenever possible. But you are using Python2 with PyQt4, which means you have to explicitly request that behaviour.

为此，请按以下步骤更改导入:

To do that, change your imports as follows:

import sip
sip.setapi('QString', 2)
sip.setapi('QVariant', 2)
from PyQt4.QtCore import *
from PyQt4.QtGui import *

(请注意，setapi调用必须必须在应用程序中首次导入任何PyQt模块之前.)

(And note that the setapi calls must go before the first import of any PyQt modules in your application).

有了这个，您还需要将代码简化为此:

With that in place, you will also need to simplify your code to this:

   def personalData(self):
      print type(self.s1_val.text())
      if not self.s1_val.text():
         print "s1 is empty"
         #self.popup_window()
      if not self.s2_val.text():
         print "s2 is empty"
      if not self.s3_val.text():
         print "s3 is empty"
      if not self.s4_val.text():
         print "s4 is empty"
      if not self.s5_val.text():
         print "s5 is empty"

      if self.s1_val.text() and self.s2_val.text():
         Data1 = {'systemID': self.s1_val.text()}
         self.personaldata = json.dumps(Data1)
         print ("personal json ready")

PS:

如果您刚开始学习Python和/或PyQt，我强烈建议您尽可能使用Python3和PyQt5.

If you're just starting out learning Python and/or PyQt, I would strongly recommend that you use Python3 and PyQt5 if at all possible.

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