IntentService 和 Activity 生命周期

Question

I followed this tutorial on how to reverse geocode in Android, but I can't understand how this IntentService will deal nicely with the Activity lifecycle. I am following this code sample .

As far as I understand, the Activity will hold an instance of the AddressResultReceiver , named mResultReceiver . When the IntentService get's back the reverse-geocoded address, it will call mReceiver.send(resultCode, bundle) from the mResultReceiver instace, which will then update the UI, inside the Activity .

My question is how will this play along with the Activity lifecycle. Lets assume the Activity started the IntentService and then, by some reason, it was destroyed (like, the user rotated the screen). Later, when the IntentService receives the address back from Google Maps, it will call the mResultReceiver it recevied from the original Activity , that is right now destroyed (or it could have been created again, but still, it will be a new instance anyway).

Since the mResultReceiver is created when the Activity is created, and it isn't saved on any Bundle for later retrieval, when the IntentService completes and calls the original mResultReceiver , what would happen?

• Will the mResultReceiver call be automagically forwarded to a new instance of the Activity , like nothing happend and all work as expected?

• Will mResultReceiver be Garbage Collected with the destroyed Activity , and the IntentService will throw an exception when it tries to use the destroyed class?

• Will mResultReceiver prevent the original Activity from being garbage collected, specially because the IntentService is still holding a reference to the mResultReceiver object. And when the IntentService calls mReceiver.send(resultCode, bundle) it will make no difference on the actual Activity on screen, or throw an exception for trying to update already destroyed UI Widgets?

• Is this google example flawed? What's the right way to do it then?

Answer 1

I believe the google example is flawed. The sample will result in a memory leak if activity is destroyed. A better approach would be using a local broadcast receiver or an Event Bus or RxJava/RxAndroid
Issue is already reported here