Connot get correct selection in childNode

Now I have a Node which have a textNode as childNode. I want to select text so I set nodeview’s setSelection but selection is wrong. The TextSelection is whole childNode but I want to select a part of it. How should I do.

Text selections can select parts of text nodes. But selecting is not done through node views — you have to dispatch an editor transaction that sets the selection.

thank you, and Now I get the Selection, but I want to add Decoration in childNode, How should I do. * It doesn’t seem to work use Decoration.inline