android低功耗蓝牙APP开发问题记录

概述：实现了BLE扫描、连接、读写、通知接收等操作。
1、扫描方法的回调函数更改
在android5.0（SDK 21）以上时，BluetoothAdapter.startLeScan（）和stopLEScan已经过时，所以在5.0以上时需要判定android版本.
扫描代码：

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);            }        }    }

回调函数：

 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 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);                        }                    });                }            };

2、Android6.0权限问题
在手机上编译调试时，由于android6.0系统APP权限改为手动添加，则在调试低版本android BLE程序时要在build.gradle中将targetSdkVersion改为23以下，否则会运行出错。要想完全解决该问题，则需要判断android系统版本，查看android6.0的权限文档对代码进行修改。
例如：

3、低功耗蓝牙读写通信

package com.example.lenovo.ss1003;import android.app.Service;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.Intent;import android.os.Binder;import android.os.Handler;import android.os.IBinder;import android.util.Log;import android.widget.Toast;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.UUID;import static android.bluetooth.BluetoothAdapter.STATE_DISCONNECTED;/** * Created by lenovo on 2016/11/8. */public class BluetoothLeService extends Service {    //预定义    private Handler mHandler;    private final String LIST_NAME = "NAME";    private final String LIST_UUID = "UUID";    private final static String TAG = BluetoothLeService.class.getSimpleName();    private ArrayList> mGattCharateristics = new ArrayList>();//蓝牙数据描述对象链表    private BluetoothManager bluetoothManager;    private BluetoothAdapter bluetoothAdapter;    private String mBluetoothDeviceAddress;    private BluetoothGatt bluetoothGatt;    public BluetoothGattService mBluetoothGattService;    private BluetoothGattCharacteristic mBluetoothGattCharacteristic;    private int mConnectionState = STATE_CONNECTED;    private static final int STATE_CONNECTING = 1;    private static final int STATE_CONNECTED = 2;    static final String ACTION_GATT_CONNECTED = "com.example.bluetooth.le.ACTION_GATT_CONNECTED";    static final String ACTION_GATT_DISCONNECTED = "com.example.bluetooth.le.ACTION_GATT_DISCONNECTED";    private static final String ACTION_GATT_SERVICES_DISCONNECTED = "com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCONNECTED";    public final static String ACTION_GATT_SERVICES_DISCOVERED = "com.example.bluetooth.le.ACTION_GATT_SERVICES_DISCOVERED";    public final static String ACTION_GATT_WRITE="com.example.bluetooth.le.ACTION_WRITE";    static final String ACTION_DATA_AVAILABLE = "com.example.bluetooth.le.ACTION_DATA_AVAILABLE";    static final String EXTRA_DATA = "com.example.bluetooth.le.EXTRA_DATA";    public final static UUID UUID_TENS_MEASUREMWNT = UUID.fromString(SampleGattAttributes.TENS_MEASUREMENT);    public final static UUID UUID_TENS_CHARACTERISTIC = UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_CONFIG);    private final BluetoothGattCallback mGattCallback = new BluetoothGattCallback() {        //获取蓝牙的连接状态，gatt客户端，status蓝牙连接操作成功后的连接状态，newState返回新的连接状态        @Override        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {            String intentAction;            //判断蓝牙新的连接状态，更新并发送广播            if (newState == BluetoothProfile.STATE_CONNECTED) {                intentAction = ACTION_GATT_CONNECTED;                mConnectionState = STATE_CONNECTED;                broadcastUpdate(intentAction);                Log.i(TAG, "Connected to GATT server");                Log.i(TAG, "Attempting to start service discovery" + bluetoothGatt.discoverServices());            } else if (newState == BluetoothProfile.STATE_DISCONNECTED) {                intentAction = ACTION_GATT_DISCONNECTED;                mConnectionState = STATE_DISCONNECTED;                Log.i(TAG, "Disconnected from GATT server");                broadcastUpdate(intentAction);            }        }        //readCharacteristic的时候会触发        @Override        public void onCharacteristicRead(BluetoothGatt gatt,                                         BluetoothGattCharacteristic characteristic,                                         int status) {            if (status == BluetoothGatt.GATT_SUCCESS) {                broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);                Log.e("---------------", "onCharacteristicRead可用");            }        }        //回调显示一个远程变化，broadcastUpdate更新变化数据；        @Override        public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {            broadcastUpdate(ACTION_DATA_AVAILABLE, characteristic);            Log.e("---------------", "onCharacteristicChanged可用");        }        @Override        public void onCharacteristicWrite(BluetoothGatt mBluetoothGatt,                                          BluetoothGattCharacteristic characteristic, int status) {            super.onCharacteristicWrite(mBluetoothGatt, characteristic, status);            Log.e(TAG, "onCharWrite " + mBluetoothGatt.getDevice().getName()                    + " write "                    + characteristic.getUuid().toString()                    + " -> ");        }        @Override        public void onDescriptorRead(BluetoothGatt gatt,                                     BluetoothGattDescriptor descriptor, int status) {            Log.w("lwj", "lwj---onDescriptorRead");            // TODO Auto-generated method stub            //super.onDescriptorRead(gatt, descriptor, status);        }        @Override        public void onDescriptorWrite(BluetoothGatt gatt,                                      BluetoothGattDescriptor descriptor, int status) {            UUID uuid = descriptor.getCharacteristic().getUuid();        }        @Override        public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) {            Log.w("lwj", "lwj---onReadRemoteRssi");            // TODO Auto-generated method stub            super.onReadRemoteRssi(gatt, rssi, status);        }        @Override        public void onReliableWriteCompleted(BluetoothGatt gatt, int status) {            Log.w("lwj", "lwj---onReliableWriteCompleted");            // TODO Auto-generated method stub            super.onReliableWriteCompleted(gatt, status);        }// 蓝牙连接后回调该函数，立即执行 onServicesDiscovered方法，下列Log都会在Android studio 的error中打印        @Override        public void onServicesDiscovered(BluetoothGatt gatt, int status) {            // TODO Auto-generated method stub            super.onServicesDiscovered(gatt, status);            //discoverServices()函数的回调函数            if (status == BluetoothGatt.GATT_SUCCESS) {                Log.e(TAG, "discoverServices完成");                mBluetoothGattService = gatt.getService(UUID_TENS_MEASUREMWNT);                //还需要进行判断是否为null                if (mBluetoothGattService == null) {                    Log.e(TAG, "getService未成功");                } else {                    Log.e(TAG, "getService成功");                }                //再通过mBluetoothGattService获得BluetoothGattCharacteri                mBluetoothGattCharacteristic =                        mBluetoothGattService.getCharacteristic(UUID_TENS_CHARACTERISTIC);                //还需要在进行判断是否为null                if (mBluetoothGattCharacteristic == null) {                    Log.e(TAG, "getCharacteristic未成功");                } else {                     Log.e(TAG, "getCharacteristic成功");                }            }else {                Log.e(TAG, "discoverServices未完成");//              Toast.makeText(MainActivity.this, "discover不成功，请再尝试", Toast.LENGTH_LONG).show();            }         **Log.e("++++++++++++",displayGattServices(getSupportedGattServices()).get(3).get(7).toString());         //行为广播，可在已绑定的Acivity中获取；            broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);        }**    };    //广播发送，更新意图对象。    private void broadcastUpdate(String action) {        final Intent intent=new Intent(action);        sendBroadcast(intent);    }    //更新蓝牙行为数据和远程设备    private void broadcastUpdate(final String action, final BluetoothGattCharacteristic characteristic) {        //创建意图对象        final Intent intent = new Intent(action);        //如果TENS_MEASUREMWNT的UUID和获取设备UUID匹配；        if (UUID_TENS_MEASUREMWNT.equals(characteristic.getUuid())) {            int flag = characteristic.getProperties();//获取设备属性            int format = -1;            if ((flag & 0x01) != 0) {                format = BluetoothGattCharacteristic.FORMAT_UINT16;//将uuid转为16进制格式                Log.d(TAG, "Heart rate format UINT16");            } else {                format = BluetoothGattCharacteristic.FORMAT_UINT8;//将uuid转为8进制格式                