#coding:utf-8
from __future__ import division
import sys
from math import *
from PyQt4 import QtCore
from PyQt4 import QtGui
class Form(QtGui.QDialog):
def __init__(self, parent=None):
super(Form, self).__init__(parent)
self.browser = QtGui.QTextBrowser()
self.lineedit = QtGui.QLineEdit("Type an expression and press Enter")
self.lineedit.selectAll() #设置文本全选
layout = QtGui.QVBoxLayout()
layout.addWidget(self.browser)
layout.addWidget(self.lineedit)
self.setLayout(layout)
self.lineedit.setFocus() #设置光标定位
self.connect(self.lineedit, QtCore.SIGNAL("returnPressed()"), self.updateUi)
self.setWindowTitle("Calculate")
def updateUi(self):
try:
text = unicode(self.lineedit.text())
self.browser.append("{}={}".format(text,eval(text)))
except:
self.browser.append(u"{} is invalid".format(text))
app = QtGui.QApplication(sys.argv)
form = Form()
form.show()
app.exec_()
