多活动蓝牙

Question

我正在尝试蓝牙一些活动。

（DeviceList.java和LedControl.java的来源：https://github.com/danz1ka19/Android-App-HC05-Arduino/tree/master/app/src/main/java/com/example/danyal/bluetoothhc05）

这是我的代码：

DeviceList.java

public class DeviceList extends AppCompatActivity {

Button btnPaired;
ListView devicelist;

private BluetoothAdapter myBluetooth = null;
private Set<BluetoothDevice> pairedDevices;
public static String EXTRA_ADDRESS = "device_address";

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

    btnPaired = (Button) findViewById(R.id.button);
    devicelist = (ListView) findViewById(R.id.listView);

    myBluetooth = BluetoothAdapter.getDefaultAdapter();
    if ( myBluetooth==null ) {
        Toast.makeText(getApplicationContext(), "Bluetooth device not available", Toast.LENGTH_LONG).show();
        finish();
    } else if ( !myBluetooth.isEnabled() ) {
        Intent turnBTon = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(turnBTon, 1);
    }

    btnPaired.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            pairedDevicesList();
        }
    });
}

private void pairedDevicesList () {
    pairedDevices = myBluetooth.getBondedDevices();
    ArrayList list = new ArrayList();

    if ( pairedDevices.size() > 0 ) {
        for ( BluetoothDevice bt : pairedDevices ) {
            list.add(bt.getName().toString() + "\n" + bt.getAddress().toString());
        }
    } else {
        Toast.makeText(getApplicationContext(), "No Paired Bluetooth Devices Found.", Toast.LENGTH_LONG).show();
    }

    final ArrayAdapter adapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, list);
    devicelist.setAdapter(adapter);
    devicelist.setOnItemClickListener(myListClickListener);
}

private AdapterView.OnItemClickListener myListClickListener = new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
        String info = ((TextView) view).getText().toString();
        String address = info.substring(info.length()-17);

        Intent i = new Intent(DeviceList.this, ledControl.class);
        i.putExtra(EXTRA_ADDRESS, address);
        startActivity(i);
    }
};

LedControl.java

public class ledControl extends AppCompatActivity {

Button btn1, btn2, btn3, btn4, btn5, btnDis;
String address = null;
TextView lumn;
private ProgressDialog progress;
BluetoothAdapter myBluetooth = null;
BluetoothSocket btSocket = null;
private boolean isBtConnected = false;
static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Intent newint = getIntent();
    address = newint.getStringExtra(DeviceList.EXTRA_ADDRESS);

    setContentView(R.layout.activity_led_control);

    btn1 = (Button) findViewById(R.id.button2);
    btn2 = (Button) findViewById(R.id.button3);
    btn3 = (Button) findViewById(R.id.button5);
    btn4 = (Button) findViewById(R.id.button6);
    btn5 = (Button) findViewById(R.id.button7);
    btnDis = (Button) findViewById(R.id.button4);
    lumn = (TextView) findViewById(R.id.textView2);

    new ConnectBT().execute();


    btn1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent i = new Intent(ledControl.this, test.class);
            i.putExtra(DeviceList.EXTRA_ADDRESS, address);
            startActivity(i);
        }
    });

}

private void sendSignal ( String number ) {
    if ( btSocket != null ) {
        try {
            btSocket.getOutputStream().write(number.toString().getBytes());
        } catch (IOException e) {
            msg("Error");
        }
    }
}

private void Disconnect () {
    if ( btSocket!=null ) {
        try {
            btSocket.close();
        } catch(IOException e) {
            msg("Error");
        }
    }

    finish();
}

private void msg (String s) {
    Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show();
}

private class ConnectBT extends AsyncTask<Void, Void, Void> {
    private boolean ConnectSuccess = true;

    @Override
    protected  void onPreExecute () {
        progress = ProgressDialog.show(ledControl.this, "Connecting...", "Please Wait!!!");
    }

    @Override
    protected Void doInBackground (Void... devices) {
        try {
            if ( btSocket==null || !isBtConnected ) {
                myBluetooth = BluetoothAdapter.getDefaultAdapter();
                BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address);
                btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID);
                BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
                btSocket.connect();
            }
        } catch (IOException e) {
            ConnectSuccess = false;
        }

        return null;
    }

    @Override
    protected void onPostExecute (Void result) {
        super.onPostExecute(result);

        if (!ConnectSuccess) {
            msg("Connection Failed. Is it a SPP Bluetooth? Try again.");
            finish();
        } else {
            msg("Connected");
            isBtConnected = true;
        }

        progress.dismiss();
    }
}}

到目前为止，太好了。作为一个初学者，我试图使蓝牙在一项新的活动中发挥作用。但是当我进入这个test.java活动时。我回到第一个活动“ DeviseList.java”（或崩溃应用程序）。

Test.java

public class test extends AppCompatActivity {

String address = null;
private ProgressDialog progress;
BluetoothAdapter myBluetooth = null;
BluetoothSocket btSocket = null;
private boolean isBtConnected = false;
static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");


private TextView connect;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);


    Intent newint = getIntent();
    address = newint.getStringExtra(DeviceList.EXTRA_ADDRESS);
    setContentView(R.layout.activity_test);




    connect = (TextView) findViewById(R.id.textView4);
    new ConnectBT().execute();


}




private void msg (String s) {
    Toast.makeText(getApplicationContext(), s, Toast.LENGTH_LONG).show();
}

private class ConnectBT extends AsyncTask<Void, Void, Void> {
    private boolean ConnectSuccess = true;



    @Override
    protected Void doInBackground (Void... devices) {
        try {
            if ( btSocket==null || !isBtConnected ) {
                myBluetooth = BluetoothAdapter.getDefaultAdapter();
                BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address);
                btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID);
                BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
                btSocket.connect();
            }
        } catch (IOException e) {
            ConnectSuccess = false;
        }

        return null;
    }
    @Override
    protected void onPostExecute (Void result) {
        super.onPostExecute(result);

        if (!ConnectSuccess) {
            msg("Connection Failed. Is it a SPP Bluetooth? Try again.");
            finish();
        } else {
            msg("Connected");
            isBtConnected = true;
        }

        progress.dismiss();
    }

}}

谢谢您的帮助。