Make every tab the same width and also expandable

Question

I'm trying to achieve something like the tabs from a Browser. All tabs must have the same width and also be expandable so when there are a lot of them they need to resize and fit the window (exactly like Chrome or Firefox does).

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The Problem:

If a tab have more text then the other tabs, the tab will be larger. Like so:

And if I spawn a lot of tabs, it will always be larger then the others.

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What I have tried:

I have tried to add a stylesheet to change the width, but if I change the width to a specific number, the tabs will be static and not resize based on the number of tabs to fit the window. Also I tried to tweak with min/max width, messing with the QSizePolicy, but no chance.

I have looked at the documentation of QT5 for C++ and googled a lot, but no place talks about this or any option about this.

Maybe I need to do some calculations in python and add to a stylesheet as a argument, but not sure how. Maybe there is a simple option that I'm missing.

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My code: (This is the full code, so you can copy-paste and test it if you need)

import sys

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QTabWidget,\
    QVBoxLayout, QHBoxLayout, QSizePolicy


class Container(QWidget):
    def __init__(self, text):
        super(Container, self).__init__()

        self.hbox = QHBoxLayout()
        self.hbox.setSpacing(0)
        self.hbox.setContentsMargins(0, 0, 0, 0)
        self.setLayout(self.hbox)

        self.button = QPushButton(text)
        self.hbox.addWidget(self.button)


class CustomWidget (QWidget):
    def __init__(self, parent=None):
        super(CustomWidget, self).__init__(parent)

        self.button = QPushButton("Add tab")
        self.button.clicked.connect(self.buttonClicked)

        self.tabs = QTabWidget()
        self.tabs.setTabsClosable(True)
        self.tabs.setMovable(True)
        self.tabs.setDocumentMode(True)
        self.tabs.setElideMode(Qt.ElideRight)
        self.tabs.setUsesScrollButtons(True)
        self.tabs.tabCloseRequested.connect(self.closeTab)

        self.tabs.addTab(Container("Very big titleeeeeeeeee"),
                         "Very big titleeeeeeeeeeee")
        self.tabs.addTab(Container("smalltext"), "smalltext")
        self.tabs.addTab(Container("smalltext2"), "smalltext2")

        vbox = QVBoxLayout()
        vbox.addWidget(self.button)
        vbox.addWidget(self.tabs)
        self.setLayout(vbox)

        self.resize(600, 600)

    def closeTab(self, index):
        tab = self.tabs.widget(index)
        tab.deleteLater()
        self.tabs.removeTab(index)

    def buttonClicked(self):
        self.tabs.addTab(Container("smalltext2"), "smalltext2")


app = QApplication([])

app.setStyleSheet("""
    QTabBar::tab {
        background: lightgray;
        color: black;
        border: 0;
        /* min-width: 100px; */
        max-width: 200px;
        /* width: 150px; */
        height: 20px;
        padding: 5px;
    }

    QTabBar::tab:selected {
        background: gray;
        color: white;
    }
""")

widget = CustomWidget()
widget.show()

sys.exit(app.exec_())

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Other information:

Operating System: Windows 10
Python Version: 3.6.2
PyQt Version: 5.9.1

Answer 1

To set the width for all tabs we must override the tabSizeHint() method, in this case we return the same width for all tabs.

class TabBar(QTabBar):
    def tabSizeHint(self, index):
        size = QTabBar.tabSizeHint(self, index)
        w = int(self.width()/self.count())
        return QSize(w, size.height())

After assigning this custom tabBar we use the setTabBar() method of QTabWidget.

self.tabs = QTabWidget()
self.tabs.setTabBar(TabBar())

Output:

The example can be found in the following link