Android和蓝牙低功耗（BLE）

Question

我正在努力从自定义蓝牙低能耗设备读取/发送数据。 我正在使用Microchip RN4020蓝牙模块。

我发现的每个教程或示例都说明了如何将您的移动应用程序连接到设备，但没有找到与之实际交互的方法。 结果，这正是我可以和不能使用我的应用程序执行的操作。

对于存在的每个特征，我都执行以下操作：

gatt.readCharacteristic(services.get(i).getCharacteristics().get(j));

这是我打印值时的结果：

getStringValue= Mobi_F934��
getStringValue= null
getStringValue= ����d���

getStringValue= 001EC030F934
getStringValue= 2.1
getStringValue= 1.10
getStringValue= 1.10
getStringValue= Microchip
getStringValue= RN4020

getStringValue= 
getStringValue=

我不知道这是否重要...

如何读取从BLE设备发送的数据？

编辑：我的Android代码

    @TargetApi(21)
public class MainActivity extends ActionBarActivity {
    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;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

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

        // Initializes Bluetooth adapter
        final BluetoothManager bluetoothManager =
                (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
        mBluetoothAdapter = bluetoothManager.getAdapter();

    }

    @Override
    protected void onResume() {
        super.onResume();
        // Ensures Bluetooth is available on the device and it is enabled. If not,
        // displays a dialog requesting user permission to enable Bluetooth.

        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<ScanFilter>();
            }
            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.e("callbackType", "MAX " + String.valueOf(callbackType));
            Log.e("result", "MAX " + result.toString());
            BluetoothDevice btDevice = result.getDevice();
            connectToDevice(btDevice);
        }

        @Override
        public void onBatchScanResults(List<ScanResult> results) {
            for (ScanResult sr : results) {
                Log.e("ScanResult - Results", "MAX " + sr.toString());
            }
        }

        @Override
        public void onScanFailed(int errorCode) {
            Log.e("Scan Failed", "MAX " + "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.e("onLeScan", "MAX " + device.toString());
                            connectToDevice(device);
                        }
                    });
                }
            };

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

    private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            Log.e("onConnectionStateChange", "MAX " + "Status: " + status);
            switch (newState) {
                case BluetoothProfile.STATE_CONNECTED:
                    Log.e("gattCallback", "MAX " + "STATE_CONNECTED");
                    gatt.discoverServices();
                    break;
                case BluetoothProfile.STATE_DISCONNECTED:
                    Log.e("gattCallback", "MAX " + "STATE_DISCONNECTED");
                    break;
                default:
                    Log.e("gattCallback", "MAX " + "STATE_OTHER");
            }

        }

        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
            List<BluetoothGattService> services = gatt.getServices();
            Log.e("onServicesDiscovered", "MAX " + services.toString());

            /*
            for(int i = 0; i < services.size(); i++){
                for (int j = 0; j < services.get(i).getCharacteristics().size(); j++){
                    Log.e("MAX", "i= " + i + " j= " + j);
                    gatt.readCharacteristic(services.get(i).getCharacteristics().get
                            (j));
                }
            }
            */

            gatt.readCharacteristic(services.get(0).getCharacteristics().get(0));
        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt,
                                         BluetoothGattCharacteristic
                                                 characteristic, int status) {
            Log.e("onCharacteristicRead", "MAX " + characteristic.toString());
            Log.e("onCharacteristicRead", "MAX " +characteristic.getStringValue(0));
            //gatt.disconnect();
        }
    };
    }

编辑2：我的arduino代码

#include <SoftwareSerial.h>

/* Set up BT to arduino uno
BT RN4020    Arduino Uno
------------------------------------------------
Red          3.3V
Green        GND
Yellow(RX)   TX (digital pin 1)
Orange(TX)   RX (digital pin 0)
White        PIN 8 (!) This is not GND (!)
Blue         3.3V (Ioref can also be used)
*/

/* 
-----------------------------------------------------------------------------
-----EXPLANATION PROGRAM-----------------------------------------------------
----------------------------
Eerst wordt de BT module geïnitialiseerd door verschillende commando's door te
sturen. Bij elk commando wordt gecheckt of de BT module het juiste antwoord
heeft teruggestuurd.
De initialisatie moet gebeuren in CMD mode, de CMD/MLDP pin moet laag zijn. Na
de initialisatie checken we tot de BT module is geconnecteerd met het device.
Als de BT module geconnecteerd is zetten we deze uit CMD mode en in MLDP mode 
om het verzenden en ontvangen van data te ondersteunen. Daarna zenden we om de 
seconde de string 'test' door.
Dit gebeurt zolang het device geconnecteerd is met de BT module.
------------------------------------------------------------------------------
------------------------------------------------------------------------------
-----------------------------
*/

int CMD_MLD_pin = 8; // IO pin for CMD/MLDP pin (LOW --> CMD, HIGH --> MLDP)

void setup() // Initialising BT RN4020
{
  pinMode(CMD_MLD_pin, OUTPUT); 
  digitalWrite(CMD_MLD_pin, LOW); // put CMD/MLDP pin LOW for CMD mode
  delay(5000);
  /* Initialize Bluetooth */
  Serial.begin(115200); // Set up serial connection with required baud rate of 
                        // 115200
  delay(1500);
  Serial.println("R,1"); //Reboot
  while(!Serial.find("Reboot")){} // Waiting until BT RN4020 responds the 
  required string
  while(!Serial.find("CMD")){}
  //delay(2000);
  Serial.println("SF,1"); // Factory reset
  while(!Serial.find("AOK")){}
  //delay(1500);
  Serial.println("SR,32000000"); // Set device as peripheral
  while(!Serial.find("AOK")){}
  Serial.println("S-, Mobi"); // Change name of BT
  while(!Serial.find("AOK")){}
  //delay(1500);
  Serial.println("R,1"); // Reboot to make changes effective
  while(!Serial.find("Reboot")){}
  while(!Serial.find("CMD")){}
  //delay(2000);
}

void loop()
{
  // Wait until the device responds it is connected
  // If the device is connected we will send every second the string 'test'
  while(!Serial.find("Connected")){} // Wait until BT RN4020 is connected to a 
                                     // device
  digitalWrite(CMD_MLD_pin, HIGH); // Go to MLDP to support data stream
  while(!Serial.find("MLDP")){} // Wait until BT RN4020 is effectively in MLDP 
                                // mode
  delay(500);
  while (!Serial.find("Connection End")) // Send string to BTRN4020 while the 
                                         // BT RN4020 is conected to a device
  {
    Serial.println("test");
    delay(1000);
  }  
}

Answer 1

问了问题几个月后，我设法解决了我的问题。 那时我忘了分享我的解决方案。 无论如何，迟到总比没有好！

这是我在测试android-通过BLE的TI sensortag通信时编写的一些代码。

完整示例参见https://github.com/maxhelskens/SmergyBicycle

package com.example.max.smergy;

import android.annotation.TargetApi;
import android.app.Activity;
import android.app.ProgressDialog;
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.Bundle;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.util.SparseArray;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;
import java.util.UUID;

@TargetApi(21)
public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    private static final String DEVICE_NAME = "SensorTag";

    /* Humidity Service */
    private static final UUID HUMIDITY_SERVICE = UUID.fromString("F000AA20-0451-4000-B000-000000000000");
    private static final UUID HUMIDITY_DATA_CHAR = UUID.fromString("f000aa21-0451-4000-b000-000000000000");
    private static final UUID HUMIDITY_CONFIG_CHAR = UUID.fromString("f000aa22-0451-4000-b000-000000000000");
    /* magneto Service */
    private static final UUID MAGNETO_SERVICE = UUID.fromString("F000AA80-0451-4000-B000-000000000000");
    private static final UUID MAGNETO_DATA_CHAR = UUID.fromString("f000aa81-0451-4000-b000-000000000000");
    private static final UUID MAGNETO_CONFIG_CHAR = UUID.fromString("f000aa82-0451-4000-b000-000000000000");
    /* Barometric Pressure Service */
    private static final UUID PRESSURE_SERVICE = UUID.fromString("f000aa40-0451-4000-b000-000000000000");
    private static final UUID PRESSURE_DATA_CHAR = UUID.fromString("f000aa41-0451-4000-b000-000000000000");
    private static final UUID PRESSURE_CONFIG_CHAR = UUID.fromString("f000aa42-0451-4000-b000-000000000000");
    private static final UUID PRESSURE_CAL_CHAR = UUID.fromString("f000aa43-0451-4000-b000-000000000000");
    /* Client Configuration Descriptor */
    private static final UUID CONFIG_DESCRIPTOR = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb");


    private BluetoothAdapter mBluetoothAdapter;
    private SparseArray<BluetoothDevice> mDevices;

    private BluetoothGatt mGatt;

    private TextView mTemperature, mHumidity, mPressure;

    private ProgressDialog mProgress;

    private int REQUEST_ENABLE_BT = 1;
    private BluetoothLeScanner mLEScanner;
    private ScanSettings settings;
    private List<ScanFilter> filters;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setProgressBarIndeterminate(true);

        // Find the toolbar view inside the activity layout
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        // Sets the Toolbar to act as the ActionBar for this Activity window.
        // Make sure the toolbar exists in the activity and is not null
        setSupportActionBar(toolbar);


        /*
        * We are going to display the results in some text fields
        */
        mTemperature = (TextView) findViewById(R.id.text_temperature);
        mHumidity = (TextView) findViewById(R.id.text_humidity);
        mPressure = (TextView) findViewById(R.id.text_pressure);

        //Check if BLE is supported
        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();

        mDevices = new SparseArray<BluetoothDevice>();


        /*
        * A progress dialog will be needed while the connection process is
        * taking place
        */
        mProgress = new ProgressDialog(this);
        mProgress.setIndeterminate(true);
        mProgress.setCancelable(false);

    }

    @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<ScanFilter>();
            }
        }

        clearDisplayValues();
    }

    @Override
    protected void onPause() {
        super.onPause();

        //Make sure dialog is hidden
        mProgress.dismiss();
        //Cancel any scans in progress
        mHandler.removeCallbacks(mStopRunnable);
        mHandler.removeCallbacks(mStartRunnable);

        if (Build.VERSION.SDK_INT < 21) {
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        } else {
            mLEScanner.stopScan(mScanCallback);

        }
    }

    @Override
    protected void onStop() {
        super.onStop();
        //Disconnect from any active tag connection
        if (mGatt != null) {
            mGatt.close();
            mGatt = null;
        }
    }

    @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);
    }

    // Menu icons are inflated just as they were with actionbar
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);

        //Add any device elements we've discovered to the overflow menu
        for (int i=0; i < mDevices.size(); i++) {
            BluetoothDevice device = mDevices.valueAt(i);
            menu.add(0, mDevices.keyAt(i), 0, device.getName());
        }

        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.bluetoothSearch:
                mDevices.clear();
                startScan();
                //scanLeDevice(true);

                return true;
            default:
                //Obtain the discovered device to connect with
                BluetoothDevice device = mDevices.get(item.getItemId());
                Log.i(TAG, "Connecting to " + device.getName());
                /*
                * Make a connection with the device
                */

                connectToDevice(device);
                //Display progress UI
                mHandler.sendMessage(Message.obtain(null, MSG_PROGRESS, "Connecting to " + device.getName() + "..."));
                return super.onOptionsItemSelected(item);
        }
    }

    private void clearDisplayValues() {
        mTemperature.setText("---");
        mHumidity.setText("---");
        mPressure.setText("---");
    }

    private Runnable mStopRunnable = new Runnable() {
        @Override
        public void run() {
            stopScan();
        }
    };
    private Runnable mStartRunnable = new Runnable() {
        @Override
        public void run() {
            startScan();
        }
    };

    private void startScan() {
        if (Build.VERSION.SDK_INT < 21) {
            mBluetoothAdapter.startLeScan(mLeScanCallback);
        } else {
            mLEScanner.startScan(filters, settings, mScanCallback);
        }
        setProgressBarIndeterminateVisibility(true);

        mHandler.postDelayed(mStopRunnable, 2500);
    }

    private void stopScan() {
        if (Build.VERSION.SDK_INT < 21) {
            mBluetoothAdapter.stopLeScan(mLeScanCallback);
        } else {
            mLEScanner.stopScan(mScanCallback);

        }
        setProgressBarIndeterminateVisibility(false);
    }

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

                    mDevices.put(device.hashCode(), device);
                    //Update the overflow menu
                    invalidateOptionsMenu();
                }
            };

/*

    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();

            mDevices.put(btDevice.hashCode(), btDevice);
            //Update the overflow menu
            invalidateOptionsMenu();
        }

        @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);
        }
    };


    public void connectToDevice(BluetoothDevice device) {
        if (mGatt == null) {
            mGatt = device.connectGatt(this, false, gattCallback);
            stopScan();
        }
    }


    /*
    * In this callback, we've created a bit of a state machine to enforce that only
    * one characteristic be read or written at a time until all of our sensors
    * are enabled and we are registered to get notifications.
    */
    private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {
        /* State Machine Tracking */
        private int mState = 0;

        private void reset() { mState = 0; }

        private void advance() { mState++; }

        /*
        * Send an enable command to each sensor by writing a configuration
        * characteristic.  This is specific to the SensorTag to keep power
        * low by disabling sensors you aren't using.
        */
        private void enableNextSensor(BluetoothGatt gatt) {
            BluetoothGattCharacteristic characteristic;
            switch (mState) {
                /*
                case 0:
                    Log.d(TAG, "Enabling pressure cal");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_CONFIG_CHAR);
                    characteristic.setValue(new byte[] {0x02});
                    break;
                case 1:
                    Log.d(TAG, "Enabling pressure");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_CONFIG_CHAR);
                    characteristic.setValue(new byte[] {0x01});
                    break;  */
                case 0:
                    Log.d(TAG, "Enabling humidity");
                    characteristic = gatt.getService(HUMIDITY_SERVICE)
                            .getCharacteristic(HUMIDITY_CONFIG_CHAR);
                    characteristic.setValue(new byte[] {0x01});
                    break;
                case 1:
                    Log.d(TAG, "Enabling magneto");
                    characteristic = gatt.getService(MAGNETO_SERVICE)
                            .getCharacteristic(MAGNETO_CONFIG_CHAR);
                    characteristic.setValue(new byte[] {(byte)0x7F, (byte)0x00});
                    break;
                default:
                    mHandler.sendEmptyMessage(MSG_DISMISS);
                    Log.i(TAG, "All Sensors Enabled");
                    return;
            }

            gatt.writeCharacteristic(characteristic);
        }

        /*
        * Read the data characteristic's value for each sensor explicitly
        */
        private void readNextSensor(BluetoothGatt gatt) {
            BluetoothGattCharacteristic characteristic;
            switch (mState) {
                /*
                case 0:
                    Log.d(TAG, "Reading pressure cal");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_CAL_CHAR);
                    break;
                case 1:
                    Log.d(TAG, "Reading pressure");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_DATA_CHAR);
                    break;*/
                case 0:
                    Log.d(TAG, "Reading humidity");
                    characteristic = gatt.getService(HUMIDITY_SERVICE)
                            .getCharacteristic(HUMIDITY_DATA_CHAR);
                    break;
                case 1:
                    Log.d(TAG, "Reading magneto");
                    characteristic = gatt.getService(MAGNETO_SERVICE)
                            .getCharacteristic(MAGNETO_DATA_CHAR);
                    break;
                default:
                    mHandler.sendEmptyMessage(MSG_DISMISS);
                    Log.i(TAG, "All Sensors Enabled");
                    return;
            }

