Acaia_android.java

package org.toto.lmlm;

import android.annotation.TargetApi;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.bluetooth.BluetoothGattService;
import android.bluetooth.BluetoothManager;
import android.bluetooth.BluetoothProfile;
import android.bluetooth.le.BluetoothLeScanner;
import android.bluetooth.le.ScanCallback;
import android.bluetooth.le.ScanFilter;
import android.bluetooth.le.ScanResult;
import android.bluetooth.le.ScanSettings;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Build;
import android.os.Handler;
import android.os.ParcelUuid;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;



@TargetApi(21)
public class MainScreen extends AppCompatActivity {

    private BluetoothAdapter mBluetoothAdapter;
    private int REQUEST_ENABLE_BT = 1;
    private Handler mHandler;
    private static final long SCAN_PERIOD = 10000;
    private BluetoothLeScanner mLEScanner;
    private ScanSettings settings;
    private List<ScanFilter> filters;
    private BluetoothGatt mGatt;
    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
    private boolean notificationInfoSent;

    private String SCALE_SERVICE_UUID = "00001820-0000-1000-8000-00805f9b34fb";
    private String SCALE_CHARACTERISTIC_UUID = "00002a80-0000-1000-8000-00805f9b34fb";

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main_screen);
        mHandler = new Handler();
        if (!getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE)) {
            Toast.makeText(this, "BLE Not Supported", Toast.LENGTH_SHORT).show();
            finish();
        }

        final BluetoothManager bluetoothManager =
                (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        mBluetoothAdapter = bluetoothManager.getAdapter();
    }


    @Override
    protected void onResume() {

        super.onResume();

        if (mBluetoothAdapter == null || !mBluetoothAdapter.isEnabled()) {
            Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
        }
        else {
            if (Build.VERSION.SDK_INT >= 21) {
                mLEScanner = mBluetoothAdapter.getBluetoothLeScanner();
                settings = new ScanSettings.Builder()
                        .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
                        .build();
                filters = new ArrayList<>();
                filters.add(
                        new ScanFilter
                                .Builder()
                                .setServiceUuid(ParcelUuid.fromString(SCALE_SERVICE_UUID))
                                .build()
                );
            }


            scanLeDevice(true);
        }
    }


    @Override
    protected void onPause() {

        super.onPause();
        if (mBluetoothAdapter != null && mBluetoothAdapter.isEnabled()) {
            scanLeDevice(false);
        }
    }


    @Override
    protected void onDestroy() {

        if (mGatt == null) {
            return;
        }

        mGatt.close();
        mGatt = null;
        super.onDestroy();
    }


    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {

        if (requestCode == REQUEST_ENABLE_BT) {
            if (resultCode == Activity.RESULT_CANCELED) {
                //Bluetooth not enabled.
                finish();
                return;
            }
        }

        super.onActivityResult(requestCode, resultCode, data);
    }


    private void scanLeDevice(final boolean enable) {

        if (enable) {
            mHandler.postDelayed(new Runnable() {
                @Override
                public void run() {
                    if (Build.VERSION.SDK_INT < 21) {
                        mBluetoothAdapter.stopLeScan(mLeScanCallback);
                    } else {
                        mLEScanner.stopScan(mScanCallback);

                    }
                }
            }, SCAN_PERIOD);

            if (Build.VERSION.SDK_INT < 21) {
                mBluetoothAdapter.startLeScan(mLeScanCallback);
            } else {
                mLEScanner.startScan(filters, settings, mScanCallback);
            }
        }
        else {
            if (Build.VERSION.SDK_INT < 21) {
                mBluetoothAdapter.stopLeScan(mLeScanCallback);
            } else {
                mLEScanner.stopScan(mScanCallback);
            }
        }
    }


    private ScanCallback mScanCallback = new ScanCallback() {

        @Override
        public void onScanResult(int callbackType, ScanResult result) {

            Log.i("callbackType", String.valueOf(callbackType));
            Log.i("result", result.toString());
            BluetoothDevice btDevice = result.getDevice();
            connectToDevice(btDevice);
        }