Log.d(TAG, "Heart rate format UINT8");            }            //            final int TENS = characteristic.getIntValue(format, 1);            Log.d(TAG, String.format("Recevied TENS data:%d", TENS));            intent.putExtra(EXTRA_DATA, String.valueOf(TENS));//将心率的数据添加到intent对象中；        } else {            //如果数据是byte形式数据，将遍历数据并转化为String形式添加到intent中；            final byte[] data = characteristic.getValue();            if (data != null && data.length > 0) {                final StringBuilder stringBuilder = new StringBuilder(data.length);                for (byte byteChar : data) {                    stringBuilder.append(String.format("%02X", byteChar));                    intent.putExtra(EXTRA_DATA, new String(data) + "\n" + stringBuilder.toString());                }            }            sendBroadcast(intent);//广播转发intent对象；        }    }//继承Binder类实现BluetoothLeService 的getService方法；    public class LocalBinder extends Binder {        BluetoothLeService getService() {            return BluetoothLeService.this;        }    }    private final IBinder mBinder = new LocalBinder();    //绑定intent对象，作为intent和service之间的数据传递中间者。    @Override    public IBinder onBind(Intent intent) {        return mBinder;    }    //解除绑定    @Override    public boolean onUnbind(Intent intent) {        close();        return super.onUnbind(intent);    }    public boolean initialize() {        if (bluetoothManager == null) {            bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);//通过蓝牙管理者获取当前系统蓝牙服务            if (bluetoothManager == null) {                return false;            }        }        bluetoothAdapter = bluetoothManager.getAdapter();//获取适配器        if (bluetoothAdapter == null) {            return false;        }        return true;    }    /*          * 获取低功耗蓝牙设备后，连接到GATT服务          * 目的设备的地址作为参数；          * 连接初始化成功后异步连接到设备；          * */    //判断蓝牙是否可连接    public boolean Connect(final String address) {        if (bluetoothAdapter == null || address == null) {            Log.w(TAG, "BluetoothAdapter not initialized or unspecified address.");            return false;        }else if (mBluetoothDeviceAddress != null && address.equals(mBluetoothDeviceAddress)                && bluetoothGatt != null) {            Log.d(TAG, "Trying to use an existing mBluetoothGatt for connection.");            if (bluetoothGatt.connect()) {                mConnectionState = STATE_CONNECTING;                return true;            } else {                return false;            }        }        final BluetoothDevice device = bluetoothAdapter.getRemoteDevice(address);        if (device == null) {            Log.w(TAG, "Device not found.  Unable to connect.");            return false;        }        // We want to directly connect to the device, so we are setting the autoConnect        // parameter to false.        bluetoothGatt = device.connectGatt(this,true, mGattCallback);//true是设置自动连接蓝牙；        Log.e(TAG, "Trying to create a new connection.");        if(bluetoothGatt.connect()){           // Toast.makeText(this, "连接成功",Toast.LENGTH_LONG).show();            //连接成功后，再进行discoverServices()            //并在其回调函数中执行getService(),获得BluetoothGattService            if(bluetoothGatt.discoverServices()){                Log.e(TAG, "discoverServices已经开始了");            }else{                Log.e(TAG, "discoverServices没有开始");            }        }        else{            Toast.makeText(this, "未连接成功,请再尝试", Toast.LENGTH_LONG).show();        }        mBluetoothDeviceAddress = address;        mConnectionState = STATE_CONNECTING;        return true;    }    public void DisConnect(){        if(bluetoothAdapter==null||bluetoothGatt==null){            return;        }        bluetoothGatt.disconnect();    }    //关闭服务，释放Service绑定对象    private void close() {        if(bluetoothGatt==null){            return;        }        bluetoothGatt.close();        bluetoothGatt=null;    }   //读取蓝牙设备特征，如果蓝牙适配器为空则返回空对象；否则读取蓝牙特征值    public void readCharacteristic(BluetoothGattCharacteristic characterristic){        if(bluetoothAdapter==null||bluetoothGatt==null){            Log.e("=============", "适配器或协议栈为空");        }else {            bluetoothGatt.readCharacteristic(characterristic);            Log.e("=============", "开始读取");        }    }    //写入指定的characteristic    public void writeCharacteristic(BluetoothGattCharacteristic characteristic) {        if (bluetoothAdapter == null || bluetoothGatt == null) {            Log.w(TAG, "BluetoothAdapter not initialized");            return;        }        bluetoothGatt.writeCharacteristic(characteristic);    }    //获取蓝牙支持的服务    public List getSupportedGattServices(){        if(bluetoothGatt==null) {            return null;        }else            return bluetoothGatt.getServices();    }    /*      设置蓝牙通信是否可获取通知；      如果bluetoothAdapter和bluetoothGatt都不为null，可向bluetoothGatt中设置蓝牙可通知；      其中public static String CLIENT_CHARACTERISTIC_READ="00002902-0000-1000-8000-00805f9b34fb"，是notify中的descriptor的UUID，必须对其进行descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE)设置，否知收不到通知。向设备写数据时需要延时操作（200m以上）才能在广播接收者内接收到notify。    */   public void setCharacteristicNotification(BluetoothGattCharacteristic characteristic,boolean enabled) {        if (bluetoothAdapter == null || bluetoothGatt == null) {            Log.e(TAG, "BluetoothAdapter not initalized");            return;        }else {                BluetoothGattDescriptor descriptor = characteristic.getDescriptor(UUID.fromString(SampleGattAttributes.CLIENT_CHARACTERISTIC_READ));                descriptor.setValue(BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE);                bluetoothGatt.writeDescriptor(descriptor);                Log.e("设置descriptor：",descriptor.toString());            bluetoothGatt.setCharacteristicNotification(characteristic, enabled);            Log.e("设置notify：",characteristic.getUuid().toString()+enabled);        }    }    //遍历蓝牙service和Characteristic列表，返回二维数组；  public ArrayList> displayGattServices(List gattServices) {      if (gattServices == null){ return null;}      String uuid = null;      String unknownServiceString = getResources().getString(R.string.unknown_service);      String unknownCharaString = getResources().getString(R.string.unknown_characteristic);      ArrayList> gattServiceData = new ArrayList>();      ArrayList>> gattCharacteristicData              = new ArrayList>>();      mGattCharateristics= new ArrayList>();      // Loops through available GATT Services.      for (BluetoothGattService gattService : gattServices) {          HashMap currentServiceData = new HashMap();          uuid = gattService.getUuid().toString();          currentServiceData.put(                  LIST_NAME, SampleGattAttributes.lookup(uuid, unknownServiceString));          currentServiceData.put(LIST_UUID, uuid);          gattServiceData.add(currentServiceData);          ArrayList> gattCharacteristicGroupData =                  new ArrayList>();          List gattCharacteristics =                  gattService.getCharacteristics();          ArrayList charas =                  new ArrayList();          // Loops through available Characteristics.          for (final BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) {              charas.add(gattCharacteristic);              HashMap currentCharaData = new HashMap();              uuid = gattCharacteristic.getUuid().toString();              currentCharaData.put(                      LIST_NAME, SampleGattAttributes.lookup(uuid, unknownCharaString));              currentCharaData.put(LIST_UUID, uuid);              gattCharacteristicGroupData.add(currentCharaData);                  //接受Characteristic被写的通知,收到蓝牙模块的数据后会触发mOnDataAvailable.onCharacteristicWrite()              setCharacteristicNotification(gattCharacteristic, true);          }          mGattCharateristics.add(charas);          gattCharacteristicData.add(gattCharacteristicGroupData);      }/*      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(0).getUuid()));      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(1).getUuid()));      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(2).getUuid()));      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(3).getUuid()));      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(4).getUuid()));      Log.e("---------", String.valueOf(mGattCharateristics.get(3).get(5).getUuid()));*/      return  mGattCharateristics;  } }

