[Python practical foundation] Drag and drop button component of PyQt6 in Python

Table of contents

1. The actual combat scene

2. Main points of knowledge

file read and write

Basic grammar

PyQt6

sys

Three, rookie combat

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1. The actual combat scene

Practical scenario: Drag-and-drop button component of PyQt6 in Python

2. Main points of knowledge

• file read and write

• Basic grammar

• PyQt6

• sys

Three, rookie combat

Create a file!

import sys

from PyQt6.QtCore import Qt, QMimeData
from PyQt6.QtGui import QDrag
from PyQt6.QtWidgets import QPushButton, QWidget, QApplication


class Button(QPushButton):

    def __init__(self, title, parent):
        super().__init__(title, parent)


    def mouseMoveEvent(self, e):

        if e.buttons() != Qt.MouseButtons.RightButton:
            return

        mimeData = QMimeData()

        drag = QDrag(self)
        drag.setMimeData(mimeData)

        drag.setHotSpot(e.position().toPoint() - self.rect().topLeft())

        dropAction = drag.exec(Qt.DropActions.MoveAction)


    def mousePressEvent(self, e):

        super().mousePressEvent(e)

        if e.button() == Qt.MouseButtons.LeftButton:
            print('press')


class Example(QWidget):

    def __init__(self):
        super().__init__()

        self.initUI()


    def initUI(self):

        self.setAcceptDrops(True)

        self.button = Button('Button', self)
        self.button.move(100, 65)

        self.setWindowTitle('Click or Move')
        self.setGeometry(300, 300, 550, 450)


    def dragEnterEvent(self, e):

        e.accept()


    def dropEvent(self, e):

        position = e.position()
        self.button.move(position.toPoint())

        e.setDropAction(Qt.DropActions.MoveAction)
        e.accept()


def main():

    app = QApplication(sys.argv)
    ex = Example()
    ex.show()
    app.exec()


if __name__ == '__main__':
    main()

In this example, there is one in the window.  QPushButtonClicking on it with the left mouse button will print a 'press' message to the console, and you can click and drag it with the right mouse button.

class Button(QPushButton):

    def __init__(self, title, parent):
        super().__init__(title, parent)

QPushButton Created a  class based on  Button and implemented two  QPushButton methods: mouseMoveEvent and  mousePressEvent. mouseMoveEvent The method is where the handling of the drag and drop operation begins.

if e.buttons() != Qt.MouseButtons.RightButton:
    return

Define the right mouse button as the button that triggers the drag operation, and the left mouse button will only trigger the click event.

drag = QDrag(self)
drag.setMimeData(mimeData)

drag.setHotSpot(e.position().toPoint() - self.rect().topLeft())

Create  QDrag objects to provide drag and drop operations based on MIME data types.

dropAction = drag.exec(Qt.DropActions.MoveAction)

drag The methods of the object  exec perform the drag and drop operation.

def mousePressEvent(self, e):

    super().mousePressEvent(e)

    if e.button() == Qt.MouseButtons.LeftButton:
        print('press')

If the button is clicked with the left mouse button, the 'press' message will be printed on the console. Note that the  mousePressEvent method is also called on the parent here, otherwise the button press action will not be displayed.

position = e.pos() self.button.move(position) 

dropEvent The method handles the operation after the mouse releases the button - modify the position of the component to the current coordinates of the mouse.

e.setDropAction(Qt.MoveAction) e.accept() 

Use the  setDropAction specified type of drag-and-drop operation -- mouse movement.

​Rookie combat, keep learning!