Tutorials

We'll again build on the work in the previous threading tutorials but this time make the application more real world by splitting the threads off into their own classes. We do this to make them more manageable, and we'll add another background thread to make the planets spin around behind all the counters.

Following on from part 1, where we showed screens which updated only on finger press events, its time to get dynamic. We'll build on the first tutorial and make the numbers spin up all the time. This is a little more complex because it introduces a fundamental rule regarding threading on Android - one which was smartly side-stepped in part 1.

At their heart, computers are pretty simple beasts: they only do what you tell them to. Sometimes though, it looks like they are responding to events being fired from all directions at once. Well, thats because they've been told how to deal with those "random" events by interrupting the current flow. In Android a mechanism for this is called the Message Handling System. It's a way of writing software that can be interrupted at any time by predefined messages. These messages are generated by real world events like timers firing or the keyboard being opened, so here's an Android application to illustrate it.