Android for Game Developers - Beginning Android Games - page 129

setContentView(textView);
log("created");
}

@Override
protected void onResume() {
super .onResume();
log("resumed");
}

@Override
protected void onPause() {
super .onPause();
log("paused");

if (isFinishing()) {
log("finishing");
}
}
}

Let's go through this code really quickly. The class derives from Activity —not a big surprise.
We define two members: a StringBuilder , which will hold all the messages we have produced
so far, and the TextView , which we use to display those messages directly in the Activity .
Next, we define a little private helper method that will log text to LogCat, append it to our
StringBuilder , and update the TextView text. For the LogCat output, we use the static
Log.d() method, which takes a tag as the first argument and the actual message as the
second argument.

In the onCreate() method, we call the superclass method first, as always. We create the
TextView and set it as the content view of our activity. It will fill the complete space of the
activity. Finally, we log the message created to LogCat and update the TextView text with our
previously defined helper method log() .
Next, we override the onResume() method of the activity. As with any activity methods that we
override, we first call the superclass method. All we do is call log() again with resumed as
the argument.

The overridden onPause() method looks much like the onResume() method. We log the message
as “paused� first. We also want to know whether the activity is going to be destroyed after the
onPause() method call, so we check the Activity.isFinishing() method. If it returns true , we
log the finishing event as well. Of course, we won't be able to see the updated TextView text
because the activity will be destroyed before the change is displayed on the screen. Thus, we
also output everything to LogCat, as discussed earlier.

Run the application, and play around with this test activity a little. Here's a sequence of actions
you could execute:

1. Start up the test activity from the starter activity.

2. Lock the screen.

3. Unlock the screen.