# Python PyQt6 Module

PyQt6 is a set of Python bindings for the Qt application framework. It allows you to create modern, professional, and cross-platform desktop applications.

## Installation

```bash
pip install PyQt6
```

## Basic Application

Every PyQt6 application must create an application object (`QApplication`).

```python
import sys
from PyQt6.QtWidgets import QApplication, QWidget

# 1. Create the Application
app = QApplication(sys.argv)

# 2. Create the main window (QWidget is the base class of all UI objects)
window = QWidget()
window.setWindowTitle("PyQt6 App")
window.resize(400, 300)

# 3. Show the window
window.show()

# 4. Start the event loop
sys.exit(app.exec())
```

## Main Window (`QMainWindow`)

For a standard application window with a menu bar, toolbars, and a status bar, use `QMainWindow`.

```python
from PyQt6.QtWidgets import QApplication, QMainWindow, QLabel

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("My App")
        
        label = QLabel("Hello World!")
        # Set the central widget of the Window
        self.setCentralWidget(label)

app = QApplication([])
window = MainWindow()
window.show()
app.exec()
```

## Layouts

Layouts manage the positioning of widgets automatically.

*   `QVBoxLayout`: Vertical arrangement.
*   `QHBoxLayout`: Horizontal arrangement.
*   `QGridLayout`: Grid arrangement.

```python
from PyQt6.QtWidgets import QWidget, QVBoxLayout, QPushButton

window = QWidget()
layout = QVBoxLayout()

layout.addWidget(QPushButton("Top"))
layout.addWidget(QPushButton("Center"))
layout.addWidget(QPushButton("Bottom"))

window.setLayout(layout)
window.show()
```

## Signals and Slots

Qt uses a mechanism called signals and slots for event handling. A **signal** is emitted when a particular event occurs. A **slot** is a function that is called in response to a particular signal.

```python
from PyQt6.QtWidgets import QApplication, QPushButton

def on_button_clicked():
    print("Button was clicked!")

app = QApplication([])
button = QPushButton("Click Me")

# Connect the signal to the slot
button.clicked.connect(on_button_clicked)

button.show()
app.exec()
```

[[programming/python/python]]