 private BluetoothGattCharacteristic mGattCharateristics;//蓝牙数据描述对象链表    private BluetoothGatt mBluetoothGatt;    private BluetoothLeService mBluetoothLeService;    public static final String EXTRAS_DEVICE_ADDRESS = "DEVICE_ADDRESS";//外部仪器地址    private String mDeviceAddress;    BluetoothGattCharacteristic mCharacteristic;    private ArrayList> mGattCharacteristics =            new ArrayList>();             private final ServiceConnection mServiceConnection = new ServiceConnection() {     **//初始化蓝牙连接服务，如果蓝牙初始化成功则进行蓝牙连接；如果没有此方法，广播接收者无法接收数据，则不能进行读写操作。**       @Override        public void onServiceConnected(ComponentName componentName, IBinder iBinder) {            mBluetoothLeService = ((BluetoothLeService.LocalBinder) iBinder).getService();            if (!mBluetoothLeService.initialize()) {//判断蓝牙是否初始化                finish();            }            mBluetoothLeService.Connect(mDeviceAddress);        }        @Override        public void onServiceDisconnected(ComponentName componentName) {            mBluetoothLeService = null;        }    };    private final BroadcastReceiver mGattUpdateReceiver = new BroadcastReceiver() {        @Override        public void onReceive(Context context, Intent intent) {            final String action = intent.getAction();            if (BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED.equals(action)) {                mGattCharacteristics=mBluetoothLeService.displayGattServices(mBluetoothLeService.getSupportedGattServices());            }else if (BluetoothLeService.ACTION_DATA_AVAILABLE.equals(action)) {                intent.getStringExtra(BluetoothLeService.EXTRA_DATA);                Log.e("+++++++++++",intent.getStringExtra(BluetoothLeService.EXTRA_DATA).toString());            }        }    };  protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_treatment);        final Intent intent = getIntent();        mDeviceAddress = intent.getStringExtra(EXTRAS_DEVICE_ADDRESS);        Intent gattServiceIntent = new Intent(this, BluetoothLeService.class);        bindService(gattServiceIntent, mServiceConnection, BIND_AUTO_CREATE);        }@Override    protected void onResume() {        super.onResume();        //发送数据，应该在按钮监听中添加，这里没有设置按钮，就添加在此方法中。   mGattCharateristics = mGattCharacteristics.get(3).get(8);                Log.e("======",mGattCharateristics.getUuid().toString());                final int charaProp =mGattCharateristics.getProperties();                byte data[] = {(byte)0x33, (byte)0x03, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00, (byte)0x00};                //final int charaProp =CharacteristicService.getProperties();                if ((charaProp|BluetoothGattCharacteristic.PROPERTY_WRITE) > 0) {                    if (mGattCharateristics != null) {                        Log.d("NotifyCharacteristic:", mGattCharateristics.toString());                        mBluetoothLeService.setCharacteristicNotification(                                mGattCharateristics, true);                    }                    mGattCharateristics.setValue(data);//随便举个数据                    mBluetoothLeService.writeCharacteristic(mGattCharateristics);//写命令到设备，                    Log.e("++++++","数据发送成功");                }    }    @Override    protected void onPause() {        super.onPause();        unregisterReceiver(mGattUpdateReceiver);    }    @Override    protected void onDestroy() {        super.onDestroy();    }    private IntentFilter makeGattUpdateIntentFilter() {        final IntentFilter intentFilter = new IntentFilter();        intentFilter.addAction(BluetoothLeService.ACTION_GATT_CONNECTED);        intentFilter.addAction(BluetoothLeService.ACTION_GATT_DISCONNECTED);        intentFilter.addAction(BluetoothLeService.ACTION_GATT_SERVICES_DISCOVERED);        intentFilter.addAction(BluetoothLeService.ACTION_DATA_AVAILABLE);        return intentFilter;    }

