import sys

from PySide import QtCore
from PySide import QtGui


class MyDialog(QtGui.QDialog):
    def __init__(self, parent=None):
        super(MyDialog, self).__init__(parent)

        boxlayout = QtGui.QBoxLayout(QtGui.QBoxLayout.TopToBottom, self)

        self.lineedit = QtGui.QLineEdit()
        boxlayout.addWidget(self.lineedit)

        self.button = QtGui.QPushButton("Abschicken")
        self.button.clicked.connect(self.buttonClicked)
        boxlayout.addWidget(self.button)

        self.label = QtGui.QLabel()
        boxlayout.addWidget(self.label)

        self.setLayout(boxlayout)

    def buttonClicked(self):
        self.label.setText(self.lineedit.text())
        self.lineedit.setText("")

if __name__ == "__main__":
    app = QtGui.QApplication(sys.argv)
    dialog = MyDialog()
    sys.exit(dialog.exec_())