android 蓝牙BluetoothAdapter扫描、获蓝牙设备、已联设备列表

效果：

public class MainActivity extends AppCompatActivity {
    private static final String TAG="MainActivity";
    private List list;
    private RecyclerView recyclerView;
    private MyRecycleViewAdapter adapter;
    private Button btn;
    BluetoothAdapter btAdapt;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        initData();
    }

    private void initView() {
        list=new ArrayList<>();
        recyclerView=findViewById(R.id.main_device_listview);
        btn=findViewById(R.id.main_btn_start);
        adapter=new MyRecycleViewAdapter(this,list);
        recyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(adapter);
    }

    private void initData() {
        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (btAdapt.getState() != BluetoothAdapter.STATE_ON) {// 如果蓝牙还没开启
                    Toast.makeText(getBaseContext(), "请先开启蓝牙", Toast.LENGTH_SHORT).show();
                    return;
                }

                if (!btAdapt.isDiscovering()) {
                    list.clear();
                    addPairedDevice();
                    btAdapt.startDiscovery();
                }
            }
        });

        btAdapt = BluetoothAdapter.getDefaultAdapter();
        if (btAdapt == null) {
            Toast.makeText(getBaseContext(), "您的机器上没有发现蓝牙适配器，本程序将不能运行!", Toast.LENGTH_SHORT).show();
            this.finish();
        }

        // 注册Receiver来获取蓝牙设备相关的结果
        IntentFilter intent = new IntentFilter();
        intent.addAction(BluetoothDevice.ACTION_FOUND); // 用BroadcastReceiver来取得搜索结果
        intent.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
        intent.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(searchDevices, intent);

        addPairedDevice();
    }
    private BroadcastReceiver searchDevices = new BroadcastReceiver() {

        public void onReceive(Context context, Intent intent) {
            String action = intent.getAction();

            if (action.equals(BluetoothDevice.ACTION_FOUND)) { //found device
                BluetoothDevice device = intent
                        .getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
                String str = device.getName() + "|" + device.getAddress();

                Log.e(TAG, "onReceive str: "+str );
                if (list.indexOf(str) == -1)// 防止重复添加
                    list.add(str); // 获取设备名称和mac地址
                adapter.UpdataList(list);

            } else if (action.equals(BluetoothAdapter.ACTION_DISCOVERY_STARTED)) {
                Toast.makeText(getBaseContext(), "正在扫描", Toast.LENGTH_SHORT).show();
                btn.setText("正在扫描");
                btn.setTextColor(Color.RED);
            } else if (action
                    .equals(BluetoothAdapter.ACTION_DISCOVERY_FINISHED)) {
                btn.setText("扫描设备");
                btn.setTextColor(Color.BLACK);
                Toast.makeText(getBaseContext(), "扫描完成，点击列表中的设备来尝试连接", Toast.LENGTH_SHORT).show();
            }
        }
    };
    // 增加配对设备
    private void addPairedDevice() {
        Set pairedDevices = btAdapt.getBondedDevices();
        if (pairedDevices.size() > 0) {
            for (BluetoothDevice device : pairedDevices) {
                String str = device.getName() + "|" + device.getAddress();
                list.add(str);
                adapter.notifyDataSetChanged();
            }
        }
    }


    @Override
    protected void onDestroy() {
        super.onDestroy();
        android.os.Process.killProcess(android.os.Process.myPid());
    }
}