最近，隨着智能穿戴式設備、智能醫療以及智能家居的普及，藍牙開發在移動開中顯得非常的重要。由於公司需要，研究了一下，藍牙4.0在Android中的應用。
以下是我的一些總結。
1.先介紹一下關於藍牙4.0中的一些名詞吧：
(1)、GATT(Gneric Attibute Profile)
通過ble連接，讀寫屬性類小數據Profile通用的規範。現在所有的ble應用Profile 都是基於GATT
(2)、ATT(Attribute Protocal)
GATT是基於ATT Potocal的ATT針對BLE設備專門做的具體就是傳輸過程中使用盡量少的數據，每個屬性都有個唯一的UUID，屬性chartcteristics and Service的形式傳輸。
(3)、Service是Characteristic的集合。
(4)、Characteristic 特徵類型。
比如，有個藍牙ble的血壓計。他可能包括多個Servvice，每個Service有包括多個Characteristic
注意：藍牙ble只能支持Android 4.3以上的系統 SDK>=18
2.以下是開發的步驟：
2.1首先獲取BluetoothManager
複製代碼代碼如下:
BluetoothManager bluetoothManager = (BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE);
2.2獲取BluetoothAdapter
複製代碼代碼如下:
BluetoothAdapter mBluetoothAdapter = bluetoothManager.getAdapter();
2.3創建BluetoothAdapter.LeScanCallback
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private
BluetoothAdapter.LeScanCallback mLeScanCallback = new
BluetoothAdapter.LeScanCallback() { @Override public
void
onLeScan(final
BluetoothDevice device, int
rssi, final
byte[]
scanRecord) { runOnUiThread(new
Runnable() { @Override public
void
run() { try
{ String
struuid = NumberUtils.bytes2HexString(NumberUtils.reverseBytes(scanRecord)).replace("-",
"").toLowerCase();
if
(device!=null
&& struuid.contains(DEVICE_UUID_PREFIX.toLowerCase())) { mBluetoothDevices.add(device);
}
}
catch
(Exception e) { e.printStackTrace();
}
}
});
}
}; |
2.4.開始搜索設備。
複製代碼代碼如下:
mBluetoothAdapter.startLeScan(mLeScanCallback);
2.5.BluetoothDevice 描述了一個藍牙設備 提供了getAddress()設備Mac地址,getName()設備的名稱。
2.6開始連接設備
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/**
*
Connects to the GATT server hosted on the Bluetooth LE device. *
*
@param address *
The device address of the destination device. *
*
@return Return true if the connection is initiated successfully. The *
connection result is reported asynchronously through the *
{@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
*
callback. */public
boolean
connect(final
String address) { if
(mBluetoothAdapter == null
|| address == null)
{ Log.w(TAG,
"BluetoothAdapter
not initialized or unspecified address.");
return
false;
}
//
Previously connected device. Try to reconnect. (先前連接的設備。 嘗試重新連接) if
(mBluetoothDeviceAddress != null
&& address.equals(mBluetoothDeviceAddress) && mBluetoothGatt != null)
{ Log.d(TAG,
"Trying
to use an existing mBluetoothGatt for connection.");
if
(mBluetoothGatt.connect()) { mConnectionState
= STATE_CONNECTING; return
true;
}
else
{ return
false;
}
}
final
BluetoothDevice device = mBluetoothAdapter.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. mBluetoothGatt
= device.connectGatt(this,
false,
mGattCallback); Log.d(TAG,
"Trying
to create a new connection.");
mBluetoothDeviceAddress
= address; mConnectionState
= STATE_CONNECTING; return
true;
}
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2.7連接到設備之後獲取設備的服務(Service)和服務對應的Characteristic。
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//
Demonstrates how to iterate through the supported GATT //
Services/Characteristics. //
In this sample, we populate the data structure that is bound to the //
ExpandableListView //
on the UI. private
void
displayGattServices(List<BluetoothGattService> gattServices) { if
(gattServices == null)
return;
String
uuid = null;
ArrayList<HashMap<String,
String>> gattServiceData = new
ArrayList<>(); ArrayList<ArrayList<HashMap<String,
String>>> gattCharacteristicData = new
ArrayList<>(); mGattCharacteristics
= new
ArrayList<>(); //
Loops through available GATT Services. for
(BluetoothGattService gattService : gattServices) { HashMap<String,
String> currentServiceData = new
HashMap<>(); uuid
= gattService.getUuid().toString(); if
(uuid.contains("ba11f08c-5f14-0b0d-1080"))
{//服務的uuid
//System.out.println("this
