How to clear QVBoxLayout by a Signal?

porsol

I'm trying to clear QVBoxLayout with self.vbox.takeAt(0), but previous vboxes clog up the QWidget and would not go away. New appear on top of the old ones.

#! /usr/bin/env python
from PyQt5.QtWidgets import QApplication, QLabel, QWidget, QVBoxLayout, QHBoxLayout
from PyQt5.QtCore import QThread, QObject, pyqtSignal, pyqtSlot
import time, random

class Worker(QObject):
	CLEAR_VBOX = pyqtSignal()
	intReady = pyqtSignal(int)
	
	@pyqtSlot()
	def procCounter(self):
		for i in range(1, 100):
			self.CLEAR_VBOX.emit()
			self.intReady.emit(i)
			time.sleep(1)

class Form(QWidget):
	def __init__(self):
		super().__init__()
		
		self.obj = Worker()
		self.thread = QThread()
		self.obj.intReady.connect(self.onIntReady)
		self.obj.moveToThread(self.thread)

		self.obj.CLEAR_VBOX.connect(self.clearvbox)
		
		self.thread.started.connect(self.obj.procCounter)
		self.thread.start()
		self.initUI()


	def initUI(self):
		self.vbox = QVBoxLayout()
		self.setLayout(self.vbox)
		
		self.setGeometry(333, 333, 222, 222)
		self.show()
		
	def clearvbox(self):
		while self.vbox.count():
			# ~ # break
			self.vbox.takeAt(0)
	
	def onIntReady(self, i):
		hbox = QHBoxLayout()
						
		for ii in range(i):
			ll = QLabel(str(random.randint(1,9)))		
			hbox.addWidget(ll)

		self.vbox.addLayout(hbox)

app = QApplication([])
form = Form()
app.exec_()

SGaist

Hi,

Not a direct answer but since you want to show a random sized list of numbers why not use a QListView with a QStringListModel for that ? It would likely be simpler to manage.

porsol

@SGaist I just simplified the code with Random numbers for demonstration.

jsulm

@porsol I think you need to delete/hide widgets you're removing from the layout as removing them from the layout does not delete or hide them.

mrjj

Hi
takeAt only give you ownership back of the widget.

However, in most cases where you want to reuse layouts,
its far easier to use a place holder widget, that has the layout.
To replace it, you simply delete the placeholder widget
and allocate a new one (with empty layout) and insert into the layout.

porsol

def clearvbox(self, L = False):
	if not L:
		L = self.vbox
	if L is not None:
		while L.count():
			item = L.takeAt(0)
			
			widget = item.widget()
			
			if widget is not None:
				widget.deleteLater()
			else:
				self.clearvbox(item.layout())