I have an app which was working just fine. I tried to evolve it slightly and so renamed it and made some minor adjustments and all appeared fine. However, the android version of the app started to misbehave without any obvious changes to the area in which the problem is occurring.
The main text input box (fine in iOS) doesn’t appear to want to accept any input in the Android version. On tap, the keyboard appears as you would expect, but it’s SLOW to appear. Then the curser appears but doesn’t flash. Then when typing in text, the characters do not appear at all.
So this is more or less an untouched iteration of an earlier app which worked fine in iOS and Android but now has a mystery bugginess to it.
On Jared’s advice, I had a timer block checking the text input block for focus (to make a button visible). Jared had suggested this to fire every 300 milliseconds, and (without fully understanding the need for 300 milliseconds) I had in fact reduced that to 50 milliseconds as an attempt to improve the response time. Then through series of interruptions and changes, I forgot to properly test that change, which in fact caused massive lag though strangely, only in Android and not iOS.
So if like me you are experiencing lagginess, if you have timers in your app, you might try experimenting with their interval values to try to cure your problem.