眾所周知藍芽是我們手機都有的一個功能
可以利用程式碼來實現管理藍芽的狀態

private BluetoothAdapter adapter;
    private BroadcastReceiver receiver = new BroadcastReceiver() {
        @Override
        public void onReceive(Context context, Intent intent) {
            //接收藍芽狀態變化的廣播
            String action = intent.getAction();
            //發現藍芽裝置
 

            BluetoothDevice device=intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
            if (action.equals(BluetoothDevice.ACTION_FOUND)) {
                String name=   device.getName();
            } else if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)) {
                //可以在監聽到藍芽狀態是進行操作
 

                switch (device.getBondState()){
                    case BluetoothDevice.BOND_BONDED:
                        //已經配對成功
                        break;
                    case BluetoothDevice.BOND_BONDING:
                        //正在連線
                        break;
                    case
 
 BluetoothDevice.BOND_NONE:
                        //取消連線
                        break;
                    default:
                        break;
                }
            }
        }
    };

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //藍芽連線裝置增加
        IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
        //藍芽連線狀態發生改變
        filter.addAction(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
        //註冊
        registerReceiver(receiver, filter);
        //獲取藍芽介面卡
        adapter  = BluetoothAdapter.getDefaultAdapter();
        boolean isenable = adapter.isEnabled();
        System.out.println(isenable + "<-=-=-=-isenable");
        //獲取藍芽是否可用
        Toast.makeText(MainActivity.this, isenable + "<-=-=-=-isenable", Toast.LENGTH_SHORT).show();
        if (!adapter.isEnabled()) {
            //開啟藍芽
            adapter.enable();
        } else {
            Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_DISCOVERABLE);
            //設定你自己的裝置可以被其他裝置搜尋的時間；最大3600
            intent.putExtra(BluetoothAdapter.EXTRA_DISCOVERABLE_DURATION, 300);
            startActivity(intent);
        }
        //藍芽裝置的地址
        String address = adapter.getAddress();
        String name = adapter.getName();
        Log.d("藍芽", "name=" + name + "  address=" + address);
        //獲取通過藍芽已經連線的裝置
        Set<BluetoothDevice> list = adapter.getBondedDevices();
        if (list != null) {
            for (BluetoothDevice device : list) {
                //裝置名稱
                String dname = device.getName();
            }
        }
        //搜尋其他裝置
        new Thread() {
            @Override
            public void run() {
                super.run();
                //正在搜尋狀態
                if (adapter.isDiscovering()) {
                    adapter.cancelDiscovery();
                }
                //開始搜尋其他裝置；
                adapter.startDiscovery();
            }
        }.start();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        unregisterReceiver(receiver);
    }