Can a static arraylist of data objects cause memory leaks while the homescreen widget is running

Question

In the following code i have a Class that contains a bunch of variables. I create a couple of instances of that class and save them to an arraylist. The arraylist is part of the same class, but marked static. The same app has a homescreen app widget. I worry that the static arraylist will stay in memory forever until the user deletes the app widget. Is this true? Is the static arraylist a good idea or what could be an alternative?

public class Data {
    public static ArrayList<Data> listData = new ArrayList<Data>();
    String string;
    int integer;
    Data(String string, int integer){
        this.string = string;
        this.integer = integer;
    }
}

public class DataChanger {
    DataChanger(){
        Data.listData.add(new Data("string", 1));
    }
}

score 2 · Accepted Answer · edited Jun 20 '20 at 09:12

static arraylist will stay in memory forever until the user deletes the app widget

That is unlikely to occur, since the AppWidgetProvider is a convenience BroadcastReceiver class for Android widgets. If nothing else of your application is running, your process may be terminated between onUpdate() calls.

The official docs for BroadcastReceiver make it very clear that

A BroadcastReceiver object is only valid for the duration of the call to onReceive(Context, Intent). Once your code returns from this function, the system considers the object to be finished and no longer active.

This has important repercussions to what you can do in an onReceive(Context, Intent) implementation: anything that requires asynchronous operation is not available, because you will need to return from the function to handle the asynchronous operation, but at that point the BroadcastReceiver is no longer active and thus the system is free to kill its process before the asynchronous operation completes.

In particular, you may not show a dialog or bind to a service from within a BroadcastReceiver. For the former, you should instead use the NotificationManager API. For the latter, you can use Context.startService() to send a command to the service.

References - Reference 1, Reference 2, Reference 3

Can a static arraylist of data objects cause memory leaks while the homescreen widget is running

1 Answers1