安卓通讯开发——蓝牙
通讯（Connectivity）
除了提供标准的网络连接外，Android还提供API，让您的应用程序能够使用蓝牙、NFC、Wi-Fi、P2P、USB和SIP等协议与其他设备进行连接和交互。
In addition to providing standard network connectivity, Android provides APIs to let your app connect and interact with other devices with protocols such as Bluetooth, NFC, Wi-Fi P2P, USB, and SIP.
https://developer.android.google.cn/guide/topics/connectivity
首先，什么是蓝牙？
- 蓝牙技术最初由电信巨头爱立信公司于1994年创制，当时是作为RS232数据线的替代方案
- 是一种支持设备短距离通信（一般10m内，且无阻隔媒介）的无线电技术。
- 使用2.4—2.485GHz的ISM波段的UHF无线电波
- 能在包括移动电话、PDA、无线耳机、笔记本电脑等众多设备之间进行无线信息交换。
- 利用“蓝牙”技术，能够有效的简化移动通信终端设备之间的通信，也能够成功的简化设备与Internet之间的通信，这样数据传输变得更加迅速高效，为无线通信拓宽道路。
注意：Android 2.0 引入蓝牙接口，在开发时，需要真机测试，如果需要数据传输，还需要两台机器，另外蓝牙下哟硬件支持。
蓝牙
https://developer.android.google.cn/guide/topics/connectivity/bluetooth
Android 平台包含蓝牙网络堆栈支持，凭借此项支持，设备能以无线方式与其他蓝牙设备交换数据。应用框架提供了通过 Android Bluetooth API 访问蓝牙功能的途径。 这些 API 允许应用以无线方式连接到其他蓝牙设备，从而实现点到点和多点无线功能。
使用 Bluetooth API，Android 应用可执行以下操作：
- 扫描其他蓝牙设备
- 查询本地蓝牙适配器的配对蓝牙设备
- 建立 RFCOMM 通道
- 通过服务发现连接到其他设备
- 与其他设备进行双向数据传输
- 管理多个连接
本文将介绍如何使用传统蓝牙。传统蓝牙适用于电池使用强度较大的操作，例如 Android 设备之间的流式传输和通信等。 针对具有低功耗要求的蓝牙设备，Android 4.3（API 级别 18）中引入了面向低功耗蓝牙的 API 支持。 如需了解更多信息，请参阅低功耗蓝牙。
蓝牙设备操作
权限
要在应用中使用蓝牙功能，必须声明蓝牙权限
BLUETOOTH。您需要此权限才能执行任何蓝牙通信，例如请求连接、接受连接和传输数据等。如果您希望您的应用启动设备发现或操作蓝牙设置，则还必须声明
BLUETOOTH_ADMIN权限。 大多数应用需要此权限仅仅为了能够发现本地蓝牙设备。 除非该应用是将要应用户请求修改蓝牙设置的“超级管理员”，否则不应使用此权限所授予的其他能力。 注：如果要使用BLUETOOTH_ADMIN权限，则还必须拥有BLUETOOTH权限。
打开操作
//第一种方法（弹出对话框提示信息）
Intent enabler = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
//打开本机的蓝牙发现功能(默认打开120秒,一个应用程序可以设定的最长持续时间为3600秒)
//enabler.putExtra(BluetoothAdapter.EXTRA SCOVERABLE_DURATION, 300)
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
startActivity(enabler,REQUEST_ENABLE);
//第二种方法（直接打开，没有提示）
BluetoothAdapter bluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
bluetoothAdapter.enable();上面是老的API文档提供的方法，下面是目前API文档的提供的写法
BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (mBluetoothAdapter == null) {
// Device does not support Bluetooth
}
if (!mBluetoothAdapter.isEnabled()) {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
（有提示信息的如图所示）
关闭操作
BluetoothAdapter _bluetooth = BluetoothAdapter.getDefaultAdapter();
_bluetooth.disable ():搜索操作
BluetoothAdapter _bluetooth = BluetoothAdapter.getDefaultAdapter();
_bluetooth.startDiscovery();getBondedDevices()为扫描当前配对列表
蓝牙通讯案例
蓝牙设备进行连接，需要一个唯一的UUID，在本案例中可以随便写，但是需要保证两个设备是相同的。
关于 UUID
通用唯一标识符 (UUID) 是用于唯一标识信息的字符串 ID 的 128 位标准化格式。 UUID 的特点是其足够庞大，因此您可以选择任意随机值而不会发生冲突。 在此示例中，它被用于唯一标识应用的蓝牙服务。 要获取 UUID 以用于您的应用，您可以使用网络上的众多随机 UUID 生成器之一，然后使用
fromString(String)初始化一个UUID。下面列出一些常用的蓝牙服务UUID：
ServiceDiscoveryServerServiceClassID_UUID = '{00001000-0000-1000-8000-00805F9B34FB}'
BrowseGroupDescriptorServiceClassID_UUID = '{00001001-0000-1000-8000-00805F9B34FB}'
PublicBrowseGroupServiceClass_UUID = '{00001002-0000-1000-8000-00805F9B34FB}'#蓝牙串口服务
SerialPortServiceClass_UUID = '{00001101-0000-1000-8000-00805F9B34FB}'LANAccessUsingPPPServiceClass_UUID = '{00001102-0000-1000-8000-00805F9B34FB}'
#拨号网络服务
DialupNetworkingServiceClass_UUID = '{00001103-0000-1000-8000-00805F9B34FB}'#信息同步服务
IrMCSyncServiceClass_UUID = '{00001104-0000-1000-8000-00805F9B34FB}'SDP_OBEXObjectPushServiceClass_UUID = '{00001105-0000-1000-8000-00805F9B34FB}'
#文件传输服务
OBEXFileTransferServiceClass_UUID = '{00001106-0000-1000-8000-00805F9B34FB}'IrMCSyncCommandServiceClass_UUID = '{00001107-0000-1000-8000-00805F9B34FB}'
