小编Bha*_*ula的帖子

我在Android应用程序中创建了一个蓝牙活动类,它适用于所有蓝牙功能,如:扫描,配对,连接,发送和接收数据.

真正的问题是当Activity被销毁时.蓝牙正在断开连接.

如何在整个应用程序中建立蓝牙连接.我想从其他活动向蓝牙发送数据.

帮助我以简单的方式实现这一点？

public class BTActivity extends AppCompatActivity {

ArrayList<BluetoothDevice> devices = new ArrayList<>();
BluetoothAdapter mBluetoothAdapter;
BluetoothDevice mBluetoothDevice;
ArrayAdapter<BluetoothDevice> arrayAdapter;

ConnectThread c;

private static final String TAG = "MY_BT";

ListView lvPaired;
Button BluetoothOnOff, ScanBt, pairedlist, sendButton, btDisconnect, incrementBtn, decrementBtn;
EditText input_text;
TextView ConnectedTo;

FragmentManager fm = getSupportFragmentManager();

UUID BHANU_UUID = UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_bt);

    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    lvPaired = findViewById(R.id.btPairedLV);
    pairedlist = findViewById(R.id.btPaired);
    input_text = findViewById(R.id.user_input);
    sendButton = findViewById(R.id.btnSend);
    BluetoothOnOff = findViewById(R.id.offOn_bt);
    ScanBt = …

我尝试并遵循了一些网络教程，但它不适用于新的 Android 版本。

我声明了所有蓝牙权限并使用了 Dexter 权限库。我遵循了几个答案，但它也没有显示可用的蓝牙设备名称

下面是我的代码：

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
    scan.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            toast("starts scanning...");
            mBluetoothAdapter.startDiscovery();

        }
    });

    mAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1);
    mListView.setAdapter(mAdapter);

    mListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
           String bluetoothDevice = mAdapter.getItem(i);
           toast(bluetoothDevice);
        }
    });

}
public void pairedDevicesListView(View view){
    mAdapter.clear();

    pairedDevices = mBluetoothAdapter.getBondedDevices();

    for (BluetoothDevice device : pairedDevices){
        mAdapter.add(device.getName() + "\n" + device.getAddress());

    }
} …