我一直在使用蓝牙设备并正在为它创建一个应用程序。
我应该可以通过发送代码0或1打开或关闭此设备LED。
我有一些错误赶上来帮助我解决这个问题，并且在盯着它多年后看不出问题出在哪里。
我正确找到设备，并检查了设备返回的MAC地址，这一切都很好。从我可以看到的日志我也似乎正确打开所有套接字。
在将字节数据发送到设备的过程的最后阶段发生错误。任何人都可以发现我无法做到的事情吗？也许连接没有成功？
澄清触发的异常是在sendData（）方法中。
如果你发现错误，我会永远爱你。
错误消息： Fatal Error, In onResume() and an exception occurred during write:socket closed.
那么套接字在数据发送之前关闭了什么，或者从未成功打开过什么？
无论如何，很多代码入站：
public class ScanFragment extends Fragment {
ArrayList<DeviceItem> scannedList;
Button scanningButton;
TextView scanningText;
ListView scannedListView;
BluetoothAdapter mBluetoothAdapter;
DeviceItem item;
DeviceCustomAdapter adapter;
BluetoothDevice device;
String TAG = "TEST";
private BluetoothAdapter btAdapter = null;
private BluetoothSocket btSocket = null;
private OutputStream outStream = null;
// Intent request codes
private static final int REQUEST_CONNECT_DEVICE_SECURE = 1;
private static final int REQUEST_ENABLE_BT = 3;
// Well known SPP UUID
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
// Insert your bluetooth devices MAC address
private static String address = "00:00:00:00:00:00";
public ScanFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_scan, container, false);
}
@Override
public void onDestroy() {
getActivity().unregisterReceiver(mReceiver);
super.onDestroy();
}
private final BroadcastReceiver mReceiver = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
Log.i("found", "hello" + "");
String action = intent.getAction();
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
device = intent
.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
item = new DeviceItem();
item.setDeviceName(device.getName());
item.setDeviceCode(device.getAddress());
item.setDeviceId(MY_UUID);
scannedList.add(item);
Log.i("BT", device.getName() + "\n" + device.getAddress());
} else {
Log.i("BT", "none" + "");
}
adapter = new DeviceCustomAdapter(
getActivity().getApplicationContext(), scannedList);
scannedListView.setAdapter(adapter);
}
};
@Override
public void onActivityCreated(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onActivityCreated(savedInstanceState);
super.onActivityCreated(savedInstanceState);
scannedList = new ArrayList<>();
scanningButton = (Button) getActivity().findViewById(R.id.scanningButton);
scanningText = (TextView) getActivity().findViewById(R.id.scanningText);
scannedListView = (ListView) getActivity().findViewById(R.id.scannedListView);
scannedListView.setVisibility(View.VISIBLE);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
if (Build.VERSION.SDK_INT >= 15 &&
ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.ACCESS_COARSE_LOCATION}, 1);
}
if (mBluetoothAdapter == null) {
scanningText.setText("Your device does not support Bluetooth, Sorry!");
} else if (!mBluetoothAdapter.isEnabled()) {
scanningText.setText("You need to enable bluetooth to use this app..");
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
}
scanningButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
scanningText.setText("Scanning...");
mBluetoothAdapter.startDiscovery();
mBluetoothAdapter.isDiscovering();
scanningText.setText("Click on a device to connect");
}
});
// Register for broadcasts when a device is discovered.
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
getActivity().registerReceiver(mReceiver, filter);
scannedListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
item = scannedList.get(position);
String name= scannedList.get(position).getDeviceName();
Toast toast = Toast.makeText(getActivity().getApplicationContext(), "Connecting to " + item.getDeviceCode() + "" + name, Toast.LENGTH_SHORT);
toast.show();
scanningText.setText(item.getDeviceCode());
mBluetoothAdapter.cancelDiscovery();
address = item.getDeviceCode();
// Create the result Intent and include the MAC address
connectDevice(address, true);
ledOff(view);
}
});
}
public void ledOn(View v){
sendData("1");
Toast msg = Toast.makeText(getActivity().getApplicationContext(), "LED is ON", Toast.LENGTH_SHORT);
msg.show();
}
public void ledOff(View v){
sendData("0");
Toast msg = Toast.makeText(getActivity().getApplicationContext(), "LED is OFF", Toast.LENGTH_SHORT);
msg.show();
}
public void connectToDevice(String adr) {
super.onResume();
//enable buttons once connection established.
// btnOn.setEnabled(true);
// btnOff.setEnabled(true);
// Set up a pointer to the remote node using it's address.
btAdapter = mBluetoothAdapter;
BluetoothDevice device = btAdapter.getRemoteDevice(adr);
// Two things are needed to make a connection:
// A MAC address, which we got above.
// A Service ID or UUID. In this case we are using the
// UUID for SPP.
try {
btSocket = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and socket create failed: " + e.getMessage() + ".");
}
// Discovery is resource intensive. Make sure it isn't going on
// when you attempt to connect and pass your message.
btAdapter.cancelDiscovery();
// Establish the connection. This will block until it connects.
try {
btSocket.connect();
} catch (IOException e) {
try {
btSocket.close();
} catch (IOException e2) {
errorExit("Fatal Error", "In onResume() and unable to close socket during connection failure" + e2.getMessage() + ".");
}
}
// Create a data stream so we can talk to server.
try {
outStream = btSocket.getOutputStream();
} catch (IOException e) {
errorExit("Fatal Error", "In onResume() and output stream creation failed:" + e.getMessage() + ".");
}
}
private void errorExit(String title, String message){
Toast msg = Toast.makeText(getActivity().getApplicationContext(), title + " - " + message, Toast.LENGTH_SHORT);
msg.show();
// finish();
}
private void sendData(String message) {
byte[] msgBuffer = message.getBytes();
try {
outStream.write(msgBuffer);
} catch (IOException e) {
String msg = "In onResume() and an exception occurred during write: " + e.getMessage();
errorExit("Fatal Error", msg);
}
}
private void connectDevice(String address, boolean secure) {
// Get the device MAC address
connectToDevice(address);
// Get the BluetoothDevice object
BluetoothDevice device = btAdapter.getRemoteDevice(address);
}
}