SDP_HeadsetServiceClass_UUID = '{00001108-0000-1000-8000-00805F9B34FB}'
CordlessTelephonyServiceClass_UUID = '{00001109-0000-1000-8000-00805F9B34FB}'
SDP_AudioSourceServiceClass_UUID = '{0000110A-0000-1000-8000-00805F9B34FB}'
SDP_AudioSinkServiceClass_UUID = '{0000110B-0000-1000-8000-00805F9B34FB}'
SDP_AVRemoteControlTargetServiceClass_UUID = '{0000110C-0000-1000-8000-00805F9B34FB}'
SDP_AdvancedAudioDistributionServiceClass_UUID = '{0000110D-0000-1000-8000-00805F9B34FB}'
SDP_AVRemoteControlServiceClass_UUID = '{0000110E-0000-1000-8000-00805F9B34FB}'
VideoConferencingServiceClass_UUID = '{0000110F-0000-1000-8000-00805F9B34FB}'
IntercomServiceClass_UUID = '{00001110-0000-1000-8000-00805F9B34FB}'#蓝牙传真服务
FaxServiceClass_UUID = '{00001111-0000-1000-8000-00805F9B34FB}'HeadsetAudioGatewayServiceClass_UUID = '{00001112-0000-1000-8000-00805F9B34FB}'
WAPServiceClass_UUID = '{00001113-0000-1000-8000-00805F9B34FB}'
WAPClientServiceClass_UUID = '{00001114-0000-1000-8000-00805F9B34FB}'#个人局域网服务
PANUServiceClass_UUID = '{00001115-0000-1000-8000-00805F9B34FB}'#个人局域网服务
NAPServiceClass_UUID = '{00001116-0000-1000-8000-00805F9B34FB}'#个人局域网服务
GNServiceClass_UUID = '{00001117-0000-1000-8000-00805F9B34FB}'DirectPrintingServiceClass_UUID = '{00001118-0000-1000-8000-00805F9B34FB}'
ReferencePrintingServiceClass_UUID = '{00001119-0000-1000-8000-00805F9B34FB}'
ImagingServiceClass_UUID = '{0000111A-0000-1000-8000-00805F9B34FB}'
ImagingResponderServiceClass_UUID = '{0000111B-0000-1000-8000-00805F9B34FB}'
ImagingAutomaticArchiveServiceClass_UUID = '{0000111C-0000-1000-8000-00805F9B34FB}'
ImagingReferenceObjectsServiceClass_UUID = '{0000111D-0000-1000-8000-00805F9B34FB}'
SDP_HandsfreeServiceClass_UUID = '{0000111E-0000-1000-8000-00805F9B34FB}'
HandsfreeAudioGatewayServiceClass_UUID = '{0000111F-0000-1000-8000-00805F9B34FB}'
DirectPrintingReferenceObjectsServiceClass_UUID = '{00001120-0000-1000-8000-00805F9B34FB}'
ReflectedUIServiceClass_UUID = '{00001121-0000-1000-8000-00805F9B34FB}'
BasicPringingServiceClass_UUID = '{00001122-0000-1000-8000-00805F9B34FB}'
PrintingStatusServiceClass_UUID = '{00001123-0000-1000-8000-00805F9B34FB}'#人机输入服务
HumanInterfaceDeviceServiceClass_UUID = '{00001124-0000-1000-8000-00805F9B34FB}'HardcopyCableReplacementServiceClass_UUID = '{00001125-0000-1000-8000-00805F9B34FB}'
#蓝牙打印服务
HCRPrintServiceClass_UUID = '{00001126-0000-1000-8000-00805F9B34FB}'HCRScanServiceClass_UUID = '{00001127-0000-1000-8000-00805F9B34FB}'
CommonISDNAccessServiceClass_UUID = '{00001128-0000-1000-8000-00805F9B34FB}'
VideoConferencingGWServiceClass_UUID = '{00001129-0000-1000-8000-00805F9B34FB}'
UDIMTServiceClass_UUID = '{0000112A-0000-1000-8000-00805F9B34FB}'
UDITAServiceClass_UUID = '{0000112B-0000-1000-8000-00805F9B34FB}'
AudioVideoServiceClass_UUID = '{0000112C-0000-1000-8000-00805F9B34FB}'
SIMAccessServiceClass_UUID = '{0000112D-0000-1000-8000-00805F9B34FB}'
PnPInformationServiceClass_UUID = '{00001200-0000-1000-8000-00805F9B34FB}'
GenericNetworkingServiceClass_UUID = '{00001201-0000-1000-8000-00805F9B34FB}'
GenericFileTransferServiceClass_UUID = '{00001202-0000-1000-8000-00805F9B34FB}'
GenericAudioServiceClass_UUID = '{00001203-0000-1000-8000-00805F9B34FB}'
GenericTelephonyServiceClass_UUID = '{00001204-0000-1000-8000-00805F9B34FB}'
客户端
布局，准备一个仅作为标识的文本框，一个输入框，和一个提示当前状态的文本框（操作的结果及进度...）最后在来一个按钮
