https://blog.substitute.tech/en/tags/ui/ Recent content in Ui on Haoxiqiang's Blog Hugo en Wed, 16 Dec 2015 18:15:33 +0000 https://blog.substitute.tech/en/posts/treeview%E6%A0%91%E5%BD%A2%E8%8F%9C%E5%8D%95/ Wed, 16 Dec 2015 18:15:33 +0000 https://blog.substitute.tech/en/posts/treeview%E6%A0%91%E5%BD%A2%E8%8F%9C%E5%8D%95/ <p>I had long wanted to write a tree view demo. Previously, I used <code>TreeViewList</code> (a <code>ListView</code> wrapper) or <code>ExpandableListView</code> for multi-level menus. Eventually I realized there is no need for custom views &ndash; just use <code>RecyclerView</code> and manage the data flattening yourself.</p> <p>The core idea: recursively flatten a nested data structure into a linear list, then use <code>notifyItemRangeInserted</code> / <code>notifyItemRangeRemoved</code> to handle expand and collapse.</p>