CODEWITHSUNDEEP
androidandroid-intent
chromicant
chromicant

Reputation: 103

Passing data from a Service

I have an Android service which collects data from some external hardware. I am making that data available to my Activities using a callback structure shown here.

The data I'm making available is an ArrayList<MyClass>. While reading the Android API docs, it seems that a suggested way is to use broadcast events and Parcelable. I've also seen callbacks used in Android apps, so the question is what's the advantage of refactoring my code to use broadcasts?

Now, in the future, I am looking to allow external apps to access this service (Tasker, for example), so I'm guessing that the callback method I use will be for use in the local app only. So the question is how to do a callback from a Service to an Activity using an AIDL description.

Upvotes: 1

Views: 119

Answers (1)

JT.
JT.

Reputation: 633

The way to allow a service to callback into an Activity is to have the service aidl interface define a registration function that takes another aidl interface as a parameter.

ServiceAidlInterface.aidl:

package com.test;

import com.test.CallbackAidlInterface;

interface ServiceAidlInterface {
    void registerCallback(in CallbackAidlInterface callback);
}

CallbackAidlInterface.aidl:

package com.test;

interface CallbackAidlInterface {
    void doCallback();
}

In your activity you need to define the following:

ServiceAidlInterface mService = null;

private CallbackAidlInterface mCallback = new CallbackAidlInterface.Stub() {
    @Override
    public void doCallback() throws RemoteException {
    }
};

So when the activity binds your onServiceConnected() gets called you can do the following:

   mService = ServiceAidlInterface.Stub.asInterface(serviceBinder);
   service.registerCallback(mCallback)

Upvotes: 1

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