Develop Reference

How to send data from IntentService to a paused Activity?

The snippets below works when the activity is at the foreground. However, MainActivity will fail to receive the broadcast when MainActivity is at the background.
How do I make sure that MainActivity will always receive the broadcast? Is there any other way to send data from IntentService to a paused activity?
In my IntentService, I'm sending data back to MainActivity like this
Intent intent = new Intent();
intent.setAction(MY_SERVICE_RESULT);
intent.putExtra(MY_SERVICE_VALUE, "hello from service");
LocalBroadcastManager.getInstance(context).sendBroadcast(intent);
In my activity, I'm using BroadcastReceiver like this
public class MainActivity extends AppCompatActivity{
BroadcastReceiver receiver;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
receiver = new BroadcastReceiver(){
#Override
public void onReceive(Context context, Intent intent) {
String value = intent.getStringExtra(MY_SERVICE_VALUE);
}
};
#Override
protected void onResume() {
super.onResume();
IntentFilter intentFilter = new IntentFilter();
intentFilter.addAction(MY_SERVICE_RESULT);
LocalBroadcastManager.getInstance(this).registerReceiver(receiver, intentFilter);
}
#Override
protected void onPause() {
super.onPause();
LocalBroadcastManager.getInstance(this).unregisterReceiver(receiver);
}
}
}

How do I make sure that MainActivity will always receive the broadcast?
You can't.
However you could work around it by storing the data that the IntentService wants to send to the MainActivity somewhere temporarily (e.g. SharedPreferences), and have MainActivity check that storage in onResume.
Possible scenario
IntentService does its thing. Checks if MainActivity is active*. If it is -> send broadcast. If it's not -> store somewhere and let MainActivity check that storage in onResume.
*you can use Application's lifecyclecallbacks to monitor activity's states to see if an activity is running and if so which one.

Broadcast receiver not working in some cases

So i have this receiver in my Fragment.class
private BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
if (intent.getAction().equals(WeekplanHepler.ACTION_SERVICE_BINDED) && getUpdateService() != null) {
getCounts();
}
if (intent.getAction().equals(Helper.UpdateCounts)) {
HashMap<String, Integer> counts = (HashMap<String, Integer>) intent.getSerializableExtra(Helper.PARAM_LIST_COUNTS);
// Updating counts
}
}
};
For registering/uregistering this receiver i'm using this code:
#Override
public void onStart() {
super.onStart();
getCounts(true);
getActivity().registerReceiver(receiver, getIntentFilter());
}
#Override
public void onStop() {
super.onStop();
getActivity().unregisterReceiver(receiver);
}
getCounts() is a RetrofitRequest puted in UpdateService, which is getUpdateService() here
So, when retrofit request has been finished, it returns counts through Intent and then, as you see, i'm updating them. But if i go to next Activity and then returns, request will work fine, and it will send intent, but receiver wont get it. I think this can be caused by method service is binded in first place. So i have BaseFragment, which binds service for all Fragments needed
public abstract class BaseFragment<T> extends CustomListFragment<T> {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getActivity().getApplicationContext().bindService(new Intent(getActivity().getApplicationContext(),
WeekplanUpdateService.class), connection, Context.BIND_AUTO_CREATE);
}
}
When i go to next activity, it fragment will bind service, and my previous fragment will call request again, and will have counts. Maybe receiver has some limitations for how much he can get same intents, but i don't think so. Please help
Oh, i forgot to mention how i'm sending intent
sendBroadcast(new Intent(Helper.UpdateCounts).putExtra(Helper.PARAM_LIST_COUNTS, counts));

So, when i've started to use
sendStickyBroadcast(new Intent(Helper.UpdateCounts)
.putExtra(Helper.PARAM_LIST_COUNTS, counts));
instead of
sendBroadcast(new Intent(Helper.UpdateCounts)
.putExtra(Helper.PARAM_LIST_COUNTS, counts));
it worked.

send action from receiver to activity?

I am using broadcast receiver in my app to detect incomming call and it works fine. But problem is I can not send action to activity. I mean.. I want do something in activity not in receiver. I read many tutorial but they all are performing action in receiver. Any idea ?

You can declare a BroadcastReceiver as inner class of the Activity. In this case you can directly call activity's methods:
public class MyActivity extends Activity {
private final BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
activityMethod();
}
};
private final IntentFilter filter = new IntentFilter("android.intent.action.PHONE_STATE");
#Override
protected void onStart() {
super.onResume();
registerReceiver(receiver, filter);
}
#Override
protected void onStop() {
super.onPause();
unregisterReceiver(receiver);
}
private void activityMethod() {
}
}

You can start the Activity using an Intent and put a command code in the Intent extra fields. In your Activity you can then decide the behaviour based on the command code or resort to a default behaviour if none is present.

