QTextEdit的使用

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QTextEdit,QVBoxLayout, QPushButton

class TextEditDemo(QWidget):

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

        self.setWindowTitle("QTextEdit例子")
        self.resize(300, 270)
        self.textEdit = QTextEdit()
        self.btnPress1 = QPushButton("显示文本")
        self.btnPress2 = QPushButton("显示html")

        layout= QVBoxLayout()
        layout.addWidget(self.textEdit)
        layout.addWidget(self.btnPress1)
        layout.addWidget(self.btnPress2)

        self.setLayout(layout)
        self.btnPress1.clicked.connect(self.btnPress1_Clicked)
        self.btnPress2.clicked.connect(self.btnPress2_Clicked)


    def btnPress1_Clicked(self):
        self.textEdit.setPlainText("Hello PyQt5!
单击按钮")

    def btnPress2_Clicked(self):
        self.textEdit.setHtml("<font color='red' size='6'><red>Hello PyQt5!
 单击按钮。</font>")

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

效果如图：