Trying to get a "GroupComponent" around a slider and linked label - What am I doing wrong?

8

I’m glad you got that part running.

Yes, there is. Since you create all settings and added connections in the MainComponent constructor, there is no need to have every slider as an individual object. Instead you may use an OwnedArray and stuff all LabeledSlider objects into it:

private:
    OwnedArray<LabeledSlider> knobs;

So that’s one place less to care about.
The constructor is the place, where we set things up, so that one has to be bespoke. But instead having an object as member for each parameter, we create them on the heap, and put them into our array:

MainContentComponent()
{
    LabeledSlider* control = new LabeledSlider ("Frequency");
    control->slider.setRange (20.0, 20000.0);
    control->slider.setSkewFactorFromMidPoint (500.0);
    control->slider.setNumDecimalPlacesToDisplay (1);
    control->slider.setValue(currentFrequency, dontSendNotification);
    control->slider.onValueChange = [this] { targetFrequency = frequency.slider.getValue(); };
    control->slider.setTextBoxStyle(Slider::TextBoxBelow, false, 100, 20);
    control->slider.setRange(50.0, 5000.0);
    control->slider.setSkewFactorFromMidPoint(500.0);
    control->slider.setNumDecimalPlacesToDisplay(1);
    addAndMakeVisible (knobs.add (control));

    control = new LabeledSlider ("Level");
    control->slider.setRange (0.0, 1.0);
    control->slider.onValueChange = [this] { targetLevel = (float) level.slider.getValue(); };
    addAndMakeVisible (knobs.add (control));

    // ...

And the third place, the resized, you copied your individual objects into the Array<LabeledSlider*> knobs. This is now no longer necessary, since you have the sliders in the OwedArray knobs already.
Now the circle is closed…

TBH. I never used FlexBox myself, but I think changing the items to this might help:

for (auto* k : knobs)
    knobBox.items.add(FlexItem(*k).withMinHeight(80.0f).withMinWidth(80.0f).withFlex(1).withAlignSelf (AlignSelf::autoAlign));

EDIT: just checked, and setting that value back didn’t change the behaviour back, so it might have been some other setting, I don’t know…

(Using the FlexBox demo and playing with the values there can be a big help).

Good luck