Pyqt5 rapid development and practice 4.11 drag and clipboard

PyQt5 Rapid development and actual combat

4. The first 4 Chapter PyQt5 Basic window control

4.11 Drag and clipboard

4.11.1 Drag And Drop

The drag function provided for users is very intuitive , In many desktop applications , Copying or moving objects can be done by dragging .
be based on MIME The type of drag data transfer is based on QDrag Class .QMimeData Object to associate the associated data with its corresponding MIME Associated with type .

MIME： Multipurpose Internet mail extension type . A file with an extension is a type of file opened by an application , When the extension file is accessed , The browser will automatically use the specified application to open , Mostly used to specify some client-side customized file names , And some ways to open media files .

MIME Types of data can be simply understood as various resources on the Internet , For example, the text 、 Audio and video resources , Every resource on the Internet belongs to one MIME Data of type .

MimeData Class functions allow easy detection and use of MIME type

Judgment function	Set function	Get function	MIME type
hasText()	text()	setText()	text/plain
hasHtml()	html()	setHtml()	text/html
hasUrls()	urls()	setUrls()	text/uri-list
hasImage()	imageData()	setImageData()	image/*
hasColor()	colorData()	setColorData()	application/x-color

many QWidget All objects support drag action , Controls that allow dragging data must be set to QWidget.setDragEnabled() by True. in addition , Control should respond to drag events , To store the dragged data .

Common drag events

event	describe
DragEnterEvent	When performing a drag control operation , And when the mouse pointer enters the control , This event will be triggered . In this event, you can get the operated window control , The drag operation can also be conditionally accepted or rejected
DragMoveEvent	This event will be triggered when the drag operation is in progress
DragLeaveEvent	When performing a drag control operation , And when the mouse pointer leaves the control , This event will be triggered
DropEvent	When the drag operation is released on the target control , This event will be triggered

Drag function —— Case study

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class Combo(QComboBox):
    def __init__(self , title , parent):
        super(Combo, self).__init__(parent)
        self.setAcceptDrops(True)

    def dragEnterEvent(self , e):
        print(e)
        if e.mimeData().hasText():
            e.accept()
        else:
            e.ignore()

    def dropEvent(self,e):
        self.addItem(e.mimeData().text())

class Example(QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.initUI()

    def initUI(self):
        lo = QFormLayout()
        lo.addRow(QLabel(" Please drag the text on the left to the drop-down menu on the right "))
        edit = QLineEdit()
        edit.setDragEnabled(True)
        com = Combo("Button",self)
        lo.addRow(edit , com)
        self.setLayout(lo)
        self.setWindowTitle(" drag —— Example ")


if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = Example()
    win.show()
    sys.exit(app.exec_())

4.11.2 QClipboard

QClipboard Class provides access to the system clipboard , You can copy and paste data between applications . It operates like QDrag class , And use similar data types .

QApplication Class has a static method clipboard(), It returns a reference to the clipboard object . Of any kind MimeData Can be copied or pasted from the clipboard .

QClipboard Common methods in class

Method	describe
clear()	Clear the contents of the clipboard
setImage()	take QImage Object is copied to the clipboard
setMimeData()	take MIME Data set to clipboard
setPixmap()	Copy from clipboard Pixmap object
setText()	Copy text from clipboard
text()	Retrieve text from clipboard

QClipboard Class

The signal	meaning
dataChanged	When the clipboard contents change , This signal is transmitted

QClipboard Use —— Case study

import os
import sys
from PyQt5.QtCore import QMimeData
from PyQt5.QtWidgets import (QApplication,QDialog,QGridLayout,QLabel,QPushButton)
from PyQt5.QtGui import QPixmap


class Form(QDialog):
    def __init__(self, parent=None):
        super(Form, self).__init__(parent)
        textCopyButton = QPushButton("&Copy Text")
        textPasteButton = QPushButton("Paste &Text")
        htmlCopyButton = QPushButton("C&opy HTML")
        htmlPasteButton = QPushButton("Paste &HTML")
        imageCopyButton = QPushButton("Co&py Image")
        imagePasteButton = QPushButton("Paste &Image")
        self.textLabel = QLabel("Original text")
        self.imageLabel = QLabel()
        self.imageLabel.setPixmap(QPixmap(os.path.join(
            os.path.dirname(__file__), "images/clock.png")))
        layout = QGridLayout()
        layout.addWidget(textCopyButton, 0, 0)
        layout.addWidget(imageCopyButton, 0, 1)
        layout.addWidget(htmlCopyButton, 0, 2)
        layout.addWidget(textPasteButton, 1, 0)
        layout.addWidget(imagePasteButton, 1, 1)
        layout.addWidget(htmlPasteButton, 1, 2)
        layout.addWidget(self.textLabel, 2, 0, 1, 2)
        layout.addWidget(self.imageLabel, 2, 2)
        self.setLayout(layout)
        textCopyButton.clicked.connect(self.copyText)
        textPasteButton.clicked.connect(self.pasteText)
        htmlCopyButton.clicked.connect(self.copyHtml)
        htmlPasteButton.clicked.connect(self.pasteHtml)
        imageCopyButton.clicked.connect(self.copyImage)
        imagePasteButton.clicked.connect(self.pasteImage)
        self.setWindowTitle("Clipboard  Example ")

    def copyText(self):
        clipboard = QApplication.clipboard()
        clipboard.setText(" I was copied !")

    def pasteText(self):
        clipboard = QApplication.clipboard()
        self.textLabel.setText(clipboard.text())

    def copyImage(self):
        clipboard = QApplication.clipboard()
        clipboard.setPixmap(QPixmap(os.path.join(
            os.path.dirname(__file__), "../ Package resource files /pic/python.jpg")))

    def pasteImage(self):
        clipboard = QApplication.clipboard()
        self.imageLabel.setPixmap(clipboard.pixmap())

    def copyHtml(self):
        mimeData = QMimeData()
        mimeData.setHtml("<b>Bold and <font color=red>Red</font></b>")
        clipboard = QApplication.clipboard()
        clipboard.setMimeData(mimeData)

    def pasteHtml(self):
        clipboard = QApplication.clipboard()
        mimeData = clipboard.mimeData()
        if mimeData.hasHtml():
            self.textLabel.setText(mimeData.html())


if __name__ == '__main__':
    from pyqt5_plugins.examples.exampleqmlitem import QtCore
    QtCore.QCoreApplication.setAttribute(QtCore.Qt.AA_EnableHighDpiScaling)
    app = QApplication(sys.argv)
    win = Form()
    win.show()
    sys.exit(app.exec_())