QTextEdit

（1）insertPlainText
//insertPlainText插入数据到文字的后方
ui->textEdit ->insertPlainText(QString);
（2）setText
ui->textEdit_Reca->setText();
（3）显示可见
QScrollBar *scro = ui->textEdit_Reca->verticalScrollBar();
scro->setSliderPosition(scro->maximum());
（4）只读
ui->textEdit_Reca->setReadOnly(true); //不可编辑