Updating DynamicObject property in ValueTree - listeners not triggered

General JUCE discussion
1

One of my ValueTree children holds a DynamicObject property. I can update and modify this object without any problems, but doing so does not triggering any ValueTree::Listener methods. Is this a known limitation or should this work?

Maybe it’s worth mentioning that I’m modifying the object by way of a Value which is retrieved using the getPropertyAsValue() method. But this works absolutely fine for all other property types.

2

FWIW, here is some simple code demonstrating the issue. The valueTreePropertyChanged() method is never triggered, even though one of the valueTree properties is being updated?

/*******************************************************************************
 The block below describes the properties of this PIP. A PIP is a short snippet
 of code that can be read by the Projucer and used to generate a JUCE project.

 BEGIN_JUCE_PIP_METADATA

  name:             MyComponentPIP

  dependencies:     juce_core, juce_data_structures, juce_events, juce_graphics, juce_gui_basics
  exporters:        XCODE_MAC

  moduleFlags:      JUCE_STRICT_REFCOUNTEDPOINTER=1

  type:             Component
  mainClass:        MyComponent

 END_JUCE_PIP_METADATA

*******************************************************************************/

#pragma once


//==============================================================================
class MyComponent  : public juce::Component, public ValueTree::Listener
{
public:
    //==============================================================================
    MyComponent(): valueTree("testValueTree")
    {
        setSize (600, 400);
        valueTree.addListener(this);
        juce::ValueTree child("child");
        child.setProperty("DyObj", new juce::DynamicObject(), nullptr);
        valueTree.addChild(child, -1, nullptr);
        auto childNode = valueTree.getChild(0);
        //update/change the object
        childNode.getProperty("DyObj").getDynamicObject()->setProperty("NewData", "a string");
    }

    ~MyComponent() override   {}

    void valueTreeChildAdded (juce::ValueTree& parentVt, juce::ValueTree& newVt)
    {
        DBG(newVt.getType().toString());
        
    }
    void valueTreePropertyChanged(juce::ValueTree& vt, const juce::Identifier& prop)
    {
        DBG(prop);
    }
    
    //==============================================================================
    void paint (juce::Graphics& g) override   {}

    void resized() override {}

    //ValueTree::Listener virtual methods....

    void valueTreeChildRemoved (juce::ValueTree&, juce::ValueTree&, int) override {}
    void valueTreeChildOrderChanged (juce::ValueTree&, int, int) override {}
    void valueTreeParentChanged (juce::ValueTree&) override {}
    

private:
    //==============================================================================
    // Your private member variables go here...
    ValueTree valueTree;

    JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (MyComponent)
};
3

I’ve run into this as well. You only get a callback if you change to a different DynamicObject. You do not get callback if you change the properties within the DynamicObject.

You could just call sendPropertyChangeMessage manually.

Matt

1 Like
4

Thanks @matt :+1: I’m not sure how I missed that sendPropertyChangeMessage() method :see_no_evil: That will do the trick nicely.

5

Close, but no cigar just yet. If I call getPropertyAsValue() and assign to a value, and then call that value’s getValueSource().sendChangeMessage(true); it once again fails to trigger any ValueTree listeners:

        juce::ValueTree child("child");
        juce::var obj = new juce::DynamicObject();
        child.setProperty("DyObj", obj, nullptr);
        valueTree.addChild(child, -1, nullptr);
        auto childNode = valueTree.getChild(0);
        childNode.addListener(this);
        
        childNode.getProperty("DyObj").getDynamicObject()->setProperty("NewData", "a string");
        value = childNode.getPropertyAsValue("DyObj", nullptr);
        value.getValue().getDynamicObject()->setProperty("MoreNewData", "a string");
        
        //this doesn't trigger..
        value.getValueSource().sendChangeMessage(true);
        
        //this triggers..
        //childNode.sendPropertyChangeMessage("DyObj");

I can always pass the entire ValueTree to my property component, but I’d like to know if this is expected behaviour or is something broken somewhere?

6

Try childNode.sendPropertyChangeMessage(“DyObj”).

Calling value.getValueSource().sendChangeMessage(true) will generate callbacks to Value::Listener::valueChanged, not ValueTree::Listener::valueTreePropertyChanged.

Matt

7

Yes, I had that marked in my code as working fine. Thanks for the full break down. It’s clear how I can work with this now, and I’m happy to say everything is now working as it should be. Thanks again :+1:

8

Yes, I had that marked in my code as working fine.
Right, so you did; I missed that. Glad you’ve got it all sorted out.

Matt

1 Like
9

I just came across the ValueTreePropertyWithDefault class. Seems like this might be a better choice for me in this instance. :+1: