原文链接https://www.shanya.world/archives/3a0ead9f.html
Android Studio 的蓝牙串口通信
这次做项目用到了蓝牙串口，折腾了两天总算弄出来了，记录一下方便以后回顾。
获取相关权限
获取蓝牙权限
在 AndroidManifest.xml文件中加入如下代码，（其实这俩句可以先不加，在工程中写到相应语句的时候可以Alt+Enter添加）
<uses-permission android:name="android.permission.BLUETOOTH" />
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
再加上定位权限，这是Android 6.0 以上一定需要注意的地方，同时最好在代码里加上判断是否获取定位权限的代码（就是这个该死的玩意儿耽误我好长时间）
AndroidManifest.xml中
<uses-feature android:name="android.hardware.location.gps" />
<uses-feature
android:name="android.hardware.bluetooth_le"
android:required="true" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
判断是否获取定位权限（这里我是写在了扫描未配对蓝牙设备的地方，当然也可以直接放在程序刚开始）
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){//未开启定位权限
//开启定位权限,200是标识码
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},200);
}else{
// 显示其它设备（未配对设备）列表
findViewById(R.id.textView).setVisibility(View.VISIBLE);
// 关闭再进行的服务查找
if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
}
mBluetoothAdapter.startDiscovery();
}
}
上述判断发现未开启之后会自动回调函数区开启，这里手动实现代码如下
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode){
case 200:
if(grantResults[0] == PackageManager.PERMISSION_GRANTED){
doDiscovery();
}else{
finish();
}
break;
default:
}
}
权限方面的事情完了（我并不是在程序刚开始的地方考虑的，这一点很不好，后续版本会改掉 ，这里就懒得弄了，嘿嘿）
接下来判断蓝牙是否打开
//如果打不开蓝牙提示信息，结束程序
if (mBluetoothAdapter == null){
Toast.makeText(getApplicationContext(),"无法打开手机蓝牙，请确认手机是否有蓝牙功能！",Toast.LENGTH_SHORT).show();
finish();
return;
}
连接按钮的响应
final Button connectButton = findViewById(R.id.connectButton);
connectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mBluetoothAdapter.isEnabled() == false) {
Toast.makeText(getApplicationContext(), " 请先打开蓝牙", Toast.LENGTH_LONG).show();
return;
}
//如果未连接设备则打开DevicesListActivity搜索设备
if (mBluetoothSocket == null) {
Intent serveIntent = new Intent(getApplicationContext(), DevicesListActivity.class); //跳转活动
startActivityForResult(serveIntent, 1); //设置返回宏定义
} else {
//关闭连接socket
try {
bRun = false;
Thread.sleep(2000);
is.close();
mBluetoothSocket.close();
mBluetoothSocket = null;
connectButton.setText("连接");
} catch (InterruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
});
发送按钮响应
Button sendButton = (Button) findViewById(R.id.sendButton);
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int n = 0;
if (mBluetoothSocket == null) {
Toast.makeText(getApplicationContext(), "请先连接设备", Toast.LENGTH_SHORT).show();
return;
}
if (sendEditText.getText().length() == 0) {
Toast.makeText(getApplicationContext(), "请先输入数据", Toast.LENGTH_SHORT).show();
return;
}
try {
OutputStream os = mBluetoothSocket.getOutputStream(); //蓝牙连接输出流
byte[] bos = sendEditText.getText().toString().getBytes();
for (int i = 0; i < bos.length; i++) {
if (bos[i] == 0x0a) n++;
}
byte[] bos_new = new byte[bos.length + n];
n = 0;
for (int i = 0; i < bos.length; i++) { //手机中换行为0a,将其改为0d 0a后再发送
if (bos[i] == 0x0a) {
bos_new[n] = 0x0d;
n++;
bos_new[n] = 0x0a;
} else {
bos_new[n] = bos[i];
}
n++;
}
os.write(bos_new);
} catch (IOException e) {
e.printStackTrace();
}
}
});
设备可以被搜索设置（这里就看个人需求了，我是没用上这个）
new Thread(){
public void run(){
if(mBluetoothAdapter.isEnabled()==false){
mBluetoothAdapter.enable();
}
}
}.start();
接收活动结果，主要是扫面活动传来的连接信息
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case 1: //连接结果，由DeviceListActivity设置返回
// 响应返回结果
if (resultCode == Activity.RESULT_OK) { //连接成功，由DeviceListActivity设置返回
// MAC地址，由DeviceListActivity设置返回
String address = data.getExtras().getString(DevicesListActivity.EXTRA_DEVICE_ADDRESS);
// 得到蓝牙设备句柄
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(address);
// 用服务号得到socket
try {
mBluetoothSocket = mBluetoothDevice.createRfcommSocketToServiceRecord(UUID.fromString(MY_UUID));
} catch (IOException e) {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
}
//连接socket
Button connectButton = findViewById(R.id.connectButton);
try {
mBluetoothSocket.connect();
Toast.makeText(this, "连接" + mBluetoothDevice.getName() + "成功！", Toast.LENGTH_SHORT).show();
connectButton.setText("断开");
} catch (IOException e) {
try {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
mBluetoothSocket.close();
mBluetoothSocket = null;
} catch (IOException ee) {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
}
return;
}
//打开接收线程
try {
is = mBluetoothSocket.getInputStream(); //得到蓝牙数据输入流
} catch (IOException e) {
Toast.makeText(this, "接收数据失败！", Toast.LENGTH_SHORT).show();
return;
}
if (bThread == false) {
readThread.start();
bThread = true;
} else {
bRun = true;
}
}
break;
default:
break;
}
}
接收线程
//接收数据线程
Thread readThread=new Thread(){
public void run(){
int num = 0;
byte[] buffer = new byte[1024];
byte[] buffer_new = new byte[1024];
int i = 0;
int n = 0;
bRun = true;
//接收线程
while(true){
try{
while(is.available()==0){
while(bRun == false){}
}
while(true){
if(!bThread)//跳出循环
return;
num = is.read(buffer); //读入数据
n=0;
String s0 = new String(buffer,0,num);
for(i=0;i<num;i++){
if((buffer[i] == 0x0d)&&(buffer[i+1]==0x0a)){
buffer_new[n] = 0x0a;
i++;
}else{
buffer_new[n] = buffer[i];
}
n++;
}
String s = new String(buffer_new,0,n);
smsg+=s; //写入接收缓存
if(is.available()==0)break; //短时间没有数据才跳出进行显示
}
//发送显示消息，进行显示刷新
handler.sendMessage(handler.obtainMessage());
}catch(IOException e){
}
}
}
};
消息显示的处理队列
Handler handler= new Handler(){
public void handleMessage(Message msg){
super.handleMessage(msg);
tv_in.setText(smsg); //显示数据
scrollView.scrollTo(0,tv_in.getMeasuredHeight()); //跳至数据最后一页
}
};
至此，接收发送部分已经全部结束，然后就是扫描设备部分了
这部分我直接贴出整个活动的代码了 注释比较齐全 就不哔哔了
package com.example.btcontroller;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import android.Manifest;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Set;
public class DevicesListActivity extends AppCompatActivity {
private static final String TAG = "DevicesListActivity";
public static String EXTRA_DEVICE_ADDRESS = "设备地址";
//成员域
private BluetoothAdapter mBluetoothAdapter; //蓝牙适配器
private ArrayAdapter<String> mPairedDevicesArrayAdapter; //已配对的设备适配器
private ArrayAdapter<String> mUnPairedDevicesArrayAdapter; //未配对的设备适配器
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_devices_list);
//设定默认返回值为取消
setResult(Activity.RESULT_CANCELED);
// 初使化设备适配器存储数组
mPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
mUnPairedDevicesArrayAdapter = new ArrayAdapter<String>(this, R.layout.device_name);
// 设置已配队设备列表
ListView pairedListView = (ListView) findViewById(R.id.pairedListView);
pairedListView.setAdapter(mPairedDevicesArrayAdapter);
pairedListView.setOnItemClickListener( mDeviceClickListener);
// 设置新查找设备列表
ListView newDevicesListView = (ListView) findViewById(R.id.unPairedListView);
newDevicesListView.setAdapter(mUnPairedDevicesArrayAdapter);
newDevicesListView.setOnItemClickListener(mDeviceClickListener);
// 注册接收查找到设备action接收器
this.registerReceiver(mReceiver, new IntentFilter(BluetoothDevice.ACTION_FOUND));
// 注册查找结束action接收器
//filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
this.registerReceiver(mReceiver, new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED));
this.registerReceiver(mReceiver, new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_STARTED));
// 得到本地蓝牙句柄
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
// 得到已配对蓝牙设备列表
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
//添加已配对设备到列表并显示
if (pairedDevices.size() > 0) {
findViewById(R.id.pairedListView).setVisibility(View.VISIBLE);
for (BluetoothDevice device : pairedDevices) {
mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
} else {
String noDevices = "没有找到已配对的设备。" ;
mPairedDevicesArrayAdapter.add(noDevices);
}
//取消按键的响应函数
Button cancelButton = (Button) findViewById(R.id.cancelButton);
cancelButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
});
}
@Override
protected void onDestroy() {
super.onDestroy();
// 关闭服务查找
if (mBluetoothAdapter != null) {
mBluetoothAdapter.cancelDiscovery();
}
// 注销action接收器
this.unregisterReceiver(mReceiver);
}
/**
* 开始服务和设备查找
*/
private void doDiscovery() {
// if (D) Log.d(TAG, "doDiscovery()");
// 在窗口显示查找中信息
setTitle("查找设备中...");
if(ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED){//未开启定位权限
//开启定位权限,200是标识码
ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.ACCESS_FINE_LOCATION},200);
}else{
// 显示其它设备（未配对设备）列表
findViewById(R.id.textView).setVisibility(View.VISIBLE);
// 关闭再进行的服务查找
if (mBluetoothAdapter.isDiscovering()) {
mBluetoothAdapter.cancelDiscovery();
}
mBluetoothAdapter.startDiscovery();
}
}
//加载菜单
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main,menu);
return true;
}
//菜单项的响应
@Override
public boolean onOptionsItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()){
case R.id.scanItem:
doDiscovery();
break;
default:
}
return true;
}
// 选择设备响应函数
private AdapterView.OnItemClickListener mDeviceClickListener = new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> av, View v, int arg2, long arg3) {
// 准备连接设备，关闭服务查找
mBluetoothAdapter.cancelDiscovery();
// 得到mac地址
String info = ((TextView) v).getText().toString();
String address = info.substring(info.length() - 17);
// 设置返回数据
Intent intent = new Intent();
intent.putExtra("设备地址", address);
// 设置返回值并结束程序
setResult(Activity.RESULT_OK, intent);
finish();
}
};
// 查找到设备和搜索完成action监听器
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
// 查找到设备action
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
// 得到蓝牙设备
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
// 如果是已配对的则略过，已得到显示，其余的在添加到列表中进行显示
if (device.getBondState() != BluetoothDevice.BOND_BONDED) {
mUnPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}else{ //添加到已配对设备列表
mPairedDevicesArrayAdapter.add(device.getName() + "\n" + device.getAddress());
}
// 搜索完成action
} else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
setTitle("选择要连接的设备");
if (mUnPairedDevicesArrayAdapter.getCount() == 0) {
String noDevices = "没有找到新设备";
mUnPairedDevicesArrayAdapter.add(noDevices);
}
}
}
};
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode){
case 200:
if(grantResults[0] == PackageManager.PERMISSION_GRANTED){
doDiscovery();
}else{
finish();
}
break;
default:
}
}
}
主活动的代码
package com.example.btcontroller;
import androidx.appcompat.app.AppCompatActivity;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ScrollView;
import android.widget.TextView;
import android.widget.Toast;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
public class MainActivity extends AppCompatActivity {
private final static String MY_UUID = "00001101-0000-1000-8000-00805F9B34FB"; //SPP服务UUID号
private BluetoothAdapter mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter(); //获取蓝牙实例
private EditText sendEditText; //创建发送 句柄
private TextView tv_in; //接收显示句柄
private ScrollView scrollView; //翻页句柄
private String smsg = ""; //显示用数据缓存
BluetoothDevice mBluetoothDevice = null; //蓝牙设备
BluetoothSocket mBluetoothSocket = null; //蓝牙通信Socket
boolean bRun = true; //运行状态
boolean bThread = false; //读取线程状态
private InputStream is; //输入流，用来接收蓝牙数据
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取控件ID
sendEditText = findViewById(R.id.sendEditText);
scrollView = findViewById(R.id.receiveScrolView);
tv_in = findViewById(R.id.in);
//如果打不开蓝牙提示信息，结束程序
if (mBluetoothAdapter == null){
Toast.makeText(getApplicationContext(),"无法打开手机蓝牙，请确认手机是否有蓝牙功能！",Toast.LENGTH_SHORT).show();
finish();
return;
}
//连接按钮响应
final Button connectButton = findViewById(R.id.connectButton);
connectButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mBluetoothAdapter.isEnabled() == false) {
Toast.makeText(getApplicationContext(), " 请先打开蓝牙", Toast.LENGTH_LONG).show();
return;
}
//如果未连接设备则打开DevicesListActivity搜索设备
if (mBluetoothSocket == null) {
Intent serveIntent = new Intent(getApplicationContext(), DevicesListActivity.class); //跳转活动
startActivityForResult(serveIntent, 1); //设置返回宏定义
} else {
//关闭连接socket
try {
bRun = false;
Thread.sleep(2000);
is.close();
mBluetoothSocket.close();
mBluetoothSocket = null;
connectButton.setText("连接");
} catch (InterruptedException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
}
});
//发送按钮响应
Button sendButton = (Button) findViewById(R.id.sendButton);
sendButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
int n = 0;
if (mBluetoothSocket == null) {
Toast.makeText(getApplicationContext(), "请先连接设备", Toast.LENGTH_SHORT).show();
return;
}
if (sendEditText.getText().length() == 0) {
Toast.makeText(getApplicationContext(), "请先输入数据", Toast.LENGTH_SHORT).show();
return;
}
try {
OutputStream os = mBluetoothSocket.getOutputStream(); //蓝牙连接输出流
byte[] bos = sendEditText.getText().toString().getBytes();
for (int i = 0; i < bos.length; i++) {
if (bos[i] == 0x0a) n++;
}
byte[] bos_new = new byte[bos.length + n];
n = 0;
for (int i = 0; i < bos.length; i++) { //手机中换行为0a,将其改为0d 0a后再发送
if (bos[i] == 0x0a) {
bos_new[n] = 0x0d;
n++;
bos_new[n] = 0x0a;
} else {
bos_new[n] = bos[i];
}
n++;
}
os.write(bos_new);
} catch (IOException e) {
e.printStackTrace();
}
}
});
// 设置设备可以被搜索
new Thread(){
public void run(){
if(mBluetoothAdapter.isEnabled()==false){
mBluetoothAdapter.enable();
}
}
}.start();
}
//接收活动结果，响应startActivityForResult()
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case 1: //连接结果，由DeviceListActivity设置返回
// 响应返回结果
if (resultCode == Activity.RESULT_OK) { //连接成功，由DeviceListActivity设置返回
// MAC地址，由DeviceListActivity设置返回
String address = data.getExtras().getString(DevicesListActivity.EXTRA_DEVICE_ADDRESS);
// 得到蓝牙设备句柄
mBluetoothDevice = mBluetoothAdapter.getRemoteDevice(address);
// 用服务号得到socket
try {
mBluetoothSocket = mBluetoothDevice.createRfcommSocketToServiceRecord(UUID.fromString(MY_UUID));
} catch (IOException e) {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
}
//连接socket
Button connectButton = findViewById(R.id.connectButton);
try {
mBluetoothSocket.connect();
Toast.makeText(this, "连接" + mBluetoothDevice.getName() + "成功！", Toast.LENGTH_SHORT).show();
connectButton.setText("断开");
} catch (IOException e) {
try {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
mBluetoothSocket.close();
mBluetoothSocket = null;
} catch (IOException ee) {
Toast.makeText(this, "连接失败！", Toast.LENGTH_SHORT).show();
}
return;
}
//打开接收线程
try {
is = mBluetoothSocket.getInputStream(); //得到蓝牙数据输入流
} catch (IOException e) {
Toast.makeText(this, "接收数据失败！", Toast.LENGTH_SHORT).show();
return;
}
if (bThread == false) {
readThread.start();
bThread = true;
} else {
bRun = true;
}
}
break;
default:
break;
}
}
//接收数据线程
Thread readThread=new Thread(){
public void run(){
int num = 0;
byte[] buffer = new byte[1024];
byte[] buffer_new = new byte[1024];
int i = 0;
int n = 0;
bRun = true;
//接收线程
while(true){
try{
while(is.available()==0){
while(bRun == false){}
}
while(true){
if(!bThread)//跳出循环
return;
num = is.read(buffer); //读入数据
n=0;
String s0 = new String(buffer,0,num);
for(i=0;i<num;i++){
if((buffer[i] == 0x0d)&&(buffer[i+1]==0x0a)){
buffer_new[n] = 0x0a;
i++;
}else{
buffer_new[n] = buffer[i];
}
n++;
}
String s = new String(buffer_new,0,n);
smsg+=s; //写入接收缓存
if(is.available()==0)break; //短时间没有数据才跳出进行显示
}
//发送显示消息，进行显示刷新
handler.sendMessage(handler.obtainMessage());
}catch(IOException e){
}
}
}
};
//消息处理队列
Handler handler= new Handler(){
public void handleMessage(Message msg){
super.handleMessage(msg);
tv_in.setText(smsg); //显示数据
scrollView.scrollTo(0,tv_in.getMeasuredHeight()); //跳至数据最后一页
}
};
//关闭程序掉用处理部分
public void onDestroy(){
super.onDestroy();
if(mBluetoothSocket!=null) //关闭连接socket
try{
mBluetoothSocket.close();
}catch(IOException e){}
// _bluetooth.disable(); //关闭蓝牙服务
}
}
Demo源码下载 https://download.csdn.net/download/qq_41121080/11954958
