From version 6.4.2 there is added functionality to set custom callback using the SDK, this can be done by using the SIDNetData class. After setting the other settings in this class then call the methodsetCallBackUrl as in the example below
If the call back URL is not set from the SDK it will always default to the setting on the backend.
SIDNetData data = new SIDNetData();
....//other SIDNetData settings
data.setCallBackUrl(https://example.com/callback);
SETTING ENVIRONMENTS
SIDNetData data = new SIDNetData();
data.setAuthUrl(AUTH_URL);
data.setPartnerUrl(PARTNER_URL);
data.setPartnerPort(PARTNER_PORT);
data.setLambdaUrl(LAMBDA_URL);
data.setSidAddress(SID_ADDRESS);
data.setSidPort(SID_PORT);
data.setCallBackUrl(https://example.com/callback);
SIDConfig.Builder builder = new SIDConfig.Builder(this);
....
builder.setSmileIdNetData(data)
....