Question

I have a singleton which stores some prudent information about the user of my application. At the moment, it stores the user’s login and the user’s location.

1)
The location is found via a Service. At the moment, the Service references my singleton directly to stuff the longitude and latitude into it. I would like to use a BroadcastReceiver to send a broadcast that the singleton hears and uses to update the values, instead.

However, to register the BroadcastReceiver, I need a Context in my singleton. What is the slickest way to achieve what I’m wanting. Is BroadcastReceiver possibly not the appropriate object?

2)
Also, what problems am I looking at with using a singleton? I assume that Android will possibly reclaim this memory at any given time (which would obviously be bad); so how can I prevent that? Would passing in the application’s Context and storing it in a member variable thwart this?

The Android documentation states: “But, the life cycle of a static is not well under your control; so to abide by the life-cycle model, the application class should initiate and tear down these static objects in the onCreate() and onTerminate() methods of the Application Class,” but I’m not entirely sure how to accomplish this.

Answer 1

However, to register the BroadcastReceiver, I need a Context in my singleton. What is the
slickest way to achieve what I’m wanting. Is BroadcastReceiver possibly not the appropriate > object?

The “slickest way” is to not do what you are doing. Please only register a BroadcastReceiver from an Activity, Service, or maybe an Application. You must unregister this BroadcastReceiver when the Activity, Service, or Application is destroyed.

I assume that Android will possibly reclaim this memory at any given time (which would
obviously be bad); so how can I prevent that?

You don’t. Android reserves the right to terminate your process at any time (e.g., to reclaim memory). Task killers on Android 2.1 and previous will terminate your process at any time. Once all components of your application are destroyed, Android may recycle your process at any time, clearing out your heap at the same time. And so on.

Only put things in memory that you don’t mind losing.

It is best to think of your “application” as a basket of loosely-coupled components, not as a monolithic entity.

Would passing in the application’s Context and storing it in a member variable thwart
this?

No.

The Android documentation states: “But, the life cycle of a static is not well under your
control; so to abide by the life-cycle model, the application class should initiate and
tear down these static objects in the onCreate() and onTerminate() methods of the
Application Class,” but I’m not entirely sure how to accomplish this.

Create a subclass of Application and indicate in the manifest that Android should use it, via the android:name attribute on the <application> element.