我有以下代码与计算机上的C＃程序对话。当我在outputStream.write（bytes）代码之前添加断点时，它在我重新启动程序时工作正常。如果我只是让程序运行，它就不会发送消息。我认为这与时间有关，但我已经尝试了一切我能想到的，以确保BT在发送消息之前已连接。
点击按钮即发送消息。
以下是两个班级：
MainActivity.java
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
public static BluetoothAdapter mBluetoothAdapter;
public static BluetoothDevice mBluetoothDevice;
private String scannedContents;
private Button scanBtn;
private TextView formatTxt, contentTxt;
public static int mState = 0;
private ConnectThread btThread;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//Bottom Right Buttons
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(this);
//Setup BT
if (savedInstanceState == null) {
mBluetoothAdapter = ((BluetoothManager) getSystemService(Context.BLUETOOTH_SERVICE)).getAdapter();
if (mBluetoothAdapter != null) {
if (mBluetoothAdapter.isEnabled()) {
Set<BluetoothDevice> pairedDevices = mBluetoothAdapter.getBondedDevices();
if (pairedDevices.size() > 0) {
for (BluetoothDevice device : pairedDevices) {
if (device.getAddress().equalsIgnoreCase("00:1a:7d:da:71:11")) {
mBluetoothDevice = device;
ConnectThread btThread = new ConnectThread(mBluetoothDevice);
btThread.run();
}
}
} else
showErrorText(R.string.bt_not_paired);
} else {
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, Constants.REQUEST_ENABLE_BT);
}
} else {
showErrorText(R.string.bt_not_supported);
}
}
//Scanning Button Code
scanBtn = (Button) findViewById(R.id.scan_button);
formatTxt = (TextView) findViewById(R.id.scan_format);
contentTxt = (TextView) findViewById(R.id.scan_content);
scanBtn.setOnClickListener(this);
}
public void onClick(View v) {
//respond to clicks
if (v.getId() == R.id.scan_button) {
//scan
IntentIntegrator scanIntegrator = new IntentIntegrator(this);
scanIntegrator.initiateScan();
} else if (v.getId() == R.id.fab) {
btThread.write(scannedContents.getBytes());
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
switch (requestCode) {
case Constants.REQUEST_ENABLE_BT:
if (resultCode == RESULT_OK) {
//TODO
} else {
Toast.makeText(this, R.string.bt_not_enabled_leaving, Toast.LENGTH_SHORT).show();
finish();
}
case Constants.REQUEST_SCANNED_DATA:
//Scanner Code
IntentResult scanningResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
if (scanningResult.getContents() != null) {
//we have a result
String scanContent = scanningResult.getContents();
String scanFormat = scanningResult.getFormatName();
//TODO Do something with data
this.scannedContents = scanContent;
formatTxt.setText("FORMAT: " + scanFormat);
contentTxt.setText("CONTENT: " + scanContent);
} else {
Toast toast = Toast.makeText(getApplicationContext(), "No scan data received!", Toast.LENGTH_SHORT);
toast.show();
}
default:
super.onActivityResult(requestCode, resultCode, data);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@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();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
private void showErrorText(int messageId) {
TextView view = (TextView) findViewById(R.id.error_textview);
view.setText(getString(messageId));
}
public final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
//TODO
}
};
}
ConnectThread.java
public class ConnectThread extends Thread {
final BluetoothSocket mmSocket;
public ConnectThread(BluetoothDevice device) {
// Use a temporary object that is later assigned to mmSocket
// because mmSocket is final.
BluetoothSocket tmp = null;
try {
// Get a BluetoothSocket to connect with the given BluetoothDevice.
// MY_UUID is the app's UUID string, also used in the server code.
UUID uuid = UUID.fromString("F814E012-48FE-44F4-AF94-9D9C4CF7495A");
tmp = device.createRfcommSocketToServiceRecord(uuid);
} catch (IOException e) {
Log.e(TAG, "Socket's create() method failed", e);
}
mmSocket = tmp;
}
public void run() {
// Cancel discovery because it otherwise slows down the connection.
MainActivity.mBluetoothAdapter.cancelDiscovery();
try {
// Connect to the remote device through the socket. This call blocks
// until it succeeds or throws an exception.
mmSocket.connect();
} catch (IOException connectException) {
// Unable to connect; close the socket and return.
try {
mmSocket.close();
} catch (IOException closeException) {
Log.e(TAG, "Could not close the client socket", closeException);
}
return;
}
// The connection attempt succeeded. Perform work associated with
// the connection in a separate thread.
MainActivity.mState = 1;
}
public void write(byte[] bytes) {
try {
OutputStream outputStream = mmSocket.getOutputStream();
outputStream.write(bytes);
} catch (IOException e) {
e.printStackTrace();
}
}
// Closes the client socket and causes the thread to finish.
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "Could not close the client socket", e);
}
}
}
答案 0 :(得分：0)
确定。这是我不理解线程。问题是我使用的是thread.run（）而不是thread.start（）。