The result of subscribe is not used
The moment the Activity will be destroyed, the list of Disposables gets cleared and we’re good.
io.reactivex.disposables.CompositeDisposable mDisposable;
mDisposable = new CompositeDisposable();
mDisposable.add(
Single.just(db)
.subscribeOn(Schedulers.io())
.subscribe(db -> db.get(1)));
mDisposable.dispose(); // dispose wherever is required
You can subscribe with DisposableSingleObserver:
Single.just(db)
.subscribeOn(Schedulers.io())
.subscribe(new DisposableSingleObserver<Object>() {
@Override
public void onSuccess(Object obj) {
// work with the resulting todos...
dispose();
}
@Override
public void onError(Throwable e) {
// handle the error case...
dispose();
}});
In case you need to directly dispose Single
object (e.g. before it emits) you can implement method onSubscribe(Disposable d)
to get and use the Disposable
reference.
You can also realize SingleObserver
interface by your own or use other child classes.
The IDE does not know what potential effects your subscription can have when it's not disposed, so it treats it as potentially unsafe. For example, your Single
may contain a network call, which could cause a memory leak if your Activity
is abandoned during its execution.
A convenient way to manage a large amount of Disposable
s is to use a CompositeDisposable; just create a new CompositeDisposable
instance variable in your enclosing class, then add all your Disposables to the CompositeDisposable (with RxKotlin you can just append addTo(compositeDisposable)
to all of your Disposables). Finally, when you're done with your instance, call compositeDisposable.dispose()
.
This will get rid of the lint warnings, and ensure your Disposables
are managed properly.
In this case, the code would look like:
CompositeDisposable compositeDisposable = new CompositeDisposable();
Disposable disposable = Single.just(db)
.subscribeOn(Schedulers.io())
.subscribe(db -> db.get(1)));
compositeDisposable.add(disposable); //IDE is satisfied that the Disposable is being managed.
disposable.addTo(compositeDisposable); //Alternatively, use this RxKotlin extension function.
compositeDisposable.dispose(); //Placed wherever we'd like to dispose our Disposables (i.e. in onDestroy()).