            gatt.readCharacteristic(characteristic);
        }


        /*
        * Enable notification of changes on the data characteristic for each sensor
        * by writing the ENABLE_NOTIFICATION_VALUE flag to that characteristic's
        * configuration descriptor.
        */
        private void setNotifyNextSensor(BluetoothGatt gatt) {
            BluetoothGattCharacteristic characteristic;
            switch (mState) {
                /*
                case 0:
                    Log.d(TAG, "Set notify pressure cal");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_CAL_CHAR);
                    break;
                case 1:
                    Log.d(TAG, "Set notify pressure");
                    characteristic = gatt.getService(PRESSURE_SERVICE)
                            .getCharacteristic(PRESSURE_DATA_CHAR);
                    break;*/
                case 0:
                    Log.d(TAG, "Set notify humidity");
                    characteristic = gatt.getService(HUMIDITY_SERVICE)
                            .getCharacteristic(HUMIDITY_DATA_CHAR);
                    break;
                case 1:
                    Log.d(TAG, "Set notify magneto");
                    characteristic = gatt.getService(MAGNETO_SERVICE)
                            .getCharacteristic(MAGNETO_DATA_CHAR);
                    break;
                default:
                    mHandler.sendEmptyMessage(MSG_DISMISS);
                    Log.i(TAG, "All Sensors Enabled");
                    return;
            }

            //Enable local notifications
            gatt.setCharacteristicNotification(characteristic, true);
            //Enabled remote notifications
            BluetoothGattDescriptor desc = characteristic.getDescriptor(CONFIG_DESCRIPTOR);
            desc.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
            gatt.writeDescriptor(desc);
        }


        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            Log.i("onConnectionStateChange", "Status: " + status);
            if (status == BluetoothGatt.GATT_SUCCESS && newState == BluetoothProfile.STATE_CONNECTED) {
                /*
                * Once successfully connected, we must next discover all the services on the
                * device before we can read and write their characteristics.
                */
                gatt.discoverServices();
                mHandler.sendMessage(Message.obtain(null, MSG_PROGRESS, "Discovering Services..."));
            } else if (status == BluetoothGatt.GATT_SUCCESS && newState == BluetoothProfile.STATE_DISCONNECTED) {
                /*
                * If at any point we disconnect, send a message to clear the weather values
                * out of the UI
                */
                mHandler.sendEmptyMessage(MSG_CLEAR);
            } else if (status != BluetoothGatt.GATT_SUCCESS) {
                /*
                * If there is a failure at any stage, simply disconnect
                */
                gatt.close();
            }

        }

        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
            List<BluetoothGattService> services = gatt.getServices();
            Log.i("onServicesDiscovered", services.toString());

            mHandler.sendMessage(Message.obtain(null, MSG_PROGRESS, "Enabling Sensors..."));
            /*
            * With services discovered, we are going to reset our state machine and start
            * working through the sensors we need to enable
            */
            reset();
            enableNextSensor(gatt);
        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
            Log.i("onCharacteristicRead", characteristic.toString());
            //For each read, pass the data up to the UI thread to update the display
            if (HUMIDITY_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_HUMIDITY, characteristic));
            }
            if (MAGNETO_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_MAGNETO, characteristic));
            }
            if (PRESSURE_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_PRESSURE, characteristic));
            }
            if (PRESSURE_CAL_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_PRESSURE_CAL, characteristic));
            }

            //After reading the initial value, next we enable notifications
            setNotifyNextSensor(gatt);
        }

        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
            //After writing the enable flag, next we read the initial value
            readNextSensor(gatt);
        }

