PyDev无法识别PyQt5

我正在关注有关pyqt的教程，并获得了以下代码:

I am following a tutorial on pyqt, and got this code:

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class Example(QWidget):

    def __init__(self):
        super(Example, self).__init__()
        self.initUI()

    def initUI(self):
        cb = QCheckBox('Show title', self)
        cb.move(20, 20)
        cb.toggle()
        cb.stateChanged.connect(self.changeTitle)

        self.setGeometry(300, 300, 250, 150)
        self.setWindowTitle('Checkbox')
        self.show()

    def changeTitle(self, state):
        if state == Qt.Checked:
            self.setWindowTitle('Checkbox')
        else: self.setWindowTitle('Unchecked!')

def main():
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()

我在Eclipse上使用PyDev.可以说该代码运行良好，但是令人尴尬的是PyDev用红线在Qt/Q下加了下划线，当它悬停时表示未定义变量:< ..> .如果未定义，那么我的代码如何正确运行?显然，这应该是PyDev的问题.我删除了python解释器(它指向的是python2.7而不是3.4)，并将其读为正确的版本；但这没用.有趣的是，它可以识别PyQt4并坚持使用该控件而不是PyQt5.

I'm using PyDev on Eclipse. Suffice it to say that the code runs fine, but what is awkward is that PyDev underlines anything Qt/Q with a red line which when hovered over says Undefined variable: <..>. If it is undefined then how is it that my code runs without errors? Clearly this ought to be a problem with PyDev. I've removed the python interpreter (it was pointing to python2.7 instead of 3.4) and readded it as the correct version; but that didn't work. Interestingly enough, it recognises PyQt4 and insists on using widgets from that instead of PyQt5.

请大家注意，上面的代码示例来自另一台具有PyQt5的笔记本电脑.这两个项目均来自PyDev，并且都具有Ubuntu 15.04.我在当前计算机上导入项目的过程很可能使PyDev解析了所需的库.关于PyDev为什么不识别PyQt5的问题，有人可以解决吗?

Just so you guys are aware, the code sample above is from another laptop which had PyQt5 as well. Both projects were from PyDev, and both had Ubuntu 15.04. It's possible that my importing of the project on my current machine messed up PyDev parsing the required libraries. Does anyone have a solution as to why PyDev doesn't recognise PyQt5?