Android 滞后/不稳定的蓝牙连接

Android lagging / instable bluetooth connection

我在使用不安全的 RFCOMM 连接连接到 WML-C46 AH 蓝牙芯片时遇到问题。我编写了一个只有相关代码的 android 应用程序来向您展示我的问题。

应用程序

该应用程序只有一个按钮。如果单击此按钮，则会启动蓝牙设备发现。发现完成后，应用程序连接到蓝牙设备(我只使用一个蓝牙设备进行测试，因此找不到任何其他设备)。然后它打开一个输入流来读取这个设备的数据。如果连接中断(抛出 ioexception)或再次单击按钮，则关闭连接(关闭所有线程、套接字和流)。如果您再次单击该按钮，则会启动新设备发现，依此类推…

问题

连接不正常。数据输入流似乎有点滞后，有时连接中断而没有任何明显的原因(IOException：软件导致连接中止或 IOException：再试一次)。它几乎是 android 蓝牙聊天示例的简化版本，它使用设备发现而不是配对设备和一个活动。

密码

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public class MainActivity extends Activity implements View.OnClickListener {

BluetoothDevice btDevice;
BluetoothSocket btSocket;
InputStream inStream;
OutputStream outStream;
Object lock = new Object();
boolean connected = false;
boolean canceled = false;

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

Button btn = (Button) findViewById(R.id.button1);
btn.setOnClickListener(this);

IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_FOUND);
getApplicationContext().registerReceiver(btReceiver, filter);
filter = new IntentFilter(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
getApplicationContext().registerReceiver(btReceiver, filter);
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}

@Override
public void onClick(View arg0) {
if (!connected) {
connected = true;
canceled = false;

new Thread(new Runnable() {
@Override
public void run() {
BluetoothAdapter btAdapter = BluetoothAdapter
.getDefaultAdapter();

try {
if (btAdapter.isDiscovering())
btAdapter.cancelