Android Open Source - BLEService H R Demo Activity

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License

The source code is released under:
Copyright (c) 2014, Ratio LLC. All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: ...
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Java Source Code

package org.bluetooth.bledemo;
/*from   w ww . j a  va  2  s  .c o  m*/
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.UUID;

import android.os.Bundle;
import android.os.Handler;
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.content.Context;
import android.content.pm.PackageManager;
import android.view.MenuItem;
import android.widget.EditText;
import android.widget.TextView;
import android.support.v4.app.NavUtils;

/* this activity's purpose is to show how to use particular type of devices in easy and fast way */
public class HRDemoActivity extends Activity {
  
  private Handler mHandler = null;
  private BluetoothManager mBTManager = null;
  private BluetoothAdapter mBTAdapter = null;
  private BluetoothDevice  mBTDevice = null;
  private BluetoothGatt    mBTGatt = null;
  private BluetoothGattService        mBTService = null;
  private BluetoothGattCharacteristic mBTValueCharacteristic = null;
  // UUDI od Heart Rate service:
  final static private UUID mHeartRateServiceUuid = BleDefinedUUIDs.Service.HEART_RATE;
  final static private UUID mHeartRateCharacteristicUuid = BleDefinedUUIDs.Characteristic.HEART_RATE_MEASUREMENT;
  
  private EditText mConsole = null;
  private TextView mTextView  = null;
  
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_hrdemo);
    mConsole = (EditText) findViewById(R.id.hr_console_item);
    log("Creating activity");
    
    // Show the Up button in the action bar.
    getActionBar().setDisplayHomeAsUpEnabled(true);
    setTitle("Heart Rate Demo");
    mConsole = (EditText) findViewById(R.id.hr_console_item);
    mTextView = (TextView) findViewById(R.id.hr_text_view);

    mHandler = new Handler();
    log("Activity created");
  }

  @Override
  public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case android.R.id.home:
      NavUtils.navigateUpFromSameTask(this);
      return true;
    }
    return super.onOptionsItemSelected(item);
  }

  @Override
  protected void onResume() {
    super.onResume();
    log("Resuming activity");
    
    // first check if BT/BLE is available and enabled
    if(initBt() == false) return;
    if(isBleAvailable() == false) return;
    if(isBtEnabled() == false) return;
    
    // then start discovering devices around
    startSearchingForHr();
    
    log("Activity resumed");
  }
  
  @Override
  protected void onPause() {
    super.onPause();
    
    disableNotificationForHr();
    disconnectFromDevice();
    closeGatt();
  };

  private boolean initBt() {
    mBTManager = (BluetoothManager)getSystemService(Context.BLUETOOTH_SERVICE);
    if(mBTManager != null) mBTAdapter = mBTManager.getAdapter();
    
    return (mBTManager != null) && (mBTAdapter != null);
  }
  
  private boolean isBleAvailable() {
    log("Checking if BLE hardware is available");
    
    boolean hasBle = getPackageManager().hasSystemFeature(PackageManager.FEATURE_BLUETOOTH_LE);
    if(hasBle && mBTManager != null && mBTAdapter != null) {
      log("BLE hardware available");
    }
    else {
      log("BLE hardware is missing!");
      return false;
    }
    return true;
  }
  
  private boolean isBtEnabled() {
    log("Checking if BT is enabled");
    if(mBTAdapter.isEnabled()) {
      log("BT is enabled");
    }
    else {
      log("BT is disabled. Use Setting to enable it and then come back to this app");
      return false;
    }
    return true;
  }

  private void startSearchingForHr() {
    // we define what kind of services found device needs to provide. In our case we are interested only in
    // Heart Rate service
    final UUID[] uuids = new UUID[] { mHeartRateServiceUuid };
    mBTAdapter.startLeScan(uuids, mDeviceFoundCallback);
    // results will be returned by callback
    log("Search for devices providing Heart Rate service started");
    
    // please, remember to add timeout for that scan
    Runnable timeout = new Runnable() {
            @Override
            public void run() {
        if(mBTAdapter.isDiscovering() == false) return;
        stopSearchingForHr();  
            }
        };
        mHandler.postDelayed(timeout, 10000); //10 seconds    
  }

  private void stopSearchingForHr() {
    mBTAdapter.stopLeScan(mDeviceFoundCallback);
    log("Searching for devices with Heart Rate service stopped");
  }
  
  private void connectToDevice() {
    log("Connecting to the device NAME: " + mBTDevice.getName() + " HWADDR: " + mBTDevice.getAddress());
    mBTGatt = mBTDevice.connectGatt(this, true, mGattCallback);
  }
  
  private void disconnectFromDevice() {
    log("Disconnecting from device");
    if(mBTGatt != null) mBTGatt.disconnect();
  }
  
