PyQt5: detect a new inserted tab with QTabWidget::tabInserted(int index) - pyqt5

Question

I'm new in PyQt5. I made a tabWidget where I was able to connect a button to add tabs dynamically and remove/close them. Before inserting tabs with button.Clicked, there's one open (already inserted) tab saying "no tabs are open". I would like to close this tab after inserting a new tab and reopen the tab after closing all new tabs (when no tabs are open). I couldn't find any example on how to use QTabWidget::tabInserted(int index) from http://doc.qt.io/qt-5/qtabwidget.html. Does anyone know how to use tabInserted and tabRemoved to detect when triggered. I would like to increment each time a tab is inserted and decrement when removed, to know when there are open tabs and no open tabs. Thanks
self.toolButton.clicked.connect(self.button_addtab)
self.tabWidget.tabCloseRequested.connect(self.close_tab)
def button_addtab(self, MainWindow):
_translate = QtCore.QCoreApplication.translate
self.tab_2 = QtWidgets.QWidget()
self.tab_2.setObjectName("tab_2")
self.tabWidget.addTab(self.tab_2, "")
self.tabWidget.setCurrentIndex(pages-0)
self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab_2), _translate("MainWindow", "Second_tab"))
def close_tab(self, index):
self.tabWidget.removeTab(index)
I tried this:
if self.tabWidget.count() <= 0:
#Add the "no tab open" tab
self.tab_3 = QtWidgets.QWidget()
self.tab_3.setObjectName("tab_3")
self.tabWidget.addTab(self.tab_3, "")
_translate = QtCore.QCoreApplication.translate
self.tabWidget.setTabText(self.tabWidget.indexOf(self.tab_3), _translate("MainWindow", "Info"))
elif self.tabWidget.count() > 0:
self.tabWidget.removeTab(self.tabWidget.indexOf(self.tab_3))
This work, but it doesn't add after closing and it reopens after one more tab is added. That's why I would like to use tabInserted

Answer 1

See class TabWidget
import sys
from PyQt5.QtCore import Qt, QRect
from PyQt5.QtGui import QColor, QPainter
from PyQt5.QtWidgets import (QApplication, QWidget, QMainWindow, QAction,
QVBoxLayout, QTabWidget, QFileDialog, QPlainTextEdit, QHBoxLayout)
lineBarColor = QColor(53, 53, 53)
lineHighlightColor = QColor('#00FF04')
class TabWidget(QTabWidget):
def __init__(self, parent=None):
super(TabWidget, self).__init__(parent)
# This virtual handler is called after a tab was removed from position index.
def tabRemoved(self, index):
print("\n tab was removed from position index -> {}".format(index))
# This virtual handler is called after a new tab was added or inserted at position index.
def tabInserted(self, index):
print("\n New tab was added or inserted at position index -> {}".format(index))
class NumberBar(QWidget):
def __init__(self, parent=None):
super().__init__(parent)
self.editor = parent
layout = QVBoxLayout(self)
self.editor.blockCountChanged.connect(self.update_width)
self.editor.updateRequest.connect(self.update_on_scroll)
self.update_width('001')
def mousePressEvent(self, QMouseEvent):
print("\n - class NumberBar(QWidget): \n\tdef mousePressEvent(self, QMouseEvent):")
def update_on_scroll(self, rect, scroll):
if self.isVisible():
if scroll:
self.scroll(0, scroll)
else:
self.update()
def update_width(self, string):
width = self.fontMetrics().width(str(string)) + 10
if self.width() != width:
self.setFixedWidth(width)
def paintEvent(self, event):
if self.isVisible():
block = self.editor.firstVisibleBlock()
height = self.fontMetrics().height()
number = block.blockNumber()
painter = QPainter(self)
painter.fillRect(event.rect(), lineBarColor)
painter.setPen(Qt.white)
painter.drawRect(0, 0, event.rect().width() - 1, event.rect().height() - 1)
font = painter.font()
current_block = self.editor.textCursor().block().blockNumber() + 1
while block.isValid():
block_geometry = self.editor.blockBoundingGeometry(block)
offset = self.editor.contentOffset()
block_top = block_geometry.translated(offset).top()
number += 1
rect = QRect(0, block_top, self.width() - 5, height)
if number == current_block:
font.setBold(True)
else:
font.setBold(False)
painter.setFont(font)
painter.drawText(rect, Qt.AlignRight, '%i' % number)
if block_top > event.rect().bottom():
break
block = block.next()
painter.end()
class Content(QWidget):
def __init__(self, text):
super(Content, self).__init__()
self.editor = QPlainTextEdit()
self.editor.setPlainText(text)
# Create a layout for the line numbers
self.hbox = QHBoxLayout(self)
self.numbers = NumberBar(self.editor)
self.hbox.addWidget(self.numbers)
self.hbox.addWidget(self.editor)
class MyTableWidget(QWidget):
def __init__(self, parent=None):
super(QWidget, self).__init__(parent)
self.layout = QVBoxLayout(self)
# Initialize tab screen
self.tabs = TabWidget() #QTabWidget()
self.tabs.resize(300, 200)
# Add tabs
self.tabs.setTabsClosable(True)
self.tabs.tabCloseRequested.connect(self.closeTab)
# Add tabs to widget
self.layout.addWidget(self.tabs)
self.setLayout(self.layout)
def closeTab(self, index):
tab = self.tabs.widget(index)
tab.deleteLater()
self.tabs.removeTab(index)
def addtab(self, content, fileName):
self.tabs.addTab(Content(str(content)), str(fileName))
class Main(QMainWindow):
def __init__(self, parent=None):
super(Main, self).__init__(parent)
self.open()
self.tabs = MyTableWidget()
self.setCentralWidget(self.tabs)
self.initUI()
self.show()
def initUI(self):
self.statusBar()
menu = self.menuBar()
fileMenu = menu.addMenu('File')
fileMenu.addAction(self.openAct)
self.resize(800, 600)
def closeTab(self, index):
tab = self.tabs.widget(index)
tab.deleteLater()
self.tabs.removeTab(index)
def buttonClicked(self):
self.tabs.addTab(Content("smalltext2"), "sadsad")
def open(self):
self.openAct = QAction('Open...', self)
self.openAct.setShortcut('Ctrl+O')
self.openAct.setStatusTip('Open a file')
self.is_opened = False
self.openAct.triggered.connect(self.openFile)
def openFile(self):
options = QFileDialog.Options()
filenames, _ = QFileDialog.getOpenFileNames(
self, 'Open a file', '',
'Python Files (*.py);;Text Files (*.txt)',
options=options
)
if filenames:
for filename in filenames:
with open(filename, 'r+') as file_o:
try:
text = file_o.read()
self.tabs.addtab(text, filename)
except Exception as e:
print("Error: filename=`{}`, `{}` ".format( filename, str(e)))
if __name__ == '__main__':
app = QApplication(sys.argv)
ex = Main()
sys.exit(app.exec_())