GetExtra

[leongcc]

I use the same key for HasExtra() and GetExtra().
HasExtra() retuens True but GetExtra() returns null, that is MacObject is null.
Any advice?

Sub BroadCastReceiver_OnReceive (Action As String,  i As  Object)   
    Dim  intnt As  Intent
    intnt = i
    Log(intnt)
    Log(intnt.ExtrasToString)

    Dim MacObject as Object
    If (intnt.HasExtra("android.bluetooth.device.extra.DEVICE")) Then
         MacObject = intnt.GetExtra("android.bluetooth.device.extra.DEVICE")
         Log ("MacObject: " & MacObject)
    End If
End Sub

 

[Erel]

This means that the Null value was sent with the above key.

 

[leongcc]

The values are not null.
The Log of the intent show both the keys and the values.
Please see the comment directly below the Log statements.

 

[Erel]

What is the output of Log("MacObject: " & MacObject) ?

 

[leongcc]

I modified the codes to include the statement,
Log ("MacObject: " & MacObject).
The Log is as follows

(Intent)Intent { act=android.bluetooth.device.action.PAIRING_REQUEST fla=0x10 (has extras) }
Bundle[{android.bluetooth.device.extra.DEVICE=00:12:3E:00:16:65, android.bluetooth.device.SECURE=true, android.bluetooth.device.PAIRING_VARIANT=0}]
MacObject: null

 

[Erel]

The bundled value is not "serializable". You will not be able to fetch it with GetExtra.

 

[leongcc]

So HasExtra() is able to recognize the key in the Bundle but GetExtra() is not able to recognize the value that comes after, because the value is not "serializable".
Could you elaborate please?

 

[Erel]

Yes. GetExtra can only retrieve Java serializable objects.

You should use reflection and call Intent.getParcelableExtra.

 

[leongcc]

I am not familair with B4A Reflection, could give me an example how Reflection codes look like for Intent.getParcelableExtra()

 

[Erel]

The question is what do you plan to do with the returned object?

 

[leongcc]

Thanks for you reply.
My app is already working well using B4A BluetoothAdmin and BtSerial but I have to implement a special requirement.

Using the extra value from intent, I want to create a android.bluetooth.BluetoothDevice then access an internal method, setPin(). In Java I would do this:


BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(intent.getParcelableExtra(..))
device.setPin("1234")


I am not sure about B4A Reflection but I think I need it to get this done, and there is a good chance I will mess things up by reflecting BluetoothDevice because BluetoothDevice is a thin wrapper that serves android.bluetooth.BluetoothAdapter that is managed by B4A BluetoothAdmin. Do you think so?

Aternatively, I can write all Bluetooth stuff in Java and put it in a B4A library.

I appreciate some advice.

 

[Erel]

Note that setPin is a hidden API. You will need to call it with Reflection in Java.

I recommend you to create a small library with the required Java code.

 

[leongcc]

Just to inform that I wrote a Java class and convert it to B4A library.
Now my Android app can programmatically bond(pair) with bluetooth devices.

 

[walterf25]

Bluetooth Library

Hi there, can you share that library you created, i'm sure it will be helpful to a lot of us in here :icon_clap:


Cheers,
Walter

 

[leongcc]

The library is BtAutoPair in Forum-Additioanl Library.

 

[walterf25]

Bluetooth and Microcontroller

Thank you so much buddy, you're the man!