利用光标获取QTextEdit的行号

connect(pTextEdit, SIGNAL(cursorPositionChanged()), this, SLOT(on_textEdit_cursorPositionChanged()));void XXX::on_textEdit_cursorPositionChanged(){  //当前光标  QTextCursor tc = pTextEdit->textCursor();   QTextLayout *pLayout = tc.block().layout();  //当前光标在本BLOCK内的相对位置  int nCurpos = tc.position() - tc.block().position();  int nTextline = pLayout->lineForTextPosition(nCurpos).lineNumber() + tc.block().firstLineNumber();  qDebug()<<nTextline<<endl;           //可以看到行号随着光标的改变而改变}