Solution of https://stackoverflow.com/questions/46028440/input-style-input-from-a-pyqt-form

main-pyqt4.py

import sys
from PyQt4.QtGui import *
from PyQt4.QtCore import *

def process(text):
    # Emulate processing
    return [c for c in text]

class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.setLayout(QVBoxLayout())
        self.le = QLineEdit(self)
        self.te = QTextEdit(self)

        self.layout().addWidget(self.le)
        self.layout().addWidget(self.te)

        self.le.returnPressed.connect(self.onReturnPressed)

    def onReturnPressed(self):
        # process

        output = process(self.le.text())

        [self.te.append(c) for c in output]

def main():

    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()  

main-pyqt5.py

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

def process(text):
    # Emulate processing
    return [c for c in text]

class Widget(QWidget):
    def __init__(self, parent=None):
        QWidget.__init__(self, parent)
        self.setLayout(QVBoxLayout())
        self.le = QLineEdit(self)
        self.te = QTextEdit(self)

        self.layout().addWidget(self.le)
        self.layout().addWidget(self.te)

        self.le.returnPressed.connect(self.onReturnPressed)

    def onReturnPressed(self):
        # process

        output = process(self.le.text())

        [self.te.append(c) for c in output]

def main():

    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())


if __name__ == '__main__':
    main()