gattService UUID is:" + gattService.getUuid().toString()); currentServiceData.put(LIST_NAME,
"Service_OX100");
currentServiceData.put(LIST_UUID,
uuid); gattServiceData.add(currentServiceData);
ArrayList<HashMap<String,
String>> gattCharacteristicGroupData = new
ArrayList<>(); List<BluetoothGattCharacteristic>
gattCharacteristics = gattService.getCharacteristics(); ArrayList<BluetoothGattCharacteristic>
charas = new
ArrayList<>(); //
Loops through available Characteristics. for
(BluetoothGattCharacteristic gattCharacteristic : gattCharacteristics) { charas.add(gattCharacteristic);
HashMap<String,
String> currentCharaData = new
HashMap<>(); uuid
= gattCharacteristic.getUuid().toString(); if
(uuid.toLowerCase().contains("cd01"))
{ currentCharaData.put(LIST_NAME,
"cd01");
}
else
if
(uuid.toLowerCase().contains("cd02"))
{ currentCharaData.put(LIST_NAME,
"cd02");
}
else
if
(uuid.toLowerCase().contains("cd03"))
{ currentCharaData.put(LIST_NAME,
"cd03");
}
else
if
(uuid.toLowerCase().contains("cd04"))
{ currentCharaData.put(LIST_NAME,
"cd04");
}
else
{ currentCharaData.put(LIST_NAME,
"write");
}
currentCharaData.put(LIST_UUID,
uuid); gattCharacteristicGroupData.add(currentCharaData);
}
mGattCharacteristics.add(charas);
gattCharacteristicData.add(gattCharacteristicGroupData);
mCharacteristicCD01
= gattService.getCharacteristic(UUID.fromString("0000cd01-0000-1000-8000-00805f9b34fb"));
mCharacteristicCD02
= gattService.getCharacteristic(UUID.fromString("0000cd02-0000-1000-8000-00805f9b34fb"));
mCharacteristicCD03
= gattService.getCharacteristic(UUID.fromString("0000cd03-0000-1000-8000-00805f9b34fb"));
mCharacteristicCD04
= gattService.getCharacteristic(UUID.fromString("0000cd04-0000-1000-8000-00805f9b34fb"));
mCharacteristicWrite
= gattService.getCharacteristic(UUID.fromString("0000cd20-0000-1000-8000-00805f9b34fb"));
//System.out.println("=======================Set
Notification=========================="); //
開始順序監聽，第一個：CD01 mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD01,
true);
mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD02,
true);
mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD03,
true);
mBluetoothLeService.setCharacteristicNotification(mCharacteristicCD04,
true);
}
}
}
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2.8獲取到特徵之後，找到服務中可以向下位機寫指令的特徵，向該特徵寫入指令。
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public
void
wirteCharacteristic(BluetoothGattCharacteristic characteristic) { if
(mBluetoothAdapter == null
|| mBluetoothGatt == null)
{ Log.w(TAG,
"BluetoothAdapter
not initialized");
return;
}
mBluetoothGatt.writeCharacteristic(characteristic);
}
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2.9寫入成功之後，開始讀取設備返回來的數據。
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private
final
BluetoothGattCallback mGattCallback = new
BluetoothGattCallback() { @Override public
void
onConnectionStateChange(BluetoothGatt gatt, int
status, int
newState) { String
intentAction; //System.out.println("=======status:"
+ status); if
(newState == BluetoothProfile.STATE_CONNECTED) { intentAction
= ACTION_GATT_CONNECTED; mConnectionState
= STATE_CONNECTED; broadcastUpdate(intentAction);
Log.i(TAG,
"Connected
to GATT server.");
//
Attempts to discover services after successful connection. Log.i(TAG,
"Attempting
to start service discovery:"
+ mBluetoothGatt.discoverServices()); }
else
if
(newState == BluetoothProfile.STATE_DISCONNECTED) { intentAction
= ACTION_GATT_DISCONNECTED; mConnectionState
= STATE_DISCONNECTED; Log.i(TAG,
"Disconnected
from GATT server.");
broadcastUpdate(intentAction);
}
}
@Override public
void
onServicesDiscovered(BluetoothGatt gatt, int
status) { if
(status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_GATT_SERVICES_DISCOVERED);
