Android Question returning ResumableSub from ResumableSub

[Robert Valentino]

I am converting one of my apps to use wait for / ResumableSub.

And I came across an interesting problem where I had routines returning a return

This is not the code but this is an easy way of showing:

Spoiler: ResumableSub

Sub Activity_Resume
    CallSubDelayed(Me, "TestResumableSub")
  
End Sub

Public  Sub TestResumableSub
            Log("TestResumableSub")
          
            Wait for (TestResumable2Sub) Complete(RC As Boolean)
End Sub

public     Sub TestResumable2Sub As ResumableSub
            Log("TestResumableSub2")
  
            Return TestResumableSub3
End Sub

public     Sub TestResumableSub3 As ResumableSub
            Log("TestResumableSub3")
  
            Return TestResumableSub4
End Sub

public     Sub TestResumableSub4 As ResumableSub
            Log("TestResumableSub4")
  
            Sleep(0)
          
            Return True
End Sub

The above generates this output and error

Spoiler: ResumableSub Output

** Activity (main) Pause, UserClosed = false **
*** Service (starter) Create ***
** Service (starter) Start **
** Activity (main) Create, isFirst = true **
** Activity (main) Resume **
TestResumableSub
TestResumableSub2
TestResumableSub3
TestResumableSub4
main$ResumableSub_TestResumableSubresume (java line: 443)
java.lang.ClassCastException: anywheresoftware.b4a.keywords.Common$ResumableSubWrapper cannot be cast to java.lang.Boolean
    at b4a.example.main$ResumableSub_TestResumableSub.resume(main.java:443)
    at anywheresoftware.b4a.BA.checkAndRunWaitForEvent(BA.java:250)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:190)
    at anywheresoftware.b4a.BA.raiseEvent(BA.java:176)
    at anywheresoftware.b4a.keywords.Common$14.run(Common.java:1761)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:145)
    at android.app.ActivityThread.main(ActivityThread.java:6939)
    at java.lang.reflect.Method.invoke(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:372)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1404)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1199)
** Activity (main) Pause, UserClosed = false **

Now I understand the problem

Spoiler: ResumableSub Declare Return Type

Wait for (TestResumable2Sub) Complete(RC As Boolean)

that I am not declaring the return type. And there are two fixes for this either I can change the RC as Boolean to RC as ResumableSub or
for each return I can do a wait for(x...) complete(RC as Boolean) and then return RC

I just found it surprising that returning a boolean that resumablesub could not propergate the return type backwards

BobVal

 

[DonManfred]

[B4X] Resumable subs that return values (ResumableSub)

Remember that that a call to Sleep or Wait For in a resumable sub causes the code flow to return to the parent. Example: Sub Button1_Click Sum(1, 2) Log("after sum") End Sub Sub Sum(a As Int, b As Int) Sleep(100) 'this will cause the code flow to return to the parent Log(a + b) End Sub...

www.b4x.com

 

[Robert Valentino]

??Confused by your answer. Didn't say I know how to use it, but I came across this while doing a search and replace type of conversion to my code.

 

[Robert Valentino]

I guess what I should have said, is I would have thought that the compiler would have given me a warning on this rather then the program crashing