How to receive array data sent from custom characteristic to application on Android Studio

RE: How to receive array data sent from custom characteristic to application on Android Studio

Tai — Tue, 18 Jun 2019 18:03:55 GMT

Thanks for your reply, Simonr!

RE: How to receive array data sent from custom characteristic to application on Android Studio

Simonr — Tue, 18 Jun 2019 11:38:12 GMT

Glad you were able to figure out your initial problem.

The sd_ble_gatts_value_set function() takes in a ble_gatts_value_t pointer which has a pointer p_value to a uint8_t array. You can, therefore, typecast your struct to an uint8_t array and send it with the sd_ble_gatts_value_set() function. The attribute value offset parameter can be used to specify which parts of the attribute that you want to change. This can be useful if you only want to change a certain part of the characteristic.

Documentation can be found here.

Best regards,

Simon

RE: How to receive array data sent from custom characteristic to application on Android Studio

Tai — Mon, 17 Jun 2019 16:22:50 GMT

Well, I fixed that problem!

The issue stemmed from the size of characteristic. I changed from 1 byte to 10 bytes (image blow), and it worked. Hope it is helpful for someone struggling with this tho.

Moreover, instead of using the function data.getIntValue() in the Android application, I used data.getValue() which returns a byte array that is array data I supposed to receive from BLE server.

Last modification is to remove the portion of code which I supposed to use to update the value whenever some changes in my characteristic happen.

I'm still confused about the function of sd_ble_gatts_value_set(). How should it be used properly? Dose that act like whenever updating value from client (our phone..) to server, this function will be called?

Thanks,