Android Question Basics -- Strings, Objects and Types

[Steve Piehl]

I have been playing with this for quite awhile and not sure how to use the CallSubDelayedPlus2 routine. I have loaded the CallSubUtils class module and I am attempting to call a subroutine in the same module I am in (main).

I have already tried to review the tutorial on variables and objects and I am just not understanding something. I don't understand enough about Objects versus Strings. How do you convert from object to a string and vice versa?

My original subroutine "SendJobToServer" was setup to receive an arg as a "String" arg...not an "Object". The CallSubDelayedPlus2 routine requires that args be sent as Objects. I changed the arg to look for an object...but that doesn't seem to work. In the code snippet below, I attempt to pass the String arg "StatusUpdate" as an object to be used in the subroutine. Also I need this arg "JobName" to be a string. Do I have to use stringbuilder to get around the need for a string after passing it as an object? How do I pass it as an object?

Sub SendJobtoServer (JobName As Object)
    Log("SendJobtoServer, Job= "& JobName)
    Dim j As HttpJob
    j.Initialize(JobName, Me)
    j.Download(ServerLink & "/" & JobName)
    If JobName = "StatusUpdate" Then 
        ProgressDialogShow("Updating System Status...")
    Else
        ProgressDialogShow("Downloading report...")
    End If
End Sub

Sub SetSystem Status
    ...
    Dim Job2Send As Object
    Job2Send="StatusUpdate"
    Starter.csu.CallSubDelayedPlus2(Me,"SendJobtoServer",2000,Job2Send) '<---error object
End Sub

Any help is appreciated.

 

[Erel]

Starter.csu.CallSubDelayedPlus2(Me, "SendJobTo_Server", 2000, Array ("StatusUpdate")) 

Sub SendJobTo_Server (Name As String) 'tip: add an underscore to prevent the obfuscator from obfuscating the sub name
...
End Sub

 

[Steve Piehl]

Erel -- thanks for your reply. I made the changes you suggested.

I am still generating an error...now it appears that I can pass the variable to the SendJobTo_Server routine...but this routine is generating a similar error on the j.initialize line.

Sub SendJobTo_Server (JobName As String)

    Log("SendJobtoServer, Job= "& JobName)
    Dim j As HttpJob
    j.Initialize(JobName, Me)  '<---ERROR occurs here now (line 113)
    j.Download(ServerLink & "/" & JobName)
    If JobName = "StatusUpdate" Then
        ProgressDialogShow("Updating System Status...")
    Else
        ProgressDialogShow("Downloading report...")
    End If
End Sub

Here is the output from the debug log:

SendJobtoServer, Job= [Ljava.lang.Object;@6eb6977
Error occurred on line: 113 (Main)
java.lang.IllegalArgumentException: method anywheresoftware.b4a.samples.httputils2.httpjob._initialize argument 2 has type java.lang.String, got java.lang.Object[]
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.shell.Shell.runVoidMethod(Shell.java:753)
    at anywheresoftware.b4a.shell.Shell.raiseEventImpl(Shell.java:343)
    at anywheresoftware.b4a.shell.Shell.raiseEvent(Shell.java:247)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.ShellBA.raiseEvent2(ShellBA.java:134)
    at anywheresoftware.b4a.BA$2.run(BA.java:328)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:158)
    at android.app.ActivityThread.main(ActivityThread.java:7224)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

 

[KMatle]

Clear: You send an array. Jobname must be a string. So just convert it back to a string...

 

[DonManfred]

    Starter.csu.CallSubDelayedPlus3(Me, "SendJobTo_Server", 2000, Array As String("StatusUpdate"))

Sub SendJobTo_Server (param() As String)
    Dim jobname As String = param(0)
        Log("SendJobtoServer, Job= "& jobname)
    Dim j As HttpJob
    j.Initialize(jobname, Me)  '<---ERROR occurs here now (line 113): occurs no longer
    'j.Download(ServerLink & "/" & JobName)
    'If JobName = "StatusUpdate" Then
    '    ProgressDialogShow("Updating System Status...")
    'Else
    '    ProgressDialogShow("Downloading report...")
    'End If
End Sub

And the method you need to add to the CallSubUtils Class

Public Sub CallSubDelayedPlus3(Module As Object, SubName As String, Delay As Int, Arg() As String)
    PlusImpl(Module, SubName, Delay, Arg, True)
End Sub

** Service (starter) Create **
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
SendJobtoServer, Job= StatusUpdate
** Activity (main) Pause, UserClosed = false **
** Activity (main) Resume **

 

[Erel]

My code was wrong. See the tutorial: https://www.b4x.com/android/forum/threads/b4x-callsubplus-callsub-with-explicit-delay.60877/#content

It should be:

Starter.csu.CallSubDelayedPlus2(Me, "SendJobTo_Server", 2000, Array ("StatusUpdate")) 

Sub SendJobTo_Server (Args() As Object) 'tip: add an underscore to prevent the obfuscator from obfuscating the sub name
 Dim Name As String = Args(0)
End Sub

 

[Steve Piehl]

Thank you to everyone for your replies. I am beginning to understand how to convert objects to strings and vice versa.

I was missing the idea that you can pass an arg to a subroutine as an object and then re-define that object/item to another datatype on-the-fly. This is very useful information. Thanks again!