How do I delete individual renderables from the scene using a button using arcore and sceneform?

Question

I'm trying to make a button that will delete a 3d model from the scene after it is selected.

I know that the way to delete 3d objects is by using anchor.detach(). And I can select individual models using node.select(). However, I am not sure how to access the anchor after selecting the node.

FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                deleteObject(//I'm not sure how to get the anchor from the selected node//);
            }
        });

private void deleteObject(Anchor anchor){
        anchor.detach();
    }

Answer 1

If you want to delete a particular Renderable and you already know the Anchronode, which is what I believe your case is from the question, then the code below will remove the Renderable and Anchornode:

private void removeAnchorNode(AnchorNode nodeToremove) {
        //Remove an anchor node
        if (nodeToremove != null) {
            arFragment.getArSceneView().getScene().removeChild(nodeToremove);
            nodeToremove.getAnchor().detach();
            nodeToremove.setParent(null);
            nodeToremove = null;
            Toast.makeText(LineViewMainActivity.this, "Test Delete - anchorNode removed", Toast.LENGTH_SHORT).show();
        } else {
            Toast.makeText(LineViewMainActivity.this, "Test Delete - markAnchorNode was null", Toast.LENGTH_SHORT).show();
        }
    }

The toast are just to help testing so can be removed or left as you choose.

Update - Kotlin version (tested April 2020):

    private fun removeAnchorNode(nodeToRemove: AnchorNode) {
        //Remove an Anchor node
        arFragment.getArSceneView().getScene().removeChild(nodeToRemove);
        nodeToRemove.getAnchor()?.detach();
        nodeToRemove.setParent(null);
        nodeToRemove.renderable = null
    }