package com.example.a5_21bluetooth;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.lang.ref.WeakReference;
import java.util.UUID;
public class Client extends AppCompatActivity {
private static final int CONN_SUCCESS = 0x1;
private static final int CONN_FAIL = 0x2;
private static final int RECEIVER_INFO = 0x3;
private static final int SET_EDITTEXT_NULL = 0x4;
private static Button send;
private static TextView client_state;
private static EditText client_send;
BluetoothAdapter bluetooth = null;//本地蓝牙设备
BluetoothDevice device = null;//远程蓝牙设备
BluetoothSocket socket = null;//蓝牙设备Socket客户端
//输入输出流
PrintStream out;
BufferedReader in;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_client);
setTitle("蓝牙客户端");
client_state = findViewById(R.id.client_state);
client_send = findViewById(R.id.client_send);
send = findViewById(R.id.send);
init();
}
//创建蓝牙客户端端的Socket
private void init() {
client_state.setText("客户端已启动，正在等待连接...\n");
new Thread(new Runnable() {
@Override
public void run() {
//1.得到本地蓝牙设备的默认适配器
bluetooth = BluetoothAdapter.getDefaultAdapter();
//2.通过本地蓝牙设备得到远程蓝牙设备，把“输入服务器端的设备地址”换成另一台手机的mac地址
device = bluetooth.getRemoteDevice("输入服务器端的设备地址");
//3.根据UUID创建并返回一个BoluetoothSocket
try {
socket = device.createRfcommSocketToServiceRecord(UUID.fromString("00000000-2527-eef3-ffff-ffffe3160865"));
if (socket != null) {
// 连接
socket.connect();
//处理客户端输出流
out = new PrintStream(socket.getOutputStream());
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
}
handler.sendEmptyMessage(CONN_SUCCESS);
} catch (IOException e) {
e.printStackTrace();
Message msg = handler.obtainMessage(CONN_FAIL, e.getLocalizedMessage());
handler.sendMessage(msg);
}
}
}).start();
}
//防止内存泄漏 正确的使用方法
private final MyHandler handler = new MyHandler(this);
public class MyHandler extends Handler {
//软引用
WeakReference weakReference;
public MyHandler(Client activity) {
weakReference = new WeakReference(activity);
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Client activity = weakReference.get();
if (activity != null) {
switch (msg.what) {
case RECEIVER_INFO:
setInfo(msg.obj.toString() + "\n");
break;
case SET_EDITTEXT_NULL:
client_send.setText("");
break;
case CONN_SUCCESS:
setInfo("连接成功！\n");
send.setEnabled(true);
System.out.println("name" + device.getName());
System.out.println("Uuids" + device.getUuids());
System.out.println("Address" + device.getAddress());
new Thread(new ReceiverInfoThread()).start();
break;
case CONN_FAIL:
setInfo("连接失败！\n");
setInfo(msg.obj.toString() + "\n");
break;
default:
break;
}
}
}
}
private boolean isReceiver = true;
//接收信息的线程
class ReceiverInfoThread implements Runnable {
@Override
public void run() {
String info = null;
while (isReceiver) {
try {
System.out.println("--ReceiverInfoThread start --");
info = in.readLine();
System.out.println("--ReceiverInfoThread read --");
Message msg = handler.obtainMessage(RECEIVER_INFO, info);
handler.sendMessage(msg);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public void send(View v) {
final String content = client_send.getText().toString();
if (TextUtils.isEmpty(content)) {
Toast.makeText(this, "不能发送空消息", Toast.LENGTH_LONG).show();
return;
}
new Thread(new Runnable() {
@Override
public void run() {
out.println(content);
out.flush();
handler.sendEmptyMessage(SET_EDITTEXT_NULL);
}
}).start();
}
private void setInfo(String info) {
StringBuffer sb = new StringBuffer();