}
else
{ Log.w(TAG,
"onServicesDiscovered
received: "
+ status); }
}
//從特徵中讀取數據
@Override public
void
onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,
int
status) { //System.out.println("onCharacteristicRead");
if
(status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_DATA_AVAILABLE,
characteristic); }
}
//向特徵中寫入數據
@Override public
void
onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,
int
status) { //System.out.println("--------write
success----- status:" + status); }
/*
*
when connected successfully will callback this method this method can *
dealwith send password or data analyze *當連接成功將回調該方法
*/ @Override public
void
onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
broadcastUpdate(ACTION_DATA_AVAILABLE,
characteristic); if
(characteristic.getValue() != null)
{ //System.out.println(characteristic.getStringValue(0));
}
//System.out.println("--------onCharacteristicChanged-----");
}
@Override public
void
onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor,
int
status) { //System.out.println("onDescriptorWriteonDescriptorWrite
= " + status + ", descriptor =" + descriptor.getUuid().toString()); UUID
uuid = descriptor.getCharacteristic().getUuid(); if
(uuid.equals(UUID.fromString("0000cd01-0000-1000-8000-00805f9b34fb")))
{ broadcastUpdate(ACTION_CD01NOTIDIED);
}
else
if
(uuid.equals(UUID.fromString("0000cd02-0000-1000-8000-00805f9b34fb")))
{ broadcastUpdate(ACTION_CD02NOTIDIED);
}
else
if
(uuid.equals(UUID.fromString("0000cd03-0000-1000-8000-00805f9b34fb")))
{ broadcastUpdate(ACTION_CD03NOTIDIED);
}
else
if
(uuid.equals(UUID.fromString("0000cd04-0000-1000-8000-00805f9b34fb")))
{ broadcastUpdate(ACTION_CD04NOTIDIED);
}
}
@Override public
void
onReadRemoteRssi(BluetoothGatt gatt, int
rssi, int
status) { //System.out.println("rssi
= " + rssi); }
};
----------------------------------------------
//從特徵中讀取數據
@Override public
void
onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic,
int
status) { //System.out.println("onCharacteristicRead");
if
(status == BluetoothGatt.GATT_SUCCESS) { broadcastUpdate(ACTION_DATA_AVAILABLE,
characteristic); }
}
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2.10、斷開連接
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/**
*
Disconnects an existing connection or cancel a pending connection. The *
disconnection result is reported asynchronously through the *
{@code BluetoothGattCallback#onConnectionStateChange(android.bluetooth.BluetoothGatt, int, int)}
*
callback. */ public
void
disconnect() { if
(mBluetoothAdapter == null
|| mBluetoothGatt == null)
{ Log.w(TAG,
"BluetoothAdapter
not initialized");
return;
}
mBluetoothGatt.disconnect();
}
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2.11、數據的轉換方法
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//
byte轉十六進制字符串 public
static
String bytes2HexString(byte[]
bytes) { String
ret = "";
for
(byte
aByte : bytes) { String
hex = Integer.toHexString(aByte & 0xFF);
if
(hex.length() == 1)
{ hex
= '0'
+ hex; }
ret
+= hex.toUpperCase(Locale.CHINA); }
return
ret; }
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/**
*
將16進制的字符串轉換爲字節數組 *
*
@param message *
@return 字節數組 */ public
static
byte[]
getHexBytes(String message) { int
len = message.length() / 2;
char[]
chars = message.toCharArray(); String[]
hexStr = new
String[len]; byte[]
bytes = new
byte[len];
for
(int
i = 0,
j = 0;
j < len; i += 2,
j++) { hexStr[j]
= ""
+ chars[i] + chars[i + 1];
bytes[j]
= (byte)
Integer.parseInt(hexStr[j], 16);
}
return
bytes; } |
大概整體就是如上的步驟，但是也是要具體根據廠家的協議來實現通信的過程。
就拿一個我們項目中的demo說一下。
一個藍牙ble的血壓計。 上位機---手機 下位機 -- 血壓計
1.血壓計與手機連接藍牙之後。
2.上位機主動向下位機發送一個身份驗證指令，下位機收到指令後開始給上位做應答，
3.應答成功，下位機會將測量的血壓數據傳送到上位機。
4.最後斷開連接。