Develop Reference

Running a bound service and a thread

I currently have a bound Service with my Main activity.
I was wondering if it was possible to have a Thread Running inside this bound Service that can pass integers to my Main Activity. This Service needs to auto update my Main Activity's Text View with any new Random number Integer without clicking a button.
Should i look into Handlers?? Or Message/ Bundles??
Any help would be appreciated ! Thank you !

You can define one Receiver your MainActivity and you can use send Broadcast to that receiver to update your UI.. That is a simple way to do it
In your service Just define one intent and put values into it like follwing
Intent i = new Intent();
i.setAction("RECEIVERACTION");
i.putExtra("data", "mydata");
sendBroadcast(i);
and in your activity
public static class Receiver extends BroadcastReceiver {
#Override
public void onReceive(Context context, Intent intent) {
String data = intent.getStringExtra("data");
textView.setText(data);
}
}
Hope it helps!!!

Please go through api guides. Specifically
https://developer.android.com/guide/components/bound-services.html
https://developer.android.com/guide/components/services.html
This should give you a pretty good idea to move forward and also code samples

Communication between Class and Main Activity Android

I am new in Android so I hope you can excuse my ignorance
I made an activity to control some bluetooth devices with my telephone, now that everything is working I would like to generate a new class from this activity, a class to take care of all bluetooth communication.
I have some questions:
First: In my activty I employed one broadcast receiver to listen to some actions of the Bluetooth Adapter like STATE_ON, BOND_BONDED... Using this actions I update my views, I call some methods and so on.
So, it is possible to keep listening to this broadcast receiver inside my class and then send the changes to my main activity to update the views and so on?
Second: I really need to send information from my bluetooth class to my main activity, information that I read from my devices, information from the broadcast receiver... so, which is the best way to pass information between a class and the main activity?
Well, thanks a lot for your help :)

The onReceive() method of your BroadcastReceiver is called from the main thread:
"This method is always called within the main thread of its process" (http://developer.android.com/reference/android/content/BroadcastReceiver.html#onReceive(android.content.Context, android.content.Intent)).
That means you can update your ui from the onReceive() method. All you need to do is use a local class like so:
BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// update the ui
}
};
Register this receiver programmatically (instead of defining it in the manifest) and you're good to go:
Context.registerReceiver(android.content.BroadcastReceiver, android.content.IntentFilter)

How get Activity form BroadcastReceiver in onReceive

I define BroadcastReceiver in an application manifest and the receiver receives events in onReceive as expected. However I do not create the receiver class so I can't pass any information about my activity which the receiver is supposed to control. Context parameter gives me only application context and no any activity reference. So what is right way to make communication between application activities and broadcast receiver?

The answer is a little twisted but I found it here as well
Inform Activity from a BroadcastReceiver ONLY if it is in the foreground
It seems working. Please close the question then.

You can communicate broadcast to activity from this:-
Intent intent=new Intent(context,YourActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);

stopService(intent_with_extras) - how do you read those extras from within the service to stop?

I have a Service that can be stopped in multiple ways. Whenever I call stopService(Intent), I pass an intent with some extras. How do you retrieve those extras?
Thanks.

You need to override onStartCommand() in your Service this is how you get a reference to the incoming intent from startService.
In this case you would have a special action in your intent to tell the service to stop itself. You add extras to this intend which can be read in the onStartCommand() method.
Sample Code
public class MyService extends Service {
#Override
public int onStartCommand(final Intent intent, final int flags, final int startId) {
final String yourExtra = intent.getStringExtra(YOUR_EXTRA_ID);
// now you can e.g. call the stopSelf() method but have the extra information
}
}
Explanation
Every time you call context.startService(Intent) onStartCommand() will be called. If the service is already running a new service isn't created but onStartCommand is still called. This is how you can get a new intent with extras to a running service.

I found that the extras are not passed with the intent when stopService is called. As a workaround, simply call startService(Intent) and stopService(Intent) right after one another.
Example code from Activity:
Intent j = new Intent(SocketToYa.this, AccelerometerDataSocket.class);
j.putExtra("com.christophergrabowski.sockettoya.DestroyService", true);
startService(j);
stopService(j);
In Service.onStartCommand,
intent.hasExtra("com.christophergrabowski.sockettoya.DestroyService")
will evaluate to true, and you will destroy your service the way intended by the API (i.e., by calling stopService, which will in turn call OnDestroy after onStartCommand is called).

My suggetion is that use static member in class that extends Activity for passing information to service & it in service as normal static member access in outside class
Please don't do this unless you have no other option. You should try to use the mechanisms built into the framework for passing data, and not use public static fields unless there is no other choice. Read the Service documentation for examples.

Are you able to use an Intent with a "shutdown" action with Context.startService()?
That is, send an Intent with a shutdown action and extras to Service.onStartCommand(), decide how to shutdown based on the extras, then use Service.stopSelf() to stop the service.
I agree this isn't a great solution, since it potentially starts the service in order to shut it down. I would still like to hear of the "correct" way (if one exists) of doing this with Context.stopService().

You can not write
getIntent()
method in a class extending Service. So I think using getExtra() won't work.
My suggetion is that use static member in class that extends Activity for passing information to service & it in service as normal static member access in outside class i.e.
Classname.yourobject
.
see this link for other option
http://developer.android.com/resources/faq/framework.html#3

Android from receiver to activity

I'm just getting into Android development, and I have a question about communicating between a receiver class and an activity class. I'm very new to JAVA and Android so I hope I don't sound too stupid. I'm developing an application where I intercept an SMS message and then based on various elements of that SMS I might delete it once it's been saved to the inbox. I have a receiver class that intercepts the txt message, and I am also able to delete messages from my inbox with code in the activity class using a button at the moment. The problem I have is communicating between the receiver class and the activity class where the code to delete a message resides. I tried putting that code directly into the receiver class but as I'm sure most of you already know the BroadcastReceiver class doesn't seem to support what I need to delete messages. I've been searching for an answer to this for a while, but haven't been able to find anything. Honestly I'm not sure I know enough about JAVA and Android to even recognize a solution if I saw it.

If you need to complete a job without an interface look into creating a Service, if you need user interface just start an Activity
You can use the Context parameter of the onReceive method of the receiver to start a new service/activity
You can use Extras to pass params between context. So you can put as extra the message id or entire message and pass it to your service/activity and deal it there.

You could implement the handling messages logic using an IntentService. When your receiver gets the new incomming message, start the IntentService passing an intent with the message data.
Receiver
onReceive(Context context, Intent intent) {
//Setup Intent
Intent i = new Intent(context, MyIntentService.class);
i.setAction(MyIntentService.HANDLE_MESSAGE);
//Pass data to intent
i.putExtra(MyIntentService.MESSAGE_DATA, data);
//Start Intent Service
context.startService(i);
}
MyIntentService
onHandleIntent(Intent i){
String action = i.getAction();
if(action != null && action.equals(MyIntentService.HANDLE_MESSAGE){
//Get data and implement message logic
}
}
Hope it helps.