CODEWITHSUNDEEP
javaandroidandroid-activitybluetoothandroid-service
Matt199
Matt199

Reputation: 294

How to get access to values from every Activity using Service

I trying to make the app similar to Nissan Leaf Spy. This app receives data from bluetooth interface ELM 327. My goal is to collect data like:

And display them on real time chart using GraphView. For one parameter is one chart in Activity. So there are at least as many Activities as parameters I need to display. My guess is to use 

Android Services

to do work in background to co collect and save every data in different array via bluetooth. Of course when I change Activity to see another Activity the one that works will stop working and there will be no more real time. The question is: is there any kind of 'superclass' that is always working or do I need to save this data using SQL? Or should I just use intent.putExtraString(key,value) and getIntent().getStringExtra(key). I will be grateful for your help!

Upvotes: 0

Views: 72

Answers (1)

Aakash Verma
Aakash Verma

Reputation: 3994

About having different activities for different parameters, you need to have just one activity. You can have a graph and different ArrayLists with adapters for parameters and then use one of them to feed the graph according to the parameter selected say, from a Spinner.

To feed those ArrayLists is just as easy. You can have a Service running, for general data collection, with an AsyncTask inside it, which will keep the feed live for a selected parameter when the app is active and not in the background. The Service, by itself, can collect data in some sort of a buffer large enough to feed those graphs.

Remember, AsyncTasks are good for updating UI components without blocking the main thread.

EDIT: Look, if you have an activity (let's consider some other activity than main) where you're going to show the data or graph, you can have AsyncTask running as soon as you enter the activity(you can define a default parameter for a graph to be shown) or when you select from a drop down, giving you real-time data while you're on the activity.

The reason I am using AsyncTask for the live feed is that you can have different UI views and seamlessly integrate without any future problems and that it'd modularize Service into functionalities for serving Activity and would end when you close the app. The Service running in the background would primarily provide to a temp log file or be an InputStream source for AsyncTask when it runs after app launch or activity launch.

Upvotes: 1

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