        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
            /*
            * After notifications are enabled, all updates from the device on characteristic
            * value changes will be posted here.  Similar to read, we hand these up to the
            * UI thread to update the display.
            */
            if (HUMIDITY_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_HUMIDITY, characteristic));
            }
            if (MAGNETO_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_MAGNETO, characteristic));
            }
            if (PRESSURE_DATA_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_PRESSURE, characteristic));
            }
            if (PRESSURE_CAL_CHAR.equals(characteristic.getUuid())) {
                mHandler.sendMessage(Message.obtain(null, MSG_PRESSURE_CAL, characteristic));
            }
        }

        @Override
        public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
            //Once notifications are enabled, we move to the next sensor and start over with enable
            advance();
            enableNextSensor(gatt);
        }

        @Override
        public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) {
            Log.d(TAG, "Remote RSSI: " + rssi);
        }

        private String connectionState(int status) {
            switch (status) {
                case BluetoothProfile.STATE_CONNECTED:
                    return "Connected";
                case BluetoothProfile.STATE_DISCONNECTED:
                    return "Disconnected";
                case BluetoothProfile.STATE_CONNECTING:
                    return "Connecting";
                case BluetoothProfile.STATE_DISCONNECTING:
                    return "Disconnecting";
                default:
                    return String.valueOf(status);
            }
        }
    };


    /*
    * We have a Handler to process event results on the main thread
    */
    private static final int MSG_HUMIDITY = 101;
    private static final int MSG_PRESSURE = 102;
    private static final int MSG_PRESSURE_CAL = 103;
    private static final int MSG_MAGNETO = 104;
    private static final int MSG_PROGRESS = 201;
    private static final int MSG_DISMISS = 202;
    private static final int MSG_CLEAR = 301;
    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            BluetoothGattCharacteristic characteristic;
            switch (msg.what) {
                case MSG_HUMIDITY:
                    characteristic = (BluetoothGattCharacteristic) msg.obj;
                    if (characteristic.getValue() == null) {
                        Log.w(TAG, "Error obtaining humidity value");
                        return;
                    }
                    updateHumidityValues(characteristic);
                    break;
                case MSG_MAGNETO:
                    characteristic = (BluetoothGattCharacteristic) msg.obj;
                    if (characteristic.getValue() == null) {
                        Log.w(TAG, "Error obtaining magneto value");
                        return;
                    }
                    updateMagnetoValues(characteristic);
                    break;
                case MSG_PRESSURE:
                    characteristic = (BluetoothGattCharacteristic) msg.obj;
                    if (characteristic.getValue() == null) {
                        Log.w(TAG, "Error obtaining pressure value");
                        return;
                    }
                    updatePressureValue(characteristic);
                    break;
                case MSG_PRESSURE_CAL:
                    characteristic = (BluetoothGattCharacteristic) msg.obj;
                    if (characteristic.getValue() == null) {
                        Log.w(TAG, "Error obtaining cal value");
                        return;
                    }
                    updatePressureCals(characteristic);
                    break;
                case MSG_PROGRESS:
                    mProgress.setMessage((String) msg.obj);
                    if (!mProgress.isShowing()) {
                        mProgress.show();
                    }
                    break;
                case MSG_DISMISS:
                    mProgress.hide();
                    break;
                case MSG_CLEAR:
                    clearDisplayValues();
                    break;
            }
        }
    };

    /* Methods to extract sensor data and update the UI */

    private void updateHumidityValues(BluetoothGattCharacteristic characteristic) {
        double humidity = SensorTagData.extractHumidity(characteristic);

        mHumidity.setText(String.format("%.0f%%", humidity));
    }

    ArrayList<Double> magnets = new ArrayList<>();
    double average = 0;
    int count = -1;
    int wait5 = 0;

    private void updateMagnetoValues(BluetoothGattCharacteristic characteristic) {
        double magnet = SensorTagData.extractMagnetoX(characteristic);
        Log.e("MAGNETO", "" + magnet);
        magnet = Math.abs(magnet);

        if (wait5 == 0) {

            if (magnet > average + 300 ||  magnet < average - 300) {
                wait5 = 6;

                count ++;
                mPressure.setText("" + count);
            }
        }
        else {
            wait5 --;
        }

        if (magnets.size() >= 5) {
            magnets.remove(0);
        }
        magnets.add(magnet);
        double sum = 0;
        for (int i = 0; i < magnets.size(); i++) {
            sum += magnets.get(i);
        }
        average = sum/magnets.size();
        average = magnets.get(2);

