Android Question convert a single byte to string

Marco Maria Vilucchi · Aug 11, 2019

Hi all,
I need to convert a single byte to a string
I use this code to create the byte:

B4X:

    Dim b As Byte
    Dim wstr As String
    b = 23
    LogByte(b)
    b = SetBit(b, 0, False)
    LogByte(b)

(this is an Erel code)

The log is this:

B4X:

00010111
00010110

Now I want convert b to a string (wstr) :

B4X:

    wstr = BytesToString(b, 0, 1, "UTF8")
    LogByte(wstr)

but I have an error

B4X:

java.lang.ArrayIndexOutOfBoundsException: length=0; index=0
    at com.mamavi.slimup.main._activity_create(main.java:1974)
    at java.lang.reflect.Method.invoke(Native Method)
    at anywheresoftware.b4a.BA.raiseEvent2(BA.java:196)
    at com.mamavi.slimup.main.afterFirstLayout(main.java:104)
    at com.mamavi.slimup.main.access$000(main.java:17)
    at com.mamavi.slimup.main$WaitForLayout.run(main.java:82)
    at android.os.Handler.handleCallback(Handler.java:790)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:7000)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)

How can I solve?
Thanks in advance

Erel · Aug 11, 2019

There is no meaning to the code you posted. Please post an example of the input and the expected output.

emexes · Aug 11, 2019

Presumably BytesToString expects an Array of Bytes, not just a standalone Byte. Try:

B4X:

Dim BA() As Byte = Array As Byte(b)    'or = Array As Byte(b, b2, b3, b4...) for multiple bytes
wstr = BytesToString(BA, 0, 1, "UTF8")

Marco Maria Vilucchi · Aug 11, 2019

sorry I try to explain myself better
first of all, I repeat correct doce:

B4X:

Dim b As Byte
    Dim wstr As String
    b = 71
    LogByte(b)
    b = SetBit(b, 0, False)
    LogByte(b)

Sub LogByte(b As Byte)
    Log(NumberFormat2(Bit.ToBinaryString(Bit.And(0xff, b)), 8, 0, 0, False))
End Sub

The log is:

B4X:

01000111
01000110

that is:
71
70

Now I need simply have a string with "F" (that is 70)
I hope this time I was clear

emexes · Aug 11, 2019

B4X:

Dim IsThisTheAnswer As String = Chr(70)
Log("IsThisTheAnswer = " & IsThisTheAnswer)

gives log:

B4X:

IsThisTheAnswer = F

inakigarm · Aug 11, 2019

Marco Maria Vilucchi said:
sorry I try to explain myself better
first of all, I repeat correct doce:

B4X:

Dim b As Byte Dim wstr As String b = 71 LogByte(b) b = SetBit(b, 0, False) LogByte(b) Sub LogByte(b As Byte) Log(NumberFormat2(Bit.ToBinaryString(Bit.And(0xff, b)), 8, 0, 0, False)) End Sub

The log is:

B4X:

01000111 01000110

that is:
71
70

Now I need simply have a string with "F" (that is 70)
I hope this time I was clear

Asc(70) - Asc(71)

emexes · Aug 11, 2019

Or if you have multiple bytes, then:

B4X:

Dim BiggerAnswer As String = Chr(64 + 8) & Chr(96 + 5) & Chr(96 + 12) & Chr(96 + 12) & Chr(96 + 15)
Log("BiggerAnswer = " & BiggerAnswer)

gives log:

B4X:

BiggerAnswer = Hello

emexes · Aug 11, 2019

The first 128 Unicode characters are the 128 ASCII characters, eg Unicode character 70 is the same as ASCII character 70, ie both are an uppercase F.

Marco Maria Vilucchi · Aug 11, 2019

thanks all, really....

emexes · Aug 11, 2019

Still wondering where this is going, though...

Android Question convert a single byte to string

Marco Maria Vilucchi

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