I've used Java's debugger to do "live" UI editing on Android for around a decade now. Far in advance of first-party support / live-updating things being popula

I've used Java's debugger to do "live" UI editing on Android for around a decade now. Far in advance of first-party support / live-updating things being popular. Just set a timer to call back to the main thread every 100ms or so. When you get to the point in an application where you want to make changes, put a breakpoint in that callback. When it pauses, pop open the expression editor and start changing the UI. Make some views, adjust some values, etc. When you want to see the results, hit "continue"; it'll release the main thread for about 100ms (more than enough time to re-layout and render), then you'll be back in the debugger for another round of changes. You can hack up a full, polished-looking and often working UI in a couple minutes, and then just print the whole tree to get a snapshot your work. That same strategy works in basically any language with GDB support, in many, many UI frameworks, if the connection is sophisticated enough to call functions.