java - 如何通过蓝牙从两个不同的 Activity 传输数据？

我试图将数据从我的应用程序发送到我的Arduino板上以制作led灯。
问题是，如果我从主要活动发送该消息，但从另一个活动（HolopickerColor）发送该消息，则它不起作用，并且没有收到任何错误。
谢谢你的回答。

MainActivity：

public class MainActivity extends AppCompatActivity{
private Button mPairedBtn;
Button on, find;
public BluetoothAdapter BA;
private ProgressDialog mProgressDlg;
// public ConnectedThread mConnectedThread;
private ArrayList<BluetoothDevice> mDeviceList = new ArrayList<BluetoothDevice>();
private DrawerLayout mDrawerLayout;

private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
Button btnOn, btnOff;
// SPP UUID service
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

// MAC-address of Bluetooth module (you must edit this line)
private static String address ;

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

    setContentView(R.layout.activity_main);

    on = (Button) findViewById(R.id.btn_enable);

    find = (Button) findViewById(R.id.btn_scan);
    mPairedBtn = (Button) findViewById(R.id.btn_view_paired);


    BA = BluetoothAdapter.getDefaultAdapter();
    mProgressDlg = new ProgressDialog(this);


    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    ActionBar actionBar = getSupportActionBar();
    actionBar.setHomeAsUpIndicator(R.drawable.ic_menu);
    actionBar.setDisplayHomeAsUpEnabled(true);

    mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);

    NavigationView navigationView = (NavigationView) findViewById(R.id.navigation_view);
    navigationView.setNavigationItemSelectedListener(new NavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(MenuItem menuItem) {
            menuItem.setChecked(true);
            mDrawerLayout.closeDrawers();
            Toast.makeText(MainActivity.this, menuItem.getTitle(), Toast.LENGTH_LONG).show();
            switch (menuItem.getItemId()) {
                case R.id.nav_item_colorlight:
                    Intent color = new Intent(MainActivity.this, HolopickerColor.class);
                   // color.putExtra("color", ConnectedThread.getInstance());
                    startActivity(color);
                    break;
                case R.id.nav_item_effectlight:
                    Intent light = new Intent(MainActivity.this, LightEffect.class);
                    startActivity(light);
                    break;
                case R.id.nav_item_music:
                    Intent music = new Intent(MainActivity.this, Music.class);
                    startActivity(music);
                    break;
                case R.id.nav_item_about:
                    Intent about = new Intent(MainActivity.this, About.class);
                    startActivity(about);
                    break;
            }

            return true;
        }
    });

    mProgressDlg.setMessage("Scanning...");
    mProgressDlg.setCancelable(false);
    mProgressDlg.setButton(DialogInterface.BUTTON_NEGATIVE, "Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();

            BA.cancelDiscovery();
        }
    });

    if (BA == null) {
        showUnsupported();
    } else {
        mPairedBtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Set<BluetoothDevice> pairedDevices = BA.getBondedDevices();

                if (pairedDevices == null || pairedDevices.size() == 0) {
                    showToast("No Paired Devices Found");
                } else {
                    ArrayList<BluetoothDevice> list = new ArrayList<BluetoothDevice>();

                    list.addAll(pairedDevices);

                    Intent intent = new Intent(MainActivity.this, DeviceListActivity.class);

                    intent.putParcelableArrayListExtra("device.list", list);

                    startActivity(intent);
                }
            }
        });

        find.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View arg0) {
                BA.startDiscovery();
            }
        });

        on.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (BA.isEnabled()) {
                    BA.disable();

                    showDisabled();
                    try
                    {
                        btSocket.close();
                    } catch (IOException e2)
                    {
                        //insert code to deal with this
                    }

                } else {
                    Intent intent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);

                    startActivityForResult(intent, 1000);
                }
            }
        });

        if (BA.isEnabled()) {
            showEnabled();
        } else {
            showDisabled();
        }
    }
    IntentFilter filter = new IntentFilter();

    filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);
    filter.addAction(BluetoothDevice.ACTION_FOUND);
    filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
    filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);



    registerReceiver(mReceiver, filter);

    btnOn = (Button) findViewById(R.id.btnOn);
    btnOff = (Button) findViewById(R.id.btnOff);


