Getting input from QLineEdit

Question

I need to get a number from my QLineEdit in the GUI and use it in a calculation and display the result in a message box but i keep getting errors

    self.connect(self.calculate, SIGNAL("clicked()"),self.showMessageBox)

    y = int(self.input1.get())
    x = 31 + y

def showMessageBox(self):
   QMessageBox.information(self,"NRC","You need " + str(x))

Answer 1

Use self.input1.text() to read the current text content of the widget.

Also note that Python will forget about x when the first method ends, so x will be unknown in showMessageBox()

Related:

• text property of QLineEdit

Answer 2

There are several problems with the way you've structured your code. It's probably easiest to just show you a working example that meets your spec, so you can see how it all goes together:

from PyQt4 import QtCore, QtGui

class Window(QtGui.QWidget):
    def __init__(self):
        QtGui.QWidget.__init__(self)
        self.input1 = QtGui.QLineEdit(self)
        self.calculate = QtGui.QPushButton('Calculate', self)
        self.calculate.clicked.connect(self.handleCalculate)
        layout = QtGui.QHBoxLayout(self)
        layout.addWidget(self.input1)
        layout.addWidget(self.calculate)

    def handleCalculate(self):
        y = int(self.input1.text())
        x = 31 + y
        self.showMessageBox(x)

    def showMessageBox(self, value):
        QtGui.QMessageBox.information(self, 'NRC', 'You need %s' % value)

if __name__ == '__main__':

    import sys
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.setGeometry(500, 300, 300, 50)
    window.show()
    sys.exit(app.exec_())