Is there way to keep a text view and a slider in sync to a CGRect's float value with bindings?

Question

I've been trying to get a text view and a slider to be updated to the correct value when either one has been modified.

Using bindings, I've successfully linked each control to a CALayer's "x" value position (layer.position.x). The layer does move when any of the controls are changed. However, when modifying one of the controls, I cannot get the other control to update itself to reflect the newly changed value.

I tried to implement my own setter and getter methods that align with the KVC standards, but the getter method I have is not getting called. I'm thinking because it's a primitive value that I'm modifying directly, the KVO for that value is not there. Is there a way to do this with bindings?

Thank You,

Charles

Answer 1

Text views, text fields, and CALayers are all in the view layer of the MVC pattern. You'll have much better results by binding all of those views to a property of your controller.

If I had to guess a specific reason why binding to the layer doesn't work, I'd point to Core Animation's extensions to KVC, and guess that the automatic KVO magic doesn't work with it.

I don't think CALayers expose any bindings, so you're just going to have to make the controller's setter explicitly propagate the change to the CALayer.