    // Set up onClick listeners for buttons to send 1 or 0 to turn on/off LED
    btnOff.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
           /* r = 255;
            g = 15;
            b = 50;


            mConnectedThread.write("r"+Integer.toString(r)+"\n");    // Send "0" via Bluetooth
            mConnectedThread.write("g"+Integer.toString(g)+"\n");
            mConnectedThread.write("b"+Integer.toString(b)+"\n");*/
            ConnectedThread.getInstance().write("1");
            Toast.makeText(getBaseContext(), "Turn off LED", Toast.LENGTH_SHORT).show();
        }
    });

    btnOn.setOnClickListener(new OnClickListener() {
        public void onClick(View v) {
            //cathode nen 1 la off, o la on
            ConnectedThread.getInstance().write("0");    // Send "1" via Bluetooth //gui nhan ne
            Toast.makeText(getBaseContext(), "Turn on LED", Toast.LENGTH_SHORT).show();
        }
    });

    //Get MAC address from DeviceListActivity via intent
    //   Intent intent = getIntent();

    //Get the MAC address from the DeviceListActivty via EXTRA
    //address = intent.getStringExtra(DeviceListActivity.EXTRA_DEVICE_ADDRESS);

    // MAC-address of Bluetooth module (you must edit this line)
    address = "30:14:10:09:07:86";

    //create device and set the MAC address
    BluetoothDevice device = BA.getRemoteDevice(address);

    try {
        btSocket = createBluetoothSocket(device);
    } catch (IOException e) {
        Toast.makeText(getBaseContext(), "Socket creation failed", Toast.LENGTH_LONG).show();
    }
    // Establish the Bluetooth socket connection.
    try
    {
        btSocket.connect();
    } catch (IOException e) {
        try
        {
            btSocket.close();
        } catch (IOException e2)
        {
            //insert code to deal with this
        }
    }

    ConnectedThread.createInstance(btSocket);
    ConnectedThread.getInstance().start();
    //I send a character when resuming.beginning transmission to check device is connected
    //If it is not an exception will be thrown in the write method and finish() will be called

}



private BluetoothSocket createBluetoothSocket(BluetoothDevice device) throws IOException {

    return  device.createRfcommSocketToServiceRecord(MY_UUID);
    //creates secure outgoing connecetion with BT device using UUID
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    switch (id) {
        case android.R.id.home:
            mDrawerLayout.openDrawer(GravityCompat.START);
            return true;
    }

    return super.onOptionsItemSelected(item);
}

public void onPause() {
    if (BA != null) {
        if (BA.isDiscovering()) {
            BA.cancelDiscovery();
        }
    }

    try
    {
        //Don't leave Bluetooth sockets open when leaving activity
        btSocket.close();
    } catch (IOException e2) {
        //insert code to deal with this
    }
    super.onPause();

}

@Override
public void onDestroy() {
    unregisterReceiver(mReceiver);

    super.onDestroy();
}

private void showEnabled() {
    Toast.makeText(getApplicationContext(), "on", Toast.LENGTH_LONG).show();
    on.setText("Disable");
    on.setEnabled(true);

    mPairedBtn.setEnabled(true);
    find.setEnabled(true);
}

private void showDisabled() {
    Toast.makeText(getApplicationContext(), "off", Toast.LENGTH_LONG).show();
    on.setText("Enable");
    on.setEnabled(true);

    mPairedBtn.setEnabled(false);
    find.setEnabled(false);
}

private void showUnsupported() {
    Toast.makeText(getApplicationContext(), "Bluetooth is unsupported by this device", Toast.LENGTH_LONG).show();

    on.setText("Enable");
    on.setEnabled(false);

    mPairedBtn.setEnabled(false);
    find.setEnabled(false);
}

private void showToast(String message) {
    Toast.makeText(getApplicationContext(), message, Toast.LENGTH_SHORT).show();
}

private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();

        if (BluetoothAdapter.ACTION_STATE_CHANGED.equals(action)) {
            final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, BluetoothAdapter.ERROR);

            if (state == BluetoothAdapter.STATE_ON) {
                showToast("Enabled");

                showEnabled();
            }
        } else if (BluetoothAdapter.ACTION_DISCOVERY_STARTED.equals(action)) {
            mDeviceList = new ArrayList<BluetoothDevice>();

            mProgressDlg.show();
        } else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
            mProgressDlg.dismiss();

