Qt显示文本的控件很多，QLabel, QLineEdit, QPlainText等，本篇介绍QTexEdit的用法，主要API如下：

setPlainText：显示文本

toPlainText：获取文本

setHtml：设置html文本

toHtml：获取html代码

     示例代码如下：

from PyQt5.QtWidgets import *
import sys

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

    def initUI(self):
        self.setWindowTitle('QTextEdit控件演示')

        self.resize(300,320)

        self.textEdit = QTextEdit()
        self.buttonText = QPushButton('显示文本')
        self.buttonHTML = QPushButton('显示HTML')

        self.buttonToText = QPushButton('获取文本')
        self.buttonToHTML = QPushButton('获取HTML')

        layout = QVBoxLayout()
        layout.addWidget(self.textEdit)
        layout.addWidget(self.buttonText)
        layout.addWidget(self.buttonToText)
        layout.addWidget(self.buttonHTML)
        layout.addWidget(self.buttonToHTML)

        self.setLayout(layout)

        self.buttonText.clicked.connect(self.onClick_ButtonText)
        self.buttonHTML.clicked.connect(self.onClick_ButtonHTML)

        self.buttonToText.clicked.connect(self.onClick_ButtonToText)
        self.buttonToHTML.clicked.connect(self.onClick_ButtonToHTML)

    def onClick_ButtonText(self):
        self.textEdit.setPlainText('Hello World，世界你好吗？')

    def onClick_ButtonToText(self):
        print(self.textEdit.toPlainText())

    def onClick_ButtonHTML(self):
        self.textEdit.setHtml('<font color="blue" size="5">Hello World</font>')
    def onClick_ButtonToHTML(self):
        print(self.textEdit.toHtml())

if __name__ == '__main__':
    app = QApplication(sys.argv)
    main = QTextEditDemo()
    main.show()
    sys.exit(app.exec_())

       运行结果：

       QTextEdit可以多行显示，例如：