        @Override
        public void onBatchScanResults(List<ScanResult> results) {

            for (ScanResult sr : results) {
                Log.i("ScanResult - Results", sr.toString());
            }
        }


        @Override
        public void onScanFailed(int errorCode) {

            Log.e("Scan Failed", "Error Code: " + errorCode);
        }
    };


    private BluetoothAdapter.LeScanCallback mLeScanCallback =
            new BluetoothAdapter.LeScanCallback() {
                @Override
                public void onLeScan(final BluetoothDevice device, int rssi,
                                     byte[] scanRecord) {
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            Log.i("onLeScan", device.toString());
                            connectToDevice(device);
                        }
                    });
                }
            };

    public void connectToDevice(BluetoothDevice device) {

        if (mGatt == null) {
            mGatt = device.connectGatt(this, false, gattCallback);
            // will stop after first device detection
            scanLeDevice(false);
        }
    }


    private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {

            Log.i("onConnectionStateChange", "Status: " + status);
            switch (newState) {
                case BluetoothProfile.STATE_CONNECTED:
                    Log.i("gattCallback", "STATE_CONNECTED");
                    gatt.discoverServices();
                    break;

                case BluetoothProfile.STATE_DISCONNECTED:
                    Log.e("gattCallback", "STATE_DISCONNECTED");
                    break;

                default:
                    Log.e("gattCallback", "STATE_OTHER");
            }
        }


        private void sendMessage(int type, byte[] payload) {

            int cksum1 = 0;
            int cksum2 = 0;
            byte[] bytes = new byte[payload.length + 5];
            bytes[0] = (byte)0xef;
            bytes[1] = (byte)0xdd;
            bytes[2] = (byte)type;

            for (int i = 0; i < payload.length; i++) {
                bytes[i + 3] = payload[i];
                if (i % 2 == 0) {
                    cksum1 = (cksum1 + payload[i]) & 0xFF;
                }
                else {
                    cksum2 = (cksum2 + payload[i]) & 0xFF;
                }
            }

            bytes[payload.length + 3] = (byte)cksum1;
            bytes[payload.length + 4] = (byte)cksum2;

            BluetoothGattCharacteristic characteristic = mGatt.getService(UUID.fromString(SCALE_SERVICE_UUID)).getCharacteristic(UUID.fromString(SCALE_CHARACTERISTIC_UUID));
            characteristic.setValue(bytes);
            mGatt.writeCharacteristic(characteristic);
        }


        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {

            BluetoothGattService service = gatt.getService(UUID.fromString(SCALE_SERVICE_UUID));
            Log.i("onServicesDiscovered", service.toString());
            BluetoothGattCharacteristic characteristic = service.getCharacteristic(UUID.fromString(SCALE_CHARACTERISTIC_UUID));
            gatt.setCharacteristicNotification(characteristic, true);

            BluetoothGattDescriptor descriptor = characteristic.getDescriptors().get(0);
            descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
            gatt.writeDescriptor(descriptor);

            // Run heartbeat every 3 seconds to keep connection alive
            scheduler.scheduleAtFixedRate(() -> {
                byte[] payload = {0x02,0x00,0x02,0x00};
                sendMessage(0, payload);
            }, 2, 3, TimeUnit.SECONDS);
        }

        @Override
        // Characteristic notification
        public void onCharacteristicChanged(BluetoothGatt gatt,
                                            BluetoothGattCharacteristic characteristic) {

            StringBuilder sb = new StringBuilder();
            for (byte b : characteristic.getValue()) {
                sb.append(String.format("%02X ", b));
            }
            Log.i("onCharacteristicRead", sb.toString());

            if (characteristic.getValue()[2] == 7) {
                byte[] payload = {0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d,0x2d};
                sendMessage(11, payload);
            }

            if (characteristic.getValue()[2] == 8 && !notificationInfoSent) {
                byte[] payload = {0x09,0x00,0x01,0x01,0x02,0x02,0x05,0x03,0x04};
                sendMessage(12, payload);

                notificationInfoSent = true;
            }
        }


        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic characteristic,
                                         int status) {

            Log.i("onCharacteristicRead", characteristic.toString());
            gatt.disconnect();
        }
    };
}