Change label text from another class using Qt signals and slots - c++

Question

I'm trying to change text of a class Label from another class. I have class MainWindow, which contains Label.
I also have a Bot class from which I wanna change the value of label.
I'm trying to create signal and slots but I have no idea where to start.
I created signal and slots like so:
//in mainwindow.h
signals:
void changeTextSignal();
private slots:
void changeText();
//in mainwindow.cpp
void MainWindow::changeText(){
this->label->setText("FooBar");
}
But I have no idea how to connect a signal to be able to change Label's text from another class.

Answer 1

Read up on Qt signal-slot mechanism. If I understand you correctly, you are trying to signal from Bot to MainWindow that the Label text needs to change. Here's how you do it...
//bot.h
class Bot
{
Q_OBJECT;
//other stuff here
signals:
void textChanged(QString);
public:
void someFunctionThatChangesText(const QString& newtext)
{
emit textChanged(newtext);
}
}
//mainwindow.cpp
MainWindow::MainWindow
{
//do other stuff
this->label = new QLabel("Original Text");
mybot = new Bot; //mybot is a Bot* member of MainWindow in this example
connect(mybot, SIGNAL(textChanged(QString)), this->label, SLOT(setText(QString)));
}
void MainWindow::hello()
{
mybot->someFunctionThatChangesText("Hello World!");
}