How Do I Save and Load Data Using QSettings? - c++

Question

I'm a complete beginner to QT5, I searched YouTube for any QSettings tutorials and only found 2 of them, both in Spanish.
I'm trying to store simple text from a textEdit and then load it on save/load button click. So far I have not been able to accomplish this. Here's my code so far, no errors, it just doesn't work.
Widget.cpp
void Widget::saveText(QString key, QString text)
{
QSettings settings("App", "BillReminder");
settings.beginGroup("Text");
settings.setValue(key + "t", text);
settings.endGroup();
}
QString Widget::loadText(QString key)
{
QSettings settings("App", "BillReminder");
settings.beginGroup("Text");
settings.value(key + "t", text).toString();
settings.endGroup();
return QString(text);
}
void Widget::on_saveButton_clicked()
{
saveText("textEdit", text);
}
void Widget::on_loadButton_clicked()
{
QString text1 = loadText(text);
ui->textEdit->setText(text1);
}
widget.h - class Widget : public QWidget
private:
Ui::Widget *ui;
QString text;
void saveText(QString key, QString text);
QString loadText(QString key);
void SetText(QString key);

Answer 1

The problem is in your loadText() method. QSettings::value() is a function that returns a value retrieved from the QSettings storage. The second parameter is only a default value, that would be returned in case your settings storage doesn't contain the requested key.
QString Widget::loadText(QString key)
{
QSettings settings("App", "BillReminder");
settings.beginGroup("Text");
QString theValue = settings.value(key + "t", text).toString();
settings.endGroup();
return theValue;
}

Answer 2

This code example contains many issues.
don't shadow variable names (e.g. "text" is method argument and member variable); use e.g. underscore to indicate member variables
above answer about reading values as return value solve one issue as well
on_saveButton is using as a settings key a "textEdit" string but on_loadButton is used wrong "text" member variable string as key -> you want use the same string to load stored variable i.e. you are reading something else just now.
you are saving member variable "text" that is not initialised in your example i.e. it may be empty; and later you are setting UI text edit with stored settings (empty string in your example?)
Please go through QSettings Qt documentation for working example.