如何在PyQt5中“打印预览”由QTextDocument创建的文档？

编程问答 2022-06-13

问题描述

您好专家！！希望您过得愉快。我是GUI编程的新手，尤其是PyQt5。我正在练习简单的GUI发票应用程序。在此应用程序中，我成功地通过QTextDocument生成了发票。现在，我想添加打印对话框和打印预览选项。我在代码中遇到麻烦。这是在说

AttributeError：'InvoiceForm'对象没有属性 'printpreviewDialog

由于我是新人，所以我有点困惑。您能解决代码吗？这对我的学习很有帮助。非常感谢。 代码如下：-

import sys
from PyQt5.QtCore import pyqtSignal,QSize,QSizeF,QDate
from PyQt5.QtGui import QTextDocument,QTextCursor,QFont
from PyQt5.QtPrintSupport import QPrinter,QPrintPreviewDialog
from PyQt5.QtWidgets import QWidget,QFormLayout,QLineEdit,QPlainTextEdit,QSpinBox,QDateEdit,QTableWidget,\
    QHeaderView,QPushButton,QHBoxLayout,QTextEdit,QApplication,QMainWindow

font= QFont('Arial',16)

class InvoiceForm(QWidget):
    submitted = pyqtSignal(dict)
    def __init__(self):
        super().__init__()
        self.setLayout(QFormLayout())
        self.inputs = dict()
        self.inputs['Customer Name'] = QLineEdit()
        self.inputs['Customer Address'] = QPlainTextEdit()
        self.inputs['Invoice Date'] = QDateEdit(date=QDate.currentDate(),calendarPopup=True)
        self.inputs['Days until Due'] = QSpinBox()
        for label,widget in self.inputs.items():
            self.layout().addRow(label,widget)

        self.line_items = QTableWidget(rowCount=10,columnCount=3)
        self.line_items.setHorizontalHeaderLabels(['Job','Rate','Hours'])
        self.line_items.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch)
        self.layout().addRow(self.line_items)
        for row in range(self.line_items.rowCount()):
            for col in range(self.line_items.columnCount()):
                if col > 0:
                    w = QSpinBox()
                    self.line_items.setCellWidget(row,col,w)

        submit = QPushButton('Create Invoice',clicked=self.on_submit)
        print = QPushButton('Print Invoice',clicked=self.printpreviewDialog)
        self.layout().addRow(submit,print)

    def on_submit(self):
        data = {'c_name': self.inputs['Customer Name'].text(),'c_addr': self.inputs['Customer Address'].toPlainText(),'i_date': self.inputs['Invoice Date'].date().toString(),'i_due': self.inputs['Invoice Date'].date().addDays(self.inputs['Days until Due'].value()).toString(),'i_terms': '{} days'.format(self.inputs['Days until Due'].value()),'line_items': list()}

        for row in range(self.line_items.rowCount()):
            if not self.line_items.item(row,0):
                continue
            job = self.line_items.item(row,0).text()
            rate = self.line_items.cellWidget(row,1).value()
            hours = self.line_items.cellWidget(row,2).value()
            total = rate * hours
            row_data = [job,rate,hours,total]
            if any(row_data):
                data['line_items'].append(row_data)

        data['total_due'] = sum(x[3] for x in data['line_items'])
        self.submitted.emit(data)
        # remove everything else in this function below this point

class InvoiceView(QTextEdit):
    dpi = 72
    doc_width = 8.5 * dpi
    doc_height = 6 * dpi

    def __init__(self):
        super().__init__(readOnly=True)
        self.setFixedSize(QSize(self.doc_width,self.doc_height))

    def build_invoice(self,data):
        document = QTextDocument()
        self.setDocument(document)
        document.setPageSize(QSizeF(self.doc_width,self.doc_height))
        document.setDefaultFont(font)
        cursor = QTextCursor(document)
        cursor.insertText(f"Customer Name: {data['c_name']}\n")
        cursor.insertText(f"Customer Address: {data['c_addr']}\n")
        cursor.insertText(f"Date: {data['i_date']}\n")
        cursor.insertText(f"Total Due: {data['total_due']}\n")

