OnChanged_ Function Callback
OnChanged_ function binding is a function definition pattern whıch can be called when a specific variable or array index is changed on RealityHub. The OnChanged_FunctionName (with underscore) pattern triggers any node-base mechanism when the property has changed on run-time. You can also bind OnChanged_ function binding for arrays returns the index of changed property on Reality API. The changed index on the Reality API executes the blueprint function with the changed index number.
- 1.The variable and function you want to expose must be declared as Public. (instance editable).
- 2.The function created on the event-graph must follow this format: OnChanged_AnyVariableName (The underscore character after OnChanged is required).
- 3.After OnChanged_, the function name must be the same as the variable name.
- 4.The developer must take care of Case Sensitive for functions.
- 5.If you bind your array for the OnChanged_ pattern, only one integer parameter must be aware of the changed index.
Functions and variables must be "Public," and function names are Case Sensitive.
- Create a new Actor class object. Click ADD NEW on Components tab. Add ZD ACTOR.

- Create a new variable named MyVariable with the variable type of Integer. Make it public(instance editable).

- Create a new function. Change name of the function as OnChanged_MyVariable

The function name must follow this pattern OnChanged_VariableName
- On the graph, switch the MyVariable and print string regarding values. After complete, the graph, click on the COMPILE and then the SAVE.

- Put your actor to the level.
- Launch Reality Setup.
- Click Play from the top menu on Reality Editor.

- Click on the actor that you created on Reality Setup.

- Change the MyVariable to the 1 and 2, and 0. Check results.
- A debug message will be displayed on the Output Log Window in Reality Editor. Click on the Window > Developer Tools > Output Log


You can bind a blueprint function executed when the array variable has changed on Reality Setup. You can get a specified index that changed. The function name must follow this pattern OnChanged_ArrayName (underscore is required.)
- Create a new Actor class object. Click ADD NEW On Components tab. Add ZD ACTOR

- Create a new array variable.

- Create a new function and name it as OnChanged_ArrayOfFloats

- Click the function that you created. Add Integer parameter named as Index.

The function works only if it takes one parameter as a type of Integer.
- Connect the nodes as shown below.

- Put your actor to the level.
- Launch Reality Setup.
- Click Play from the top menu on Reality Editor.

- Click on the actor node that you created and add items onto the array and change of values.

- Check output log, and the Reality Editor executes the function with the specified index.

Last modified 6mo ago