Does tab key press not register with PyQt5?

Question

With the code below, every key prints something in the terminal except for the tab key. The tab key still works though, I'm able to tab between line edits. I just can capture the event.

# i'm using PyQt5==5.11.3 and 32 bit python 3.7.1

from PyQt5.QtWidgets import QLineEdit, QLabel, QWidget, QVBoxLayout, QApplication
import sys

class Main(QWidget):
    def __init__(self):
        super().__init__()
        label = QLabel('event')
        input1 = Input()
        input2 = Input()
        layout = QVBoxLayout()
        layout.addWidget(label)
        layout.addWidget(input1)
        layout.addWidget(input2)
        self.setLayout(layout)
        self.show()

class Input(QLineEdit):
    def __init__(self):
        super().__init__()

    def keyPressEvent(self, event):
        # why doesn't tab print anything
        print(event.key())


if __name__ == "__main__":
    app = QApplication(sys.argv)
    wid = Main()
    sys.exit(app.exec_())

Have a look at [this thread](https://stackoverflow.com/questions/53856338/how-to-allow-qlineedit-detects-tab-key-pressing-event) — olinox14, Jan 21 '19 at 13:27
That captures key press, but now it doesn't process the event normally (it doesn't tab between the line edits). — mchant, Jan 21 '19 at 13:59
I don't know where to add that, but I think I can get it to work if I use pyQtSignal to inform the parent, then use the parent to move to the next input. — mchant, Jan 21 '19 at 14:46

score 1 · Accepted Answer · answered Jan 21 '19 at 15:02

You can intercept tke Tab pressed event using the event method from QLineEdit. You process your event, then you pass it to the QLineEdit.event() method.

Something like that:

import sys

from PyQt5.QtCore import QEvent, Qt
from PyQt5.QtWidgets import QLineEdit, QLabel, QWidget, QVBoxLayout, QApplication

class Main(QWidget):
    def __init__(self):
        super().__init__()
        label = QLabel('event')
        input1 = Input()
        input2 = Input()
        layout = QVBoxLayout()
        layout.addWidget(label)
        layout.addWidget(input1)
        layout.addWidget(input2)
        self.setLayout(layout)
        self.show()

class Input(QLineEdit):
    def __init__(self):
        super().__init__()

    def keyPressEvent(self, event):
        print(event.key())

    def event(self,event):
        if event.type() == QEvent.KeyPress and event.key() == Qt.Key_Tab:
            self.tabFollow()
        return QLineEdit.event(self,event)

    def tabFollow(self):
        print("tab-key pressed!")

if __name__ == "__main__":
    app = QApplication(sys.argv)
    wid = Main()
    sys.exit(app.exec_())

Thanks. This works. I tried this in the event method just with `print(event.type())` to see what prints, and it kept crashing with `TypeError: invalid result from Input.event(), a 'bool' is expected not 'NoneType'`. I didn't know it needed `return QLineEdit.event(self,event)`. — mchant, Jan 21 '19 at 19:52

Does tab key press not register with PyQt5?

1 Answers1