Android Question MLScan listSavedNetworks problem <SOLVED>

Discussion in 'Android Questions' started by SimonatMSL, Dec 11, 2017.

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  1. SimonatMSL

    SimonatMSL Member Licensed User

    Hi

    I am trying to run this code snippet to get a list of saved wifis:

    Sub Activity_Resume
    Log("Activity_Resume called")
    Dim myAPlist As List
    myAPlist.Initialize
    myAPlist = myScan.listSavedNetworks
    Log(myAPlist)
    End Sub

    but I am getting the error

    Process_Globals called
    *** Service (starter) Create ***
    ** Service (starter) Start **
    Globals called
    ** Activity (main) Create, isFirst = true **
    Activity_Create completed
    ** Activity (main) Resume **
    Activity_Resume called
    Error occurred on line: 198 (Main)
    java.lang.NullPointerException: Attempt to invoke interface method 'java.util.Iterator java.util.List.iterator()' on a null object reference
    at wifi.MLwifi$MLWifiScanner.listSavedNetworks(MLwifi.java:997)
    at com.msluk.net.siot_approach_data.main._activity_resume(main.java:542)
    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:710)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:339)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:249)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:139)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:166)
    at com.msluk.net.siot_approach_data.main.afterFirstLayout(main.java:108)
    at com.msluk.net.siot_approach_data.main.access$000(main.java:17)
    at com.msluk.net.siot_approach_data.main$WaitForLayout.run(main.java:80)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:6934)
    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:1404)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
    ** Activity (main) Pause, UserClosed = true **
    ** Service (starter) Destroy **
    SENTINEL_MSG_LIBCUTILS
    SENTINEL_MSG_LIBLOG

    I ran a very similar code snippet yesterday and it worked, but I modified it and started getting this error so I extracted these lines to make things simpler.

    Thanks

    Simon M
     
  2. Emme Developer

    Emme Developer Well-Known Member Licensed User

    Please, use CODE tag when you post a code.
    Have you Wifi enabled? You're getting a null object from this line
    Code:
    myAPlist = myScan.listSavedNetworks
    As i remember this happens when you have not wifi enabled
     
  3. SimonatMSL

    SimonatMSL Member Licensed User

    Thanks

    Sorry about the code tag.
     
  4. Ricky D

    Ricky D Well-Known Member Licensed User

    So add a try catch and toastmessage the user they need to turn on wifi in the catch
     
  5. SimonatMSL

    SimonatMSL Member Licensed User

    Thanks.

    It does seem a little odd to have to have to have the actual Wifi radio enabled to manage a memory resource. I want to give my users tha ability to see and eliminate entries which the phone might otherwise log on to (i.e. the phone is used on ships which often have open wifis and I want the users to be able to see and cleanse any instances where the user has logged in to these as apposed to our wifis located at the berths).
     
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