        //mHumidity.setText(String.format("%.0f%%", humidity));

    }

    private int[] mPressureCals;
    private void updatePressureCals(BluetoothGattCharacteristic characteristic) {
        mPressureCals = SensorTagData.extractCalibrationCoefficients(characteristic);
    }

    private void updatePressureValue(BluetoothGattCharacteristic characteristic) {
        if (mPressureCals == null) return;
        double pressure = SensorTagData.extractBarometer(characteristic, mPressureCals);
        double temp = SensorTagData.extractBarTemperature(characteristic, mPressureCals);

        mTemperature.setText(String.format("%.1f\u00B0C", temp));
        mPressure.setText(String.format("%.2f", pressure));
    }
}

Answer 2

好吧，我认为您应该对如何使用这些特性做更多的阅读。 默认情况下，您的芯片具有许多特性，其中大部分包含来自芯片的信息。 为了发送和接收数据，您必须先对芯片进行编程，以通过特定特性发送数据并通过另一个特定特性接收数据。

某些芯片具有默认的Rx和Tx特性，应使用这些特性来发送和接收数据。 这些特性充当BLE与芯片上的Tx和Rx引脚之间的流水线，并将简单地回显所有数据。

或者，您可以在BLE服务上创建自己的特征，并编写自己的发送和接收协议。

让我举一个简单的例子：

假设您正在使用芯片的默认特性来发送数据。 必须以小块（例如20个字节）发送此数据。 要在Android上读取此数据，您必须首先获取该特征的描述符并启用通知。 这将告诉Android聆听该特性并监视更改。

    characteristic = gatt.getService(UUID.fromString(SERVICE_UUID)).getCharacteristic(UUID.fromString(CHARACTERISTIC_UUID)); //Find you characteristic
    mGatt.setCharacteristicNotification(characteristic, true); //Tell you gatt client that you want to listen to that characteristic
    List<BluetoothGattDescriptor> descriptors = characteristic.getDescriptors(); //find the descriptors on the characteristic
    BluetoothGattDescriptor descriptor = descriptors.get(1); //get the right descriptor for setting notifications
    descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);
    mGatt.writeDescriptor(descriptor); //apply these changes to the ble chip to tell it we are ready for the data

完成此操作后，您将能够使用onCharacteristicChanged方法读取数据：

@Override
public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
    super.onCharacteristicChanged(gatt, characteristic);
    String data = characteristic.getStringValue(0);
}

发送数据会更简单。 找到特征后，只需将数据分块写入该特征：

byte[] value = new byte[1];
value[0] = (byte) (21 & 0xFF); //your data
characteristic.setValue(value); //assign the new data value to the characteristic
boolean success = mBluetoothGatt.writeCharacteristic(charac); //write to the chip

写入后，芯片将刷新特性并将数据发送到芯片的Tx引脚。

编辑：

浏览RN4020的用户手册 ，您会看到该芯片具有默认的电池服务以及型号，软件版本等的某些特性，但没有默认的Rx和Tx特性。

在这种情况下，您在代码中发现的特征只是设备信息，几乎没有用。 您必须首先在芯片上定义自己的专用服务和特性。 请参见手册中的示例3-1。 使用唯一的UUID定义私有服务和特征后，您可以将其写入数据，并使用相同的UUID在Android上读取数据。

Answer 3

我在arduino平台上结合了Processing.org中的RN4020。 如果您仍然很感兴趣，请告诉我。

您是否将SW-wake和HW唤醒引脚连接到vcc 3.3v？ 您不必在开始时就参加CMD。

我只是将CDM直接连接到VCC。 输入重新启动命令后，它将直接进入MLDP。