I have an app on Android that reacts to incoming calls.
Now, since the OS shuts my app down whenever it want,
I need a way to to listen to the incoming calls and launch the app when it happens.
Will a BroadcastReceiver help? (just like launching on device restart)
Any idea?
thanks!
I think you have answered your own question. This is just the sort of thing a broadcast receiver is meant for. If the receiver is registered in your manifest then the application does not have to be running.
It will be automatically started when a matching intent is broadcast. Typically the response will be to update content or activities, make notifications with the Notification manager or launch/manipulate services.
Note that there is a 5 second execution limit in the BroadcastReceiver onReceive handler to ensure you do not try to do any 'heavy lifting' in it. Exceed this and a force close dialog will be displayed.
Yes a BroadcastReceiver would to the job as it will fire even you app is not running.
Related
I am developing an app and this app needs to give a clear indication to the user when some event happens.
Only thing I could do until now is giving a notification in the notification area. But, I need to give a more visible notification, similar to the behavior when phone is ringing in an incoming call.
As I can understand, the reason why android is only allowing apps to give a notification is to prevent apps from disturbing the user. But, this app I am developing plays a vital role in the job of the user, so I don't think it is inappropriate to give a such strong notification.
I know it should be doable since apps like Viber can start an activity similar to a incoming phone call, even when the device is sleeping.
Does anyone know how to get this done?
Register a broadcast receiver, and add a custom action to it say CustomAction.Instead of showing notification, throw a broadcast and add CustomAction via intent filter.
Now in the onReceive method of broadcast listener, check
if(intent.getAction.equals("CustomAction"))Intent i = new Intent(context, YourActivity);
context.startActivity(i);
Sorry for not a formatted answer, I'm driving, will update it later for more clarification.
Update
Register broadcast receiver in a sticky service. So that service can be started automatically if killed and register broadcast register again.
Don't forget to unregister broadcast receiver in onDestroy() method of service and also in YourActivity when you purpose is resolved.
Just adding a sticky service (which does nothing) fixed the issue. Adding the service prevented the process getting killed when user exits the app and removes it from recent app list.
Because of the service, the app process is running even when a no UI is visible. In this state, if an activity is shown from the GCM service, it gets shown.
You can trigger a broascast as Vinay mentioned. If it still does not work, try using wake-locks. These wake-locks help in waking the device when it is in sleep mode. It will act like force wake and after calling wake-locks, you can perform your actions.
Hope it helped..
Thanks.
This might be a foolish question for you, Please consider that im not an expert in Android programming.
I had implemented a PhonestateListener with an inline code in my Service.But after following the broadcast tutorial from here.I saw the same phoneStatelistener is explained with the help of a BroadcastReceiver.Can anyone pls explain me the benefits?Thanks.
A Broadcast receiver wakes your application up, the inline code works only when your application is running.
For example if you want your application to be notified of an incoming call, even if your app is not running, you use a broadcast receiver.
If your application is playing audio, and you want to stop the music on an incoming call, you use the inline code.
A broadcast receiver also called as receiver is an Android component which allows you to register for system or application events. All registered receivers for an event are notified by the Android run time once this event happens. Broadcast receiver is also called the gateway between your application and outside world.
example of broadcast receiver is when new sms arrives, broadcast receiver sends notification to messaging app and small icon pops up in notification bar.
rules of broadcast receiver:
it has maximum limit of 10secs,
do not do any asynchronous operations which may take more time,
do not do heavy database operations or networking operations in broadcast receiver.
I currently have 2 apps in the market, let's call them app A and app B.
When a certain function is executed in app, I need something to trigger an event in app a, even if app a isn't currently running. I assume app B would send a broadcast message to app a and app a would need a broadcast receiver but I am not sure how this can be done, if it can be done.
There are basically two ways afaik:
Broadcast Receiver and using the sendBroadcast method on the sender side
or by using Intents:
you can use startActivity(Intent) even with another app, but this will bring the app to foreground rather than doing a job in background.
