Android Question getting/putting booleans in maps - must cast to boolean?

[Dave O]

Hi all,

I often use maps (with readMap and writeMap) to load and save data.

However, I just noticed that if I save a boolean value to a map:

settingsMap.Put("sound", True)

...and load it later with:

settingsMap.Get("sound")

...it appears to work:

Log("sound = " & settingsMap.Get("sound"))  'returns "sound = true"

...but when I test it, it fails:

If settingsMap.Get("sound") = True Then        'returns false

It only seems to work if I explicitly cast it to a boolean:

If settingsMap.Get("sound").As(Boolean) = True Then        'returns true as intended

I found this confusing, thinking at first that there must be implicit casting happening. The "put" seemed to implicitly cast True to "true", and the "get" returned "true" (no surprise) but the expression didn't implicitly cast "true" to True.

I wonder if this is one of those where I should write the known type first in the expression?

If True = settingsMap.Get("sound") Then

I'm guessing this may trip up others, so I hope this helps.

 

[DonManfred]

...but when I test it, it fails

it is expected as the loaded value IS a STRING

Use B4XEncryption library and

    Dim ser As B4XSerializator
   
    Dim m As Map
    m.Initialize
    m.Put("Bool",True)
    Dim bytes() As Byte = ser.ConvertObjectToBytes(m)
    File.WriteBytes(File.DirInternal,"data.map",bytes)

    Dim bytesnew() As Byte = File.ReadBytes(File.DirInternal,"data.map")
   
    Dim mapnew As Map = ser.ConvertBytesToObject(bytesnew)
    If mapnew.Get("Bool") = True Then
        Log($"TRUE :D"$)
    Else
        Log($"Dammit..."$)
    End If

 

[aeric]

How to correctly compare values? (get expected results and avoid crashes)

(This thread is a spin-off from https://www.b4x.com/android/forum/threads/1-1.117065/, which is a really interesting thread that I encourage people to read in full.) I mean, if the compiler sees a comparison where one side is an object and the other is not, and its safer to put it on the right...

www.b4x.com