Android Question NullPointerException on xui.CreatePanel

[AHilberink]

Hi,

Can someone tell me why I got "java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.ref.Reference.get()' on a null object reference"?

#Region  Service Attributes
    #StartAtBoot: False
    #ExcludeFromLibrary: True
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Dim Interval As Int:                Interval=1 'om de 5 minuten
    Private xui As XUI
    Dim Teller
End Sub

Sub Service_Create
    'This is the program entry point.
    'This is a good place to load resources that are not specific to a single activity.
    

End Sub

Sub Service_Start (StartingIntent As Intent)
    Log("Gedaan")
    StartServiceAtExact(Me, DateTime.Now + Interval * DateTime.TicksPerMinute, True)
    TellerNotification
    Service.StopAutomaticForeground 'Call this when the background task completes (if there is one)
End Sub

Sub Service_TaskRemoved
    'This event will be raised when the user removes the app from the recent apps list.
End Sub

'Return true to allow the OS default exceptions handler to handle the uncaught exception.
Sub Application_Error (Error As Exception, StackTrace As String) As Boolean
    Return True
End Sub

Sub Service_Destroy

End Sub

Sub TellerNotification
    Log("1")
    Dim p As Panel
    Log("1a")
    p = xui.CreatePanel("")
    Log("1b")
    p.SetLayoutAnimated(0, 0, 0, 24dip, 24dip)
    Log("2")
    Dim cvs As B4XCanvas
    cvs.Initialize(p)
    Log("3")
    Dim n As NB6
    Teller=Teller+1
    n.Initialize("default", Application.LabelName, "DEFAULT")
    Log("4")
    n.OnlyAlertOnce(True)
    Log("5")
    cvs.ClearRect(cvs.TargetRect)
    Log("6")
    cvs.DrawText(Teller, cvs.TargetRect.Width / 2, cvs.TargetRect.Height - 5dip, xui.CreateDefaultBoldFont(20), xui.Color_White, _
         "CENTER")
    Log("7")
    cvs.Invalidate
    Log("8")
    n.SmallIcon(cvs.CreateBitmap)
    Log("9")
    Dim Notification As Notification = n.Build("CountDownNotification", "...", "", "")
    Log("10")
    Notification.Notify(1)
    Log("11")
    cvs.Release
    Log("12")
End Sub

It seems to happen on "p = xui.CreatePanel("").
The complete message is:

Gedaan
1
1a
trigger_tellernotification (java line: 195)
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.Object java.lang.ref.Reference.get()' on a null object reference
 at anywheresoftware.b4a.objects.B4XViewWrapper$XUI.CreatePanel(B4XViewWrapper.java:704)
 at b4a.example.trigger._tellernotification(trigger.java:195)
 at b4a.example.trigger._service_start(trigger.java:171)
 at java.lang.reflect.Method.invoke(Native Method)
 at anywheresoftware.b4a.BA.raiseEvent2(BA.java:191)
 at anywheresoftware.b4a.BA.raiseEvent(BA.java:171)
 at b4a.example.trigger.handleStart(trigger.java:100)
 at b4a.example.trigger.access$000(trigger.java:8)
 at b4a.example.trigger$2.run(trigger.java:80)
 at android.os.Handler.handleCallback(Handler.java:808)
 at android.os.Handler.dispatchMessage(Handler.java:101)
 at android.os.Looper.loop(Looper.java:166)
 at android.app.ActivityThread.main(ActivityThread.java:7425)
 at java.lang.reflect.Method.invoke(Native Method)
 at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:245)
 at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:921)

Thanks.

Best regards,
André

 

[sorex]

I never used that method but I usually use this method

Dim px As B4XView
Dim p As Panel
p.Initialize("")
px=p
px.SetLayoutAnimated(0, 0, 0, 24dip, 24dip)

maybe the xui.createpanel() method allow you to do it in 1 command without the need to create the p panel first? I need to test that.

 

[klaus]

Two problems:

1. From the help:
xui.CreatePanel

Method

Creates a Panel (or Pane in B4J).
Note that the panel created will clip its child views.
In B4A, this method can only be called from an Activity context.

You cannot defin views in a Service.

2. When you use xui.CreatePanel("")
You must declare the Panel as B4XView!
Dim p As B4XView

@sorex

maybe the xui.createpanel() method allow you to do it in 1 command without the need to create the p panel first?

Yes !