How to check two QLineEdit If they are not empty - c++

Question

I have three controls, two QTextLine and one QPushButton.
When startup the program, the add button will be disabled, and must be two QTextLine not empty for enable the add button.
I have the following code, but it does not works fine:
void Question_Answer::on_newQuestion_txt_textChanged(const QString &arg1)
{
if(arg1.isEmpty())
{
ui->addNewQuestion_btn->setEnabled(false);
}
else
{
ui->addNewQuestion_btn->setEnabled(true);
}
}
void Question_Answer::on_newAnswer_txt_textChanged(const QString &arg1)
{
if(ui->newAnswer_txt->text().isEmpty())
{
ui->addNewQuestion_btn->setEnabled(false);
}
else
{
ui->addNewQuestion_btn->setEnabled(true);
}
}
Now, How to check if the two QTextLine are not empty, and also if any of them is empty, how to disable the add button.

Answer 1

Just connect a single slot to handle textChanged signals of both LineEdits
void Question_Answer::onTextChanged(const QString &arg1){
if(ui->newAnswer_txt->text().isEmpty() || ui->newQuestion_txt->text().isEmpty()){
ui->addNewQuestion_btn->setEnabled(false);
}else{
ui->addNewQuestion_btn->setEnabled(true);
}
}

Answer 2

In the header class:
// ...
private slots:
void onTextChanged();
// ...
In the source file:
// Setup the connections in the constructor.
void Question_Answer::onTextChanged()
{
const bool editable1 = ui->newAnswer_txt->text().size() > 0;
const bool editable2 = ui->newQuestion_txt->text().size() > 0;
ui->addNewQuestion_btn->setEnabled( editable1 && editable2 );
}