如何在PyQt5中“打印预览”由QTextDocument创建的文档？

如何解决如何在PyQt5中“打印预览”由QTextDocument创建的文档？

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()

如何在PyQt5中“打印预览”由QTextDocument创建的文档？

如何解决如何在PyQt5中“打印预览”由QTextDocument创建的文档？

解决方法

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