4、android全局变量设置
目的：用于获取的蓝牙BluetoothGattCharacteristic在activity之间传递，否则一个activity销毁后，另一个activity无法获取。
(1)、在AndroidManifest文件中配置全局变量。

<application        android:allowBackup="true"        android:name=".BluetoothGattBean"        android:icon="@mipmap/ic_launcher"        android:label="@string/app_name"        android:supportsRtl="true"        android:theme="@style/AppTheme">        <activity android:name=".MainActivity">            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            intent-filter>        activity>    application>

(2)、创建全局变量类

import android.app.Application;import android.bluetooth.BluetoothGattCharacteristic;import java.util.ArrayList;/** * Created by lenovo on 2016/12/20. */public class BluetoothGattBean extends Application {    private ArrayList> bluetoothGattCharacteristicList;    public void setBluetoothGattCharacteristicList(ArrayList> bluetoothGattCharacteristicList) {        this.bluetoothGattCharacteristicList = bluetoothGattCharacteristicList;    }    public ArrayList> getBluetoothGattCharacteristicList() {        return bluetoothGattCharacteristicList;    }}

(3)、向全局变量中保存广播接收者获取的数据

btn.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) { final BluetoothGattBean bluetoothGattBean= (BluetoothGattBean)getApplication();              bluetoothGattBean.setBluetoothGattCharacteristicList(mGattCharacteristics);                Intent bleIntent = new Intent(DeviceControlActivity.this,                        BleCommunicationActivity.class);                  }                        }）；

(4)、获取上一个activity保存的全局变量数据用于读写操作。

 btn.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) {                value=0;                intensity_value.setText("0");                final BluetoothGattBean bluetoothGattBean= (BluetoothGattBean)getApplication();                mGattCharacteristics=bluetoothGattBean.getBluetoothGattCharacteristicList();                mCharacteristic = mGattCharacteristics.get(3).get(8);                Log.e（"获取的BluetoothGattCharacteristic为：",mCharacteristic）        });

5、倒计时

package utils;import android.content.Context;import android.util.AttributeSet;import android.widget.TextView;public class TimerTextView extends TextView implements Runnable {    public static String Ltime = null;    public TimerTextView(Context context, AttributeSet attrs) {        super(context, attrs);        // TODO Auto-generated constructor stub    }    private long mmin, msecond;    private boolean run = false;    public void setTimes(long[] times) {        mmin = times[0];        msecond = times[1];    }    private void ComputeTime() {        msecond--;        if (msecond < 0) {            mmin--;            msecond = 59;        }    }    public boolean isRun() {        return run;    }    public void beginRun() {        this.run = true;        run();    }    public void stopRun() {        this.run = false;    }//多线程，时间按mm:ss格式显示    @Override    public void run() {        if (run) {            ComputeTime();            if (mmin>9&&msecond>9) {                String strTime = mmin + ":" + msecond;                this.setText(strTime);            }else if(mmin>9&&msecond<10){                String strTime = mmin + ":0"+ msecond;                this.setText(strTime);            }else if(mmin<10&&msecond>9) {                String strTime = "0"+mmin + ":"+ msecond;                this.setText(strTime);            }else if(mmin<10&&msecond<10){                String strTime = "0"+mmin + ":0"+ msecond;                this.setText(strTime);            }            postDelayed(this, 1000);        } else {            removeCallbacks(this);        }        if (mmin == 0 && msecond == 0) {            stopRun();        }        // Log.e("shijian:",getRemainTime());    }//回去剩余时间的分和秒    public long getRemainMinute() {        return mmin;    }    public long getRemainSecond(){        return msecond;    }}

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:background="@drawable/bg"    android:orientation="vertical"> <utils.TimerTextView            android:id="@+id/treattime"            android:layout_width="match_parent"            android:layout_height="wrap_content"            android:text="30:00"            android:gravity="center"            android:textSize="52sp"            android:textColor="#1987C9"            />            LinearLayout>

6、不同分辨率手机界面适配
转载：http://blog.csdn.net/lmj623565791/article/details/46695347；
注：有Navigation bar的手机需要获取手机实际分辨率(减去navigation bar占用的尺寸)后再编写一套value布局。

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