Safe way to remove Parameter Listeners

[davispolito]

Is there a safe way to remove parameter Listeners? Like adding some sort of tag to the function? I am doing dynamic popup windows for the sliders but it seems as though the parameterListeners stick around even when the old sliders are deleted. Not 100% sure that this is what is happening yet but it looks like it

[davispolito]

My current workaround is to just simply not delete the c PopupComponent which holds a ParameterView once it's been created once. This fixes it. But I worry about memory whenever there are large numbers of objects that have been opened and closed and we don't care about them at any given moment they aren't on

[jatinchowdhury18]

Usually I make a parameter listener by doing something like:

callback = pluginState.addParameterListener (...);

where callback is a chowdsp::ScopedCallback. The parameter listener will effectively be "deleted" when the callback is deleted. Usually, the simplest way to do this in your UI code is to have the callback object be a member variable in your Component class, so that the listener is deleted when the component is deleted. For example:

class MyComponent : public juce::Component
{
    chowdsp::ScopedCallback callback;

    MyComponent (chowdsp::PluginState& state)
    {
        callback = state.addParameterListener (...);
    }
    ~MyComponent() override = default; // the listener is deleted here!
};

If you need more granular control, you could store the callback in a std::optional<chowdsp::ScopedCallback> and manually reset() the optional when you want to delete the callback. Or if you have a bunch of them, it might be better to have a std::vector<chowdsp::ScopedCallback> and add/remove listeners from the vector as they are created/deleted.