  private void closeGatt() {
    if(mBTGatt != null) mBTGatt.close();
    mBTGatt = null;
  }
  
  private void discoverServices() {
    log("Starting discovering services");
    mBTGatt.discoverServices();
  }
  
  private void getHrService() {
    log("Getting Heart Rate Service");
    mBTService = mBTGatt.getService(mHeartRateServiceUuid);
    
    if(mBTService == null) {
      log("Could not get Heart Rate Service");
    }
    else {
      log("Heart Rate Service successfully retrieved");
      getHrCharacteristic();
    }
  }
  
  private void getHrCharacteristic() {
    log("Getting Heart Rate Measurement characteristic");
    mBTValueCharacteristic = mBTService.getCharacteristic(mHeartRateCharacteristicUuid);
    
    if(mBTValueCharacteristic == null) {
      log("Could not find Heart Rate Measurement Characteristic");
    }
    else {
      log("Heart Rate Measurement characteristic retrieved properly");
      enableNotificationForHr();
    }
  }
  
  private void enableNotificationForHr() {
    log("Enabling notification for Heart Rate");
        boolean success = mBTGatt.setCharacteristicNotification(mBTValueCharacteristic, true);
        if(!success) {
          log("Enabling notification failed!");
          return;
        }

        BluetoothGattDescriptor descriptor = mBTValueCharacteristic.getDescriptor(BleDefinedUUIDs.Descriptor.CHAR_CLIENT_CONFIG);
        if(descriptor != null) {
          descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
          mBTGatt.writeDescriptor(descriptor);
          log("Notification enabled");
        }    
        else {
          log("Could not get descriptor for characteristic! Notification are not enabled.");
        }
  }

  private void disableNotificationForHr() {
    log("Disabling notification for Heart Rate");
        boolean success = mBTGatt.setCharacteristicNotification(mBTValueCharacteristic, false);
        if(!success) {
          log("Disabling notification failed!");
          return;
        }

        BluetoothGattDescriptor descriptor = mBTValueCharacteristic.getDescriptor(BleDefinedUUIDs.Descriptor.CHAR_CLIENT_CONFIG);
        if(descriptor != null) {
          descriptor.setValue(BluetoothGattDescriptor.DISABLE_NOTIFICATION_VALUE);
          mBTGatt.writeDescriptor(descriptor);
          log("Notification disabled");
        }    
        else {
          log("Could not get descriptor for characteristic! Notification could be still enabled.");
        }
  }  
  
  private void getAndDisplayHrValue() {
      byte[] raw = mBTValueCharacteristic.getValue();
      int index = ((raw[0] & 0x01) == 1) ? 2 : 1;
      int format = (index == 1) ? BluetoothGattCharacteristic.FORMAT_UINT8 : BluetoothGattCharacteristic.FORMAT_UINT16;
      int value = mBTValueCharacteristic.getIntValue(format, index);
      final String description = value + " bpm";

      runOnUiThread(new Runnable() {
      @Override
      public void run() {
        mTextView.setText(description);
      }
      });
  }
  
    private BluetoothAdapter.LeScanCallback mDeviceFoundCallback = new BluetoothAdapter.LeScanCallback() {
        @Override
        public void onLeScan(final BluetoothDevice device, final int rssi, final byte[] scanRecord) {
          // here we found some device with heart rate service, lets save it:
          HRDemoActivity.this.mBTDevice = device;
          log("Device with Heart Rate service discovered. HW Address: "  + device.getAddress());
          stopSearchingForHr();
          
          connectToDevice();
        }
    };  
  
    /* callbacks called for any action on HR Device */
    private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            if (newState == BluetoothProfile.STATE_CONNECTED) {
              log("Device connected");
              discoverServices();
            }
            else if (newState == BluetoothProfile.STATE_DISCONNECTED) {
              log("Device disconnected");
            }
        }

        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
          if(status == BluetoothGatt.GATT_SUCCESS) {
            log("Services discovered");
            getHrService();
          }
          else {
            log("Unable to discover services");
          }
        }

        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt,
                                            BluetoothGattCharacteristic characteristic)
        {
          if(characteristic.equals(mBTValueCharacteristic)) {
            getAndDisplayHrValue();
          }
        }       
        
        /* the rest of callbacks are not interested for us */
        
        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic characteristic,
                                         int status) {}


        
        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {};
        
        @Override
        public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) {};
    };
     
  
  // put new logs into the UI console
  private void log(final String txt) {
    if(mConsole == null) return;
    
    final String timestamp = new SimpleDateFormat("yyyy.MM.dd HH:mm:ss.SSS").format(new Date());
    runOnUiThread(new Runnable() {
      @Override
      public void run() {
        mConsole.setText(timestamp + " : " + txt + "\n" + mConsole.getText());
      }    
    });
  }
}
Java Source Code List