sb.append(client_state.getText());
sb.append(info);
client_state.setText(sb);
}
}
服务器端
说是说服务器端，在这个案例实际上基本上没差2333（换了个名字）
package com.example.a5_21bluetooth;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.lang.ref.WeakReference;
import java.util.UUID;
public class Server extends AppCompatActivity {
private static final int CONN_SUCCESS = 0x1;
private static final int CONN_FAIL = 0x2;
private static final int RECEIVER_INFO = 0x3;
private static final int SET_EDITTEXT_NULL = 0x4;
private static Button send;
private static TextView server_state;
private static EditText server_send;
BluetoothAdapter bluetooth = null;//本地蓝牙设备
BluetoothServerSocket serverSocket = null;//蓝牙设备Socket服务端
BluetoothSocket socket = null;//蓝牙设备Socket客户端
//输入输出流
PrintStream out;
BufferedReader in;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_server);
setTitle("蓝牙服务端");
server_state = (TextView) findViewById(R.id.server_state);
server_send = (EditText) findViewById(R.id.server_send);
send = (Button) findViewById(R.id.send);
init();
}
//创建蓝牙服务器端的Socket
private void init() {
server_state.setText("服务器已启动，正在等待连接...\n");
new Thread(new Runnable() {
@Override
public void run() {
//1.得到本地设备
bluetooth = BluetoothAdapter.getDefaultAdapter();
//2.创建蓝牙Socket服务器
try {
serverSocket = bluetooth.listenUsingRfcommWithServiceRecord("text", UUID.fromString("00000000-2527-eef3-ffff-ffffe3160865"));
//3.阻塞等待Socket客户端请求
socket = serverSocket.accept();
if (socket != null) {
out = new PrintStream(socket.getOutputStream());
in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
}
handler.sendEmptyMessage(CONN_SUCCESS);
} catch (IOException e) {
e.printStackTrace();
Message msg = handler.obtainMessage(CONN_FAIL, e.getLocalizedMessage());
handler.sendMessage(msg);
}
}
}).start();
}
//防止内存泄漏 正确的使用方法
private final MyHandler handler = new MyHandler(this);
public class MyHandler extends Handler {
//软引用
WeakReference weakReference;
public MyHandler(Server activity) {
weakReference = new WeakReference(activity);
}
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Server activity = weakReference.get();
if (activity != null) {
switch (msg.what) {
case RECEIVER_INFO:
setInfo(msg.obj.toString() + "\n");
break;
case SET_EDITTEXT_NULL:
server_send.setText("");
break;
case CONN_SUCCESS:
setInfo("连接成功！\n");
send.setEnabled(true);
new Thread(new ReceiverInfoThread()).start();
break;
case CONN_FAIL:
setInfo("连接失败！\n");
setInfo(msg.obj.toString() + "\n");
break;
default:
break;
}
}
}
}
private boolean isReceiver = true;
class ReceiverInfoThread implements Runnable {
@Override
public void run() {
String info = null;
while (isReceiver) {
try {
info = in.readLine();
Message msg = handler.obtainMessage(RECEIVER_INFO, info);
handler.sendMessage(msg);
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
public void send(View v) {
final String content = server_send.getText().toString();
if (TextUtils.isEmpty(content)) {
Toast.makeText(Server.this, "不能发送空消息", Toast.LENGTH_LONG).show();
return;
}
new Thread(new Runnable() {
@Override
public void run() {
out.println(content);
out.flush();
handler.sendEmptyMessage(SET_EDITTEXT_NULL);
}
}).start();
}
private void setInfo(String info) {
StringBuffer sb = new StringBuffer();
sb.append(server_state.getText());
sb.append(info);
server_state.setText(sb);
}
}
效果不太方便展示，需要两台手机大概界面如下，成功的话会输出对应的内容，通过输入框和按钮可以在两个端间进行交互
