Problems converting numbers from strings

Stulish · Nov 22, 2012

Hi,

My app transfers data via serial communications, the data is in a string format.

my app seems to run ok but at times it will sometimes throw up and invalid double error, this normally happens if some of the sentances have not been sent and the the fields are blank.

java.lang.NumberFormatException: Invalid double: ""

at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.parseDouble(StringToReal.java:248)
at java.lang.Double.parseDouble(Double.java:295)
at android.lishsoft.smids.main._popnmea(main.java:1047)
at android.lishsoft.smids.main._recievetimer_tick(main.java:1233)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at anywheresoftware.b4a.BA.raiseEvent2(BA.java:165)
at anywheresoftware.b4a.objects.Timer$TickTack.run(Timer.java:103)
at android.os.Handler.handleCallback(Handler.java:605)
at android.os.Handler.dispatchMessage(Handler.java:92)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4517)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
at dalvik.system.NativeStart.main(Native Method)
java.lang.NumberFormatException: Invalid double: ""

My understanding was if i have a string that contains "00.03" in a variable SomeString

and then i create a variable SomeDouble by:

B4X:

Dim SomeDouble as double

when i use the following it should convert the string to a double automatically:

B4X:

SomeDouble = SomeString

is this thinking correct?

what is the outcome if the string contains nothing?

i have tried to catch the error using an if statement to say

B4X:

if SomeString<>"" then SomeDouble=SomeString

basically if the string contains nothing then do not do the conversion, but i still get the error

nothing seems to work

mc73 · Nov 22, 2012

The returning string seems to be not an empty string, but the "". Anyway. perhaps trying this will solve the problem, though I don't recommend using it, but find the real cause:

B4X:

try
     SomeDouble=SomeString
catch
     SomeDouble=0
end try

Stulish · Nov 22, 2012

thanks, i have managed to sort it out i used the ISNumber() command to see if the string could be converted to a number first.

no errors so far

klaus · Nov 22, 2012

Have you tied this:

B4X:

If IsNumber(SomeString) = True Then
   SomeDouble = SomeString
Else
   Msgbox("Not a number", "ERROR")
End If

Best regards.

EDIT: Just a bit too late.

Stulish · Nov 22, 2012

Thanks Klause

shaxboz · Mar 28, 2014

Hi! I have problem with cinverting string to int.
I have two variables
I as int
S as string
s="150"
when I write I=s some devices showing error message "numberformat exception"
How can I convert string to int?

eps · Mar 28, 2014

You should start another thread..

Of course S and s are different... sort that bit out first.

shaxboz · Mar 28, 2014

not S as string, it is like s as string

DonManfred · Mar 28, 2014

>when I write I=s some devices showing error message "numberformat exception"

I dont see any code which is using numberformat!?

Post more relevant code and describe it more clearly. It´s hard to help with getting incomplete informations...

Maybe export your project as zip and upload it here... We then can have a look at it

shaxboz · Mar 28, 2014

ok
Dim ochkolari As String
Dim myochko As Int
Dim TextReader1 As TextReader
TextReader1.Initialize(File.OpenInput(File.DirInternal, "css.txt"))
ochkolari = TextReader1.ReadLine
TextReader1.Close
myochko=ochkolari

eps · Mar 28, 2014

shaxboz said:
not S as string, it is like s as string

Please post the code that you are having trouble with, what you have posted is incorrect.

and use [ code ] [ /code] tags as well, otherwise it makes it difficult to read and therefore difficult to help.

eps · Mar 28, 2014

What does ochkolari hold before the last statement?

shaxboz · Mar 28, 2014

noting, it is only begining...

shaxboz · Mar 28, 2014

I will read to ochkolari from file. there is written only 150 in a file

eps · Mar 28, 2014

shaxboz said:
noting, it is only begining...

but you've just assigned it a value with this statement :

B4X:

ochkolari = TextReader1.ReadLine

So what does it get assigned?

DonManfred · Mar 28, 2014

So you want to convert an empty string to an number????

B4X:

If IsNumber(ochkolari) = True Then
  myochko= ochkolari
Else
  myochko=0
  Msgbox("Not a number", "ERROR")
End If

eps · Mar 28, 2014

Did the read work? You need to either toast message show that variable or log it or at least check it, don't assume that it's worked..

DonManfred · Mar 28, 2014

B4X:

ochkolari = TextReader1.ReadLine
log("String from file: -->"&ochkolari&"<--")

What does this command output in log??

And to get more detailed informations... What´s the content of css.txt? Post this file here too...

eps · Mar 28, 2014

There's probably an issue here with file encoding...

shaxboz · Mar 28, 2014

yes ofcourse, there will be problem with my file.
Thanks
But I have other question.
Now I am writing my config files to internal.
I am new, so I don`t know which is good write to internal or external storage?

Problems converting numbers from strings

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