最近，随着智能穿戴式设备、智能医疗以及智能家居的普及，蓝牙开发在移动开中显得非常的重要。由于公司需要，研究了一下，蓝牙4.0在android中的应用。
以下是我的一些总结。
1.先介绍一下关于蓝牙4.0中的一些名词吧：
(1)、gatt(gneric attibute profile)
通过ble连接，读写属性类小数据profile通用的规范。现在所有的ble应用profile 都是基于gatt
(2)、att(attribute protocal)
gatt是基于att potocal的att针对ble设备专门做的具体就是传输过程中使用尽量少的数据，每个属性都有个唯一的uuid，属性chartcteristics and service的形式传输。
(3)、service是characteristic的集合。
(4)、characteristic 特征类型。
比如，有个蓝牙ble的血压计。他可能包括多个servvice，每个service有包括多个characteristic
注意：蓝牙ble只能支持android 4.3以上的系统 sdk>=18
2.以下是开发的步骤：
2.1首先获取bluetoothmanager
复制代码 代码如下:
bluetoothmanager bluetoothmanager = (bluetoothmanager) getsystemservice(context.bluetooth_service);
2.2获取bluetoothadapter
复制代码 代码如下:
bluetoothadapter mbluetoothadapter = bluetoothmanager.getadapter();
2.3创建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.开始搜索设备。
复制代码 代码如下:
mbluetoothadapter.startlescan(mlescancallback);
2.5.bluetoothdevice 描述了一个蓝牙设备 提供了getaddress()设备mac地址,getname()设备的名称。
2.6开始连接设备
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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. (先前连接的设备。 尝试重新连接) 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; } |
2.7连接到设备之后获取设备的服务(service)和服务对应的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")) {//服务的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=========================="); // 开始顺序监听，第一个：cd01 mbluetoothleservice.setcharacteristicnotification(mcharacteristiccd01, true); mbluetoothleservice.setcharacteristicnotification(mcharacteristiccd02, true); mbluetoothleservice.setcharacteristicnotification(mcharacteristiccd03, true); mbluetoothleservice.setcharacteristicnotification(mcharacteristiccd04, true); } } } |
2.8获取到特征之后，找到服务中可以向下位机写指令的特征，向该特征写入指令。
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public void wirtecharacteristic(bluetoothgattcharacteristic characteristic) { if (mbluetoothadapter == null || mbluetoothgatt == null) { log.w(tag, "bluetoothadapter not initialized"); return; } mbluetoothgatt.writecharacteristic(characteristic); } |
2.9写入成功之后，开始读取设备返回来的数据。
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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); } } //从特征中读取数据 @override public void oncharacteristicread(bluetoothgatt gatt, bluetoothgattcharacteristic characteristic, int status) { //system.out.println("oncharacteristicread"); if (status == bluetoothgatt.gatt_success) { broadcastupdate(action_data_available, characteristic); } } //向特征中写入数据 @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 *当连接成功将回调该方法 */ @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); } }; ---------------------------------------------- //从特征中读取数据 @override public void oncharacteristicread(bluetoothgatt gatt, bluetoothgattcharacteristic characteristic, int status) { //system.out.println("oncharacteristicread"); if (status == bluetoothgatt.gatt_success) { broadcastupdate(action_data_available, characteristic); } } |
2.10、断开连接
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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(); } |
2.11、数据的转换方法
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// byte转十六进制字符串 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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/** * 将16进制的字符串转换为字节数组 * * @param message * @return 字节数组 */ 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; } |
大概整体就是如上的步骤，但是也是要具体根据厂家的协议来实现通信的过程。
就拿一个我们项目中的demo说一下。
一个蓝牙ble的血压计。 上位机---手机 下位机 -- 血压计
1.血压计与手机连接蓝牙之后。
2.上位机主动向下位机发送一个身份验证指令，下位机收到指令后开始给上位做应答，
3.应答成功，下位机会将测量的血压数据传送到上位机。
4.最后断开连接。
希望本文对大家学习android蓝牙技术有所帮助。