Use intents if the calling app should dissappear and the called app should be in foreground and use broadcasts if you just want a background task performed by another app
Can be done, even if the app isn't running, with BroadcastReceiver, just like you said.
I want to know the difference between services and broadcast receivers, can anyone point out an example that can be observed on android mobile devices.
Thanks
Service: If you want to do something in background , this will be running always in background even if the application closed. You can create this in separate process and also you can give your service to other app if you want. Downloading any content or Music is good example
Broadcast Reciever: Usually system will send some info which can be recieved by your app if you would wish to ,by registering. And you can do something what you want when that thing happens by using onReceive method.
Example is the system will send BroadcastReceiver when new sms arrives or Booting done
Here is good article : Service and BroadcastReceiver
Service is used when you want to do something in background, any long running process can be done using Service in Background. For example, you want to play music when your application gets close. In that case service will be running in background with music.
Example of Service
BroadcastReceiver is used when you want to fire some stuff or code during some event. For example, event can be on Boot of Device. If you want to perform something when device Boots, date and time changed etc...
Example of BroadcastReceiver
I think of it possibly a different way. A Service receives intents that were sent specifically to your application, just like an Activity. A Broadcast Receiver receives intents that were broadcast system-wide to all apps installed on the device.
(The reason I say a Service is a bit like an Activity is that: You wouldn't broadcast a message saying "start Activity MyActivity" across all apps installed on the device. It is only for your specific app.)
Of course, as others mentioned, a Service can continue running in the background, whereas a Broadcast Receiver should finish quickly (e.g. if it is running for more than 5 seconds it may be killed by the OS). The Broadcast Receiver can still run in the background (when app is closed) under certain circumstances. For this, it's worth mentioning that there are actually two types of Broadcast Receivers - Manifest-declared, and Context-registered. They have different lifespans and restrictions - the former can receive broadcasts in the background with certain restrictions, while the latter cannot receive broadcasts in the background (app must be running and active) but has no restrictions on the types of intents that can be received.
Both services and broadcast receivers must be specifically invoked (via an intent), but for services this is usually a specific call (e.g. when your app is started or when the user clicks some button) whereas for broadcast receivers they don't need to be explicitly started as they will start anyway when a relevant broadcast is made.
Here's how I would think of it:
Type
Displays UI?
Can continue running for a long time when app is closed?
Can receive intents when app is closed?
Intents must specifically target your app?
Restricted list of intents that can be specified?
Activity
Yes
No
Yes
Yes
No
Service
No
Yes
Yes
Yes
No
Manifest-declared Broadcast Receiver
No
No
Yes
No
Yes1
Context-registered Broadcast Receiver
No
No
No
No
No
1: Only if you target Android 8.0 or above. The restrictions are not applied if the intent specifically targets your app. The restricted list of intents can be found here.
If a declare a BroadcastReceiver in AndroidManifest.xml, the reciever works, as it should, even on device boot when my application hasn't started yet, but if I force my app to stop from Settings the receiver seems to break down too.
Can it be that "Force stop" in Android 2.2 also makes some cleanup after the application (including BroadcastReceivers or maybe alarms set by the app in AlarmManager which should broadcast the intents I receive)?
By the way, how can I see in Eclipse all broadcasts being sent in the device?
Psycho,
Force Stop should not be used to attempt to test your app from a "non-running" state. I would say the behavior is "undefined" at best. It is not uncommon that after using Force Stop on an app, that you must manually restart it to get ANY of its usability back (including BroadcastReceiver). If your app is able to receive BroadcastReceiverevents including the BOOT_COMPLETE Broadcast than you shouldn't really need to test it further.
I believe the intended purpose of Force Stop was to completely stop an annoying app's functionality. If an app is running in the background often because its receiving a lot of broadcasts and restarting, wouldn't you think Force Stop should prevent that behavior until the app is manually restarted by the user?
Also, I don't believe there is a way to view Broadcast events from Eclipse.
In eclipse there is no way to see the "broadcast is sent"
Also If you have registered the Broadcast in manifest for which you want to receive the event then system will call onReceived method