一、打开蓝牙权限 操作蓝牙之前必须先要注册蓝牙权限。在AndroidManifest.xml文件中注册权限：
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" ></uses-permission> <uses-permission android:name="android.permission.BLUETOOTH" ></uses-permission>二、动态申请蓝牙权限 某些android版本中蓝牙权限需要动态申请一次，调用下面的方法：
private void permission_request(){ ActivityCompat.requestPermissions(MainActivity.this, new String[]{ Manifest.permission.BLUETOOTH_ADMIN, Manifest.permission.BLUETOOTH}, 1); }申请结果会调用下面的回调函数：
@Override public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) { if (requestCode==1){ for (int i=0;i<grantResults.length;i++){ if (grantResults[i]!=0){ //权限成功 System.exit(0); } } } }三、蓝牙操作 蓝牙操作我直接封装了一个类，可以直接调用：
public class Bluetooth { private static final String TAG="Bluetooth"; private static BluetoothSocket mmSocket; private static BluetoothDevice mmDevice; private static final String SPP_UUID = "00001101-0000-1000-8000-00805F9B34FB"; private static InputStream mmInStream; private static OutputStream mmOutStream; public Bluetooth(BluetoothDevice device){ mmDevice = device; BluetoothSocket tmp = null; try { tmp = device.createRfcommSocketToServiceRecord(UUID .fromString(SPP_UUID)); } catch (IOException e) { Log.d(TAG, "create() failed", e); } mmSocket = tmp; new Thread(new Runnable() { @Override public void run() { // Make a connection to the BluetoothSocket try { // This is a blocking call and will only return on a // successful connection or an exception mmSocket.connect(); } catch (IOException e) { Log.e(TAG, "unable to connect() socket", e); // Close the socket try { mmSocket.close(); } catch (IOException e2) { } return; } InputStream tmpIn = null; OutputStream tmpOut = null; // Get the BluetoothSocket input and output streams try { tmpIn = mmSocket.getInputStream(); tmpOut = mmSocket.getOutputStream(); } catch (IOException e) { Log.e(TAG, "temp sockets not created", e); } mmInStream = tmpIn; mmOutStream = tmpOut; new Thread(new Runnable() { @Override public void run() { Log.i(TAG, "BEGIN mConnectedThread"); byte[] buffer = new byte[256*4]; int bytes; StringBuilder stringBuilder = new StringBuilder(); // Keep listening to the InputStream while connected while (true) { try { // Read from the InputStream if(mmInStream==null) break; bytes = mmInStream.read(buffer); String str = new String(buffer,0,bytes,"ascii"); Log.d("XP",str); } } catch (IOException e) { Log.e(TAG, "disconnected", e); break; }catch (RuntimeException e){ Log.e(TAG, "disconnected", e); break; } } } }).start(); } }).start(); } //蓝牙发送数据 public static void bluetooth_write_data(byte[] buffer) { try { if(mmOutStream!=null) mmOutStream.write(buffer); } catch (IOException e) { Log.e(TAG, "Exception during write", e); } } //判断蓝牙是否已经连接 public static Boolean bluetooth_is_connect(){ if (mmSocket!=null) return true; else return false; } //关闭连接 public static void bluetooth_close_connect() { try { if (mmSocket!=null){ mmSocket.close(); mmSocket=null; } if(mmInStream!=null){ mmInStream.close(); mmInStream=null; } if(mmOutStream!=null){ mmOutStream.close(); mmOutStream=null; } mmDevice=null; } catch (IOException e) { Log.e(TAG, "close() of connect socket failed", e); } } }四、蓝牙具体操作流程 1、首先判断蓝牙是否打开，如果没有打开就打开蓝牙
if (!mBluetoothAdapter.isEnabled()) { Intent enableIntent = new Intent( BluetoothAdapter.ACTION_REQUEST_ENABLE); startActivityForResult(enableIntent, REQUEST_ENABLE_BT); // Otherwise, setup the chat session }2.点击按钮开始扫描蓝牙设备
@Override public void onClick(View view) { // If we're already discovering, stop it if (mBtAdapter.isDiscovering()) { mBtAdapter.cancelDiscovery(); } // Request discover from BluetoothAdapter mBtAdapter.startDiscovery(); }3.注册一个监听器获取扫描设备结果
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND); myActivity.registerReceiver(mReceiver, filter); filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED); myActivity.registerReceiver(mReceiver, filter); private final BroadcastReceiver mReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { String action = intent.getAction(); if (BluetoothDevice.ACTION_FOUND.equals(action)) { BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE); ConnectShowInfo connectShowInfo = new ConnectShowInfo(); connectShowInfo.blueToothName=device.getName();//获取蓝牙名称 connectShowInfo.blueToothAddr=device.getAddress();//获取蓝牙地址 int rssi = intent.getExtras().getShort(BluetoothDevice.EXTRA_RSSI);//获取额外rssi值 connectShowInfo.singleStrength = rssi+"dB"; connectShowInfolist.add(connectShowInfo); connectListView.setAdapter(connectShowInfoAdapter); // When discovery is finished, change the Activity title } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) { } } };4.点击扫描到的设备开始连接
mBtAdapter.cancelDiscovery();//取消扫描 address = connectShowInfolist.get(i).blueToothAddr; //获取点击的地址 test.get_connect_address(address);//开始连接 public void get_connect_address(String addr) { BluetoothDevice device = mBluetoothAdapter.getRemoteDevice(addr); if(bluetooth.bluetooth_is_connect()) { //蓝牙已经连接 bluetooth.bluetooth_close_connect(); bluetooth=null; } if(bluetooth==null) bluetooth = new Bluetooth(device);//调用前面那个类开始连接 }