            Intent newIntent = new Intent(MainActivity.this, DeviceListActivity.class);

            newIntent.putParcelableArrayListExtra("device.list", mDeviceList);

            startActivity(newIntent);
        } else if (BluetoothDevice.ACTION_FOUND.equals(action)) {
            BluetoothDevice device = (BluetoothDevice) intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);

            mDeviceList.add(device);

            showToast("Found device " + device.getName());
        }
    }
};

第二项活动：

public class HolopickerColor extends AppCompatActivity implements ColorPicker.OnColorChangedListener {
private TextView text;
com.larswerkman.holocolorpicker.ColorPicker picker;
SVBar svBar ;
Button test;



@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_holopicker_color);
    picker = (ColorPicker) findViewById(R.id.picker);
    svBar = (SVBar) findViewById(R.id.svbar);

    text = (TextView) findViewById(R.id.color1);

    picker.addSVBar(svBar);

    picker.getColor();

    picker.setOnColorChangedListener(this);

    picker.setShowOldCenterColor(false);// Tat mau cu
    test = (Button)findViewById(R.id.test);
    test.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {

            ConnectedThread.getInstance().write("r255\n");
            Toast.makeText(getBaseContext(),"yes",Toast.LENGTH_LONG).show();
        }
    });
    //ConnectedThread.getInstance().start();
}


public void onColorChanged(int color) {
    // TODO Auto-generated method stub
    text.setTextColor(color);//hien mau len chu
    if (ConnectedThread.getInstance() != null) {
        int r = (color >> 16) & 0xFF;//xuat kieu mau ra thanh chu
        int g = (color >> 8) & 0xFF;
        int b = (color >> 0) & 0xFF;

        // mTcpClient.sendMessage(Integer.toHexString(picker.getColor()));

        ConnectedThread.getInstance().write("r255");//gui ko nhan ne

这是ConnectedThread：

class ConnectedThread extends Thread {
    private final BluetoothSocket mmSocket;
    private final OutputStream mmOutStream; // cai nay e can implement Serializable nua
    private static ConnectedThread instance = null;

    private ConnectedThread(BluetoothSocket socket) {
        mmSocket = socket;
        OutputStream tmpOut = null;

        // Get the input and output streams, using temp objects because
        // member streams are final
        try {
            tmpOut = socket.getOutputStream();
        } catch (IOException e) { }

        mmOutStream = tmpOut;
    }

    public static void createInstance(BluetoothSocket socket) {
        if (instance == null) {
            instance = new ConnectedThread(socket);
        }
    }

    public static ConnectedThread getInstance() {
        return instance;
    }

    //write method
    public void write(String input) {
        byte[] msgBuffer = input.getBytes();           //converts entered String into bytes
        try {
            mmOutStream.write(msgBuffer);                //write bytes over BT connection via outstream
        } catch (IOException e) {
            cancel();

        }
    }

    /* Call this from the main activity to shutdown the connection */
    public void cancel() {
        try {
            mmSocket.close();
        } catch (IOException e) { }
    }
}

最佳答案

问题是您正在使用ConnectedThread创建BluetoothSocket单例实例，然后在活动的onPause方法中关闭同一套接字。因此，基本上，在调用onPause之后，ConnectedThread实例将不再发送任何内容。取而代之的是，您应该管理ConnectedThread套接字，即保留对其的引用，然后在不再需要它或检测到问题时将其关闭。

顺便说一句，关闭套接字后，每次在write上调用ConnectedThread时，都会调用cancel方法。如果您不使用这种方法沉默异常，则将能够轻松检测到问题。这就是为什么您永远不应该有一个空的catch块的原因。