[beginner] Displaying data from a class C++

MKUltra

Hi all,
I'm trying to create a program that displays live data from a Myo armband. I have a class DataCollector that inherits from QObject and myo::DeviceListener which collects information from the band and updates some int variables, I then just want these variables to be displayed by separate LCDNumber components in a class GUItest that inherits from QMainWindow.

What is the best way about this to go about this? I think I'm getting confused with the signals and slots.

// This is a snippet of my code:

public:
int value() const { return emgMax; }

public slots:
void setMaxValue(int value)
{
if (value != emgMax){
emgMax = value;
emit valueChanged(value);
}
}

signals:
void valueChanged(int newValue);

private:
int emgMax;

// this is the connection
connect(&collector, &DataCollector::valueChanged, ui.lcdMax, SLOT(display(int)));

// this is the call within dataCollector
if (emgSum > emgMax)
{
setMaxValue(emgSum);
}

SGaist

Hi and welcome to devnet,

// this looks wrong
connect(&collector, &DataCollector::valueChanged, ui.lcdMax, SLOT(display(int)));

connect(&collector, &DataCollector::valueChanged, ui.lcdMax, static_cast<void (QLCDNumber::*)(int)>(&QLCDNumber::display));

However are you sure that collector lives long enough ?

MKUltra

Thank you for your response. The compiler likes your connect statement.

But yes, I am now unsure about the collector's life. I have the collector as an uninitialized attribute in the class GUItest then in the constructor I handle the connection.

Where is the program flow after "return a.exec();" is reached? is there away I can just have a loop and update the lcd displays every second? As the data being collected changes in the milliseconds

SGaist

You can use a QTimer if you want to update at a fixed interval