final NodeModel<String> nodeA = new NodeModel<>("A");
        final NodeModel<String> nodeB = new NodeModel<>("B");
        ...
        final NodeModel<String> nodeZ = new NodeModel<>("Z");


        final TreeModel<String> tree = new TreeModel<>(nodeA);
        tree.addNode(nodeA, nodeB, nodeC, nodeD);
        ...

        int dx = DensityUtils.dp2px(this, 20);
        int dy = DensityUtils.dp2px(this, 20);
        int mHeight = DensityUtils.dp2px(this, 720);
      
        testTreeView.setTreeLayoutManager(new RightTreeLayoutManager(dx, dy, mHeight));
        testTreeView.setTreeModel(tree);