Android Question PhoneStateListener - Getting signal strength

[trueboss323]

Hello all, I need help with trying to receive the phone signal's strength with this library. I want to read the signal strength just once, instead of automatic. So I try using this code:

Dim PSL As PhoneStateListener
...
Sub button1_click
    Msgbox(PSL.CellLocation,"")
    Msgbox(PSL.GsmSignalStrength,"")
End Sub

The first Msgbox results in

[3812,242559177,-1]

but the second gives me an error

An error has occured in
sub:mainbutton1_click
(java line:234)
java.lang.
NullPointerException
Continue?

 

[Erel]

1. Use Log instead of Msgbox.
2. Can you post the full error message from the logs?

Have you tried to handle the onSignalStrengthsChanged event?

 

[trueboss323]

1. Use Log instead of Msgbox.
2. Can you post the full error message from the logs?

Have you tried to handle the onSignalStrengthsChanged event?

Here is the full log I get:

** Activity (main) Create, isFirst = true **
PhoneStateListener has been initialized.
** Activity (main) Resume **
[3032,7992,-1]
Error occurred on line: 50 (Main)
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.telephony.SignalStrength.getGsmSignalStrength()' on a null object reference
at com.rootsoft.phonestatelistener.PSL.getGsmSignalStrength(PSL.java:290)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at anywheresoftware.b4a.shell.Shell.runMethod(Shell.java:703)
at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:337)
at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:247)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:134)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:157)
at anywheresoftware.b4a.BA.raiseEvent(BA.java:153)
at anywheresoftware.b4a.objects.ViewWrapper$1.onClick(ViewWrapper.java:78)
at android.view.View.performClick(View.java:4856)
at android.view.View$PerformClick.run(View.java:19956)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5371)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:945)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:740)

I tried to use the onSignalChange event but it wouldn't get triggered. Plus i dont think that would be relevant for me since I only want to get the signal once and I assume that event is used for automatic.

 

[Erel]

The internal object is set in this event. You cannot call those methods before.

 

[trueboss323]

What would be the more appropriate way to call this event?

 

[Erel]

You shouldn't call it yourself. It should be raised by the library.

 

[KY Leng]

but the event seem not fire ...

Sub PSL_onSignalStrengthsChanged (signalStrength As String)
    'ToastMessageShow(signalStrength, False)
    'ToastMessageShow(PSL.CdmaDbm, False)
    Log("SignalStrength : " & signalStrength)
End Sub

 

[Martin Larsen]

Excuse me for opening this old thread, but I have the exact same problem as in #7 so I feel it is appropriate to use the same thread.

onSignalStrengthsChanged is apparently never fired. To trigger signal strength change I put the phone into my microwave oven (not turned on!) but the event is never fired.

I use the sample program included with the library.

 

[Erel]

It is never a good idea to post in an old thread. It is not clear where the question starts and where it ends.

 

[Martin Larsen]

Ok. I just thought that it would be nice for users coming to this thread via the search function to get an update on the problem since it was never solved for the OP.

I will start a new thread.

 

[Martin Larsen]

For other users coming to this thread with the same problem. The library apparently doesn't work anymore, but there is a working solution here without the library:
https://www.b4x.com/android/forum/threads/reading-title-bar-signal-strength.94324/