how to define SampleGattAttributes in the following code?

public final static UUID UUID_HEART_RATE_MEASUREMENT =
                UUID.fromString(SampleGattAttributes.HEART_RATE_MEASUREMENT);

SampleGattAttributes, appears in red colour,means unresolved symbol. How to define this?

I hope this will work for you.

Add SampleGattAttributes class in your package given below and import class.

import java.util.HashMap;

    public class SampleGattAttributes {
        private static HashMap<String, String> attributes = new HashMap();
        public static String HEART_RATE_MEASUREMENT = "00002a37-0000-1000-8000-00805f9b34fb";
       static {
            // Sample Services.
            attributes.put("0000180d-0000-1000-8000-00805f9b34fb", "Heart Rate Service");
            // Sample Characteristics.
            attributes.put(HEART_RATE_MEASUREMENT, "Heart Rate Measurement");
        }
    }