You can start an activity from your receiver via the normal means:
#Override
public void onReceive(Context context, Intent intent) {
Intent i = new Intent(context, YourActivity.class);
startActivity(i);
}
Note though that the user is going to expect that the phone application starts up since they are receiving a phone call. It is very likely a bad idea to hijack the phone call by dumping your own activity on top of the stock dialer app.

Finishing an Activity from a Broadcast Receiver

I have an Activity that I display as modeless when the phone rings (over the phone app). I would like to finish the Activity when either of the following events occur. The first is if I touch anywhere outside the Activity (this is not a problem), the second is if the ringing stops. I am listening for IDLE_STATE in the broadcast receiver but I am not sure on how to call the finish on the activity when I see it. The receiver is not registered by the activity but by the Manifest.xml

write the code in your receiving broadcast now this will send another broad cast with the intent named "com.hello.action"
Intent local = new Intent();
local.setAction("com.hello.action");
sendBroadcast(local);
Now catch this intent in the activity with you want to finish it and then call the super.finish() on the onReceive method of your receiver
like this
public class fileNamefilter extends Activity {
ArrayAdapter<String> adapter;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
IntentFilter filter = new IntentFilter();
filter.addAction("com.hello.action");
registerReceiver(receiver, filter);
}
BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
finish();
}
};
public void finish() {
super.finish();
};
}
this will finish the activity

What if you register another broadcast receiver from the activity. Then, when you want to kill it, send a broadcast message from the broadcast receiver that you mentioned.

I actually ended up adding a PhoneStateListener in the Activity to listen for IDLE_STATE.

After a long R&D over internet i have solved my problem. The below code is helpful if you start an activity from broadcast receiver and
clear all activity stack instance.
#Override
public void onBackPressed() {
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
} else {
moveTaskToBack(true);
}
}

I used this code to solve my problem. finish is the method of Activity, so call Activity and context like:
if (state.equals(TelephonyManager.EXTRA_STATE_IDLE)) {
Log.e(TAG, "Inside EXTRA_STATE_IDLE");
((Activity) arg0).finish();
}

Android Best Practice on Updating the UI from BroadcastReceiver to a certain activity

When i have a broadcastReceiver say android.intent.action.MEDIA_BUTTON and i want to update the current activity's UI without creating a new activity, is there any good practice on this one?
What i know (might not be correct)
1) I can put the BroadcastReceiver in the same class as the activity and call the updateUI function after certain activity
2) Create a ContentObserver?
3) Communicate to a service created by the activity, use aidl. (I dont know how to get the current service if its registered from an activity)
4) Create a custom filter on the broadcastReceiver located on the same class as the activity, and use context.sendBroadcast(msg of custom filter) and in the custom filter call updateUI (same as one but more generic?)
The final flow is it would come from a BroadcastReceiver and ends up updating the UI without renewing the activity (unless the activity is dead?)
Kindly provide links/source code on your how you tackle this kind of problem. Thanks a lot in advance :)

The easiest way to provide this functionality is to put the broadcast receiver in you Activity and bind / unbind it using registerReceiver and unregisterreceiver:
public class MyActivity extends Activity {
private BroadcastReceiver mBroadcastReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
MyActivity.this.receivedBroadcast(intent);
}
};
#Override
public void onResume() {
super.onResume();
IntentFilter iff = new IntentFilter();
iff.addAction("android.intent.action.MEDIA_BUTTON");
// Put whatever message you want to receive as the action
this.registerReceiver(this.mBroadcastReceiver,iff);
}
#Override
public void onPause() {
super.onPause();
this.unregisterReceiver(this.mBroadcastReceiver);
}
private void receivedBroadcast(Intent i) {
// Put your receive handling code here
}
}
Depending on the intent you wish to receive, you may need to add the appropriate permissions to your AndroidManifest.xml file.

What I recently had to do to change a Button's text after receiving data from a LocalBroadcastManager is to store the value in a private field and then do the UI stuff in my onResume() method.
public class myClass extends Activity {
private String myString;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// register to receive data
LocalBroadcastManager.getInstance(getActivity()).registerReceiver(receiver, new IntentFilter("myAction"));
}
private BroadcastReceiver receiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
// get the extra data included in the intent
myString = intent.getStringExtra("myString");
}
};
#Override
public void onResume() {
super.onResume();
System.out.println("onResume");
// do something to the UI
myButton.setText(myString != null ? myString : "Default");
}
}