SmartThings Has added support for the 4 button Ecosmart handheld remote. This is a zigbee battery powered device available in both the US and Canada at Home Depot.
Very low price, usually under $10 for the remote and an included smart bulb. If it’s out of stock in the set with one bulb, check the set with two bulbs, it’s typically only two dollars more.
you don’t need any custom code for it. And you can control any device that works with the hub, not just zigbee devices. 
Please ask any further questions about it in the following device specific discussion thread: