I2C receive data

[Prandov]

I successfully tested I2CExample.java!

Now I'm trying to receive data from an I2C device (SGP30 CO2 sensor)
I created a wrapper for my I2C device as suggested in readme.md

To receive data from an I2C device: device.ask() requires a listener receive the data.
I'm struggling to implement this listener,
Is there an example using device.ask() ?

Thanks

[kurbatov]

Please, find the example of an I2C wrapper in this file https://github.com/kurbatov/firmata4j/blob/master/src/main/java/org/firmata4j/ssd1306/SSD1306.java
You don't have to implement I2CDevce interface as the library already does so in FirmataI2CDevice.

[Prandov]

Many thanks for the reply!

So SSD1306.java uses device.tell from FirmataI2CDevice.java (implementing the I2CListener.java interface)?

From SSD1306.java
227 device.tell(Arrays.copyOfRange(command, i, i + 2));

I don't have to use implements I2CListener at the top of my class since it is implemented in FirmataI2CDevice.java ?
Then I'm unsure how to assign the listener to receive the reply:

From FirmataI2CDevice.java :
77 public void ask(byte responseLength, I2CListener listener) throws IOException {
and
82 public void ask(int register, byte responseLength, I2CListener listener) throws IOException {

Is the listener created by the library or do I have to create it?

[kurbatov]

Using ask will do if you want to receive data from the device only once. In case you want react to a continuous stream of events from the device, there is subscribe method that takes a listener which you have to implement writing handling logic in there.