Android Question Widget service lifecycle...

tunderin · Sep 23, 2013

Hi everybody,

I spent some time searching outside of this forum - Stack Overflow & such - but came up empty handed...

The B4A documentation says that the widget service is just a regular service, but when I deliberately stop the service, Android immediately starts it again. That would make sense because it handles events from widget views, etc

That behavior would also suggest to me that a widget service is more like a sticky service & that it runs almost 100% of the time. This would seem to make my widget service a better home for my phone call listener (using PhoneEvents) than building it in a service of its own.

Are my assumptions correct?

Erel · Sep 24, 2013

I actually think your best option is to use a static filter (with the widgets service): Intent Filters - Intercepting SMS messages in the background

tunderin · Sep 24, 2013

Thanks Erel... I see the advantages

My end objective is to get the telephone number of the incoming call so that I can pop an information panel (with data from the DB) over the incoming call screen.

I should be able get there using "Android.Telephony.LISTEN_CALL_STATE" and manifest permission "android.permission.READ_PHONE_STATE" - correct?

Erel · Sep 25, 2013

tunderin · Sep 25, 2013

Thanks Erel,

This is my test app's manifest in which I set up my intent filter:

B4X:

'This code will be applied to the manifest file during compilation.
'You do not need to modify it in most cases.
'See this link for for more information: http://www.b4x.com/forum/showthread.php?p=78136

AddManifestText(
<uses-sdk android:minSdkVersion="8" />
<supports-screens android:largeScreens="true"
    android:normalScreens="true"
    android:smallScreens="true"
    android:anyDensity="true"/>)
SetApplicationAttribute(android:icon, "@drawable/icon")
SetApplicationAttribute(android:label, "$LABEL$")
'End of default text.
AddPermission(android.permission.READ_PHONE_STATE)
AddReceiverText(Listener,
<intent-filter>
    <action android:name="android.telephony.PhoneStateListener.LISTEN_CALL_STATE" />
</intent-filter>)

My service is named "Listener" & it starts with:

B4X:

Sub Service_Start(startingIntent As Intent)
    Log("Listener Service started.")
    If startingIntent.Action = "android.telephony.PhoneStateListener.LISTEN_CALL_STATE" Then
        Dim callState As List
        Dim r As Reflector
        callState = r.RunStaticMethod("android.telephony.PhoneStateListener","onCallStateChanged",Null,Null)
        Log("CallState="&callState)

    End If
   
End Sub

When I place a call to my dev phone, the service is not started.

Is there anything obviously wrong in the above?

Thanks...

NJDude · Sep 25, 2013

Check your capitalization.

Also, take a look at THIS sample, you could modify it to trigger when a phone call is received (RINGING or OFF_HOOK)

tunderin · Sep 25, 2013

Thanks NJDude,

I corrected the capitalization but it still doesn't work.

I originally used PhoneEvents (as in your sample) to implement a listener & looked to give it a home in my widget service (hence this thread) which I would then need to run in foreground. Erel suggested a static filter which suited my purposes better.

From his link:

Difference between static and dynamic receivers
The main difference between the two types of receivers is that dynamic receivers listen to intents as long as the process is running.

Static receivers always work. If the process is not running then it will be created.

Normal processes eventually get killed. This means that you cannot rely on dynamic receivers to intercept intents when your application is in the background. A possible workaround is to call Service.StartForeground in the service. This will prevent the process from being killed. However this will also add an ongoing notification icon (see the Services tutorial for more information).

It seems to me to be a more elegant solution for a listener - now I just have to make it work...

NJDude · Sep 25, 2013

I'm not sure, but I think the action should be:

B4X:

 android.intent.action.PHONE_STATE

instead of

B4X:

android.telephony.PhoneStateListener.LISTEN_CALL_STATE

tunderin · Sep 25, 2013

Are you talking about substituting in the manifest or the service_start sub?

NJDude · Sep 25, 2013

Both.

tunderin · Sep 26, 2013

Thanks NJDude, that worked! I found the incoming telephone number that I needed in the intent extras.

I had poked around the TelephonyManager class during the course of this effort but went PhoneStateListener instead. Was there something fundamental that I overlooked that made your suggestion the more appropriate way to go?

NJDude · Sep 26, 2013

Well, you are listening for that event which will start the service, so, unless I'm not seeing something (or understanding) using the filter + the PhoneEvents looked good to me, so, what's the final code you ended up with?

tunderin · Sep 26, 2013

This is what I ended up with - I still can't explain why PhoneStateListener class didn't work...

Be good NJDude

B4X:

'This code will be applied to the manifest file during compilation.
'You do not need to modify it in most cases.
'See this link for for more information: http://www.b4x.com/forum/showthread.php?p=78136

AddManifestText(
<uses-sdk android:minSdkVersion="8" />
<supports-screens android:largeScreens="true"
    android:normalScreens="true"
    android:smallScreens="true"
    android:anyDensity="true"/>)
SetApplicationAttribute(android:icon, "@drawable/icon")
SetApplicationAttribute(android:label, "$LABEL$")
'End of default text.
AddPermission(android.permission.READ_PHONE_STATE)
AddReceiverText(Listener,
<intent-filter>
    <action android:name="android.intent.action.PHONE_STATE" />
</intent-filter>)

B4X:

Sub Service_Start(startingIntent As Intent)

    Log("Listener Service started.")
    Log("startingIntent="&startingIntent)

    If startingIntent.Action = "android.intent.action.PHONE_STATE" Then
        Log(startingIntent.ExtrasToString)

    End If
   
End Sub

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