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        central = QWidget()
        self.setCentralWidget(central)
        layout = QHBoxLayout(central)

        self.invoiceForm = InvoiceForm()
        layout.addWidget(self.invoiceForm)

        self.invoiceView = InvoiceView()
        layout.addWidget(self.invoiceView)
        # hide the widget right now...
        self.invoiceView.setVisible(False)

        self.invoiceForm.submitted.connect(self.showPreview)

    def showPreview(self,data):
        self.invoiceView.setVisible(True)
        self.invoiceView.build_invoice(data)

    def printpreviewDialog(self):
        printer = QPrinter(QPrinter.HighResolution)
        previewDialog = QPrintPreviewDialog(printer,self)
        previewDialog.paintRequested.connect(self.printPreview)
        previewDialog.exec_()

    def printPreview(self,printer):
        self.invoiceView.build_invoice.print_(printer)

def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    app.exec_()

if __name__ == '__main__':
    main()

解决方法

主要问题是self.printpreviewDialog是MainWindow的成员，而不是InvoiceForm的成员，因此您应该从主窗口连接clicked信号。

还请注意，您尝试使用self.invoiceView.build_invoice.print_()，但是由于您不是调用 build_invoice，因此无法使用，即使您使用了该功能，该功能也不会不退还任何东西。

您应该改用self.invoiceView.document()，但必须确保之前已建立数据。

class InvoiceForm(QWidget):
    submitted = pyqtSignal(dict)
    def __init__(self):
        # ...
        submit = QPushButton('Create Invoice',clicked=self.on_submit)
        # make the button a member of the instance instead of a local variable,# so that we can connect from the main window instance
        self.printButton = QPushButton('Print Invoice')
        self.layout().addRow(submit,self.printButton)

# ...

class MainWindow(QMainWindow):
    def __init__(self):
        # ...
        self.invoiceForm.printButton.clicked.connect(self.printpreviewDialog)
    # ...

    def printPreview(self,printer):
        self.invoiceView.document().print_(printer)

注意：从不，从不使用变量的内置函数和语句，例如print。

,

尝试一下：

import sys
from PyQt5.QtCore import pyqtSignal,QSize,QSizeF,QDate
from PyQt5.QtGui import QTextDocument,QTextCursor,QFont
from PyQt5.QtPrintSupport import QPrinter,QPrintPreviewDialog
from PyQt5.QtWidgets import (QWidget,QFormLayout,QLineEdit,QPlainTextEdit,QSpinBox,QDateEdit,QTableWidget,QHeaderView,QPushButton,QHBoxLayout,QTextEdit,QApplication,QMainWindow)


font = QFont('Arial',16)


class InvoiceForm(QWidget):
    submitted = pyqtSignal(dict)
    
    def __init__(self,parent=None):                                        # + parent=None
        super().__init__(parent)                                            # + parent
        self.setLayout(QFormLayout())
        self.inputs = dict()
        self.inputs['Customer Name'] = QLineEdit()
        self.inputs['Customer Address'] = QPlainTextEdit()
        self.inputs['Invoice Date'] = QDateEdit(date=QDate.currentDate(),calendarPopup=True)
        self.inputs['Days until Due'] = QSpinBox()
        for label,widget in self.inputs.items():
            self.layout().addRow(label,widget)

        self.line_items = QTableWidget(rowCount=10,columnCount=3)
        self.line_items.setHorizontalHeaderLabels(['Job','Rate','Hours'])
        self.line_items.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch)
        self.layout().addRow(self.line_items)
        for row in range(self.line_items.rowCount()):
            for col in range(self.line_items.columnCount()):
                if col > 0:
                    w = QSpinBox()
                    self.line_items.setCellWidget(row,col,w)

        submit = QPushButton('Create Invoice',clicked=self.on_submit)
        
# +     vvvvvv                                        vvvvvvvvvvvvv 
        _print = QPushButton('Print Invoice',clicked=self.window().printpreviewDialog)  # + _print,+ self.window()
        self.layout().addRow(submit,_print)                                             # + _print

    def on_submit(self):
        data = {'c_name': self.inputs['Customer Name'].text(),'c_addr': self.inputs['Customer Address'].toPlainText(),'i_date': self.inputs['Invoice Date'].date().toString(),'i_due': self.inputs['Invoice Date'].date().addDays(self.inputs['Days until Due'].value()).toString(),'i_terms': '{} days'.format(self.inputs['Days until Due'].value()),'line_items': list()}

        for row in range(self.line_items.rowCount()):
            if not self.line_items.item(row,0):
                continue
            job = self.line_items.item(row,0).text()
            rate = self.line_items.cellWidget(row,1).value()
            hours = self.line_items.cellWidget(row,2).value()
            total = rate * hours
            row_data = [job,rate,hours,total]
            if any(row_data):
                data['line_items'].append(row_data)

        data['total_due'] = sum(x[3] for x in data['line_items'])
        self.submitted.emit(data)
        # remove everything else in this function below this point
# +
        return data                                                            # +++
        

class InvoiceView(QTextEdit):
    dpi = 72
    doc_width = 8.5 * dpi
    doc_height = 6 * dpi

    def __init__(self):
        super().__init__(readOnly=True)
        self.setFixedSize(QSize(self.doc_width,self.doc_height))

    def build_invoice(self,data):
        document = QTextDocument()
        self.setDocument(document)
        document.setPageSize(QSizeF(self.doc_width,self.doc_height))
        document.setDefaultFont(font)
        cursor = QTextCursor(document)
        cursor.insertText(f"Customer Name: {data['c_name']}\n")
        cursor.insertText(f"Customer Address: {data['c_addr']}\n")
        cursor.insertText(f"Date: {data['i_date']}\n")
        cursor.insertText(f"Total Due: {data['total_due']}\n")
# +        
        return document                                                         # +++
        

class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        central = QWidget()
        self.setCentralWidget(central)
        layout = QHBoxLayout(central)
# +                                    vvvv
        self.invoiceForm = InvoiceForm(self)                                    # + self
        
        layout.addWidget(self.invoiceForm)
        self.invoiceView = InvoiceView()
        layout.addWidget(self.invoiceView)
        # hide the widget right now...
        self.invoiceView.setVisible(False)
        self.invoiceForm.submitted.connect(self.showPreview)

    def showPreview(self,data):
        self.invoiceView.setVisible(True)
        self.invoiceView.build_invoice(data)

# +++ vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    def printpreviewDialog(self):
        previewDialog = QPrintPreviewDialog()
        previewDialog.paintRequested.connect(self.printPreview)  
        previewDialog.exec_()

    def printPreview(self,printer):
#        self.invoiceView.build_invoice.print_(printer)        
        data = self.invoiceForm.on_submit()
        document = self.invoiceView.build_invoice(data)
        document.print_(printer)
# +++ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


def main():
    app = QApplication(sys.argv)
    window = MainWindow()
    window.show()
    app.exec_()

if __name__ == '__main__':
    main()

enter image description here

print-previewprintingpyqt5pythonqtextdocument

相关问答

matplotlib报错：AttributeError: module 'backend_interagg' has no attribute 'FigureCanvas'. Did you mean: 'FigureCanvasAgg'?
使用本地python环境可以成功执行 import pandas as pd impor...
gitlab登录失败，报错：This challenge page was accidentally cached by an intermediary and is no longer available.
设置时间 控制面板
后端开发常见错误
错误1：Request method ‘DELETE‘ not supported 错误还原：...
docker常见错误
错误1：启动docker镜像时报错：Error response from daemon:...
idea常见错误
错误1：private field ‘xxx‘ is never assigned 按Alt...
pip安装依赖失败
报错如下，通过源不能下载，最后警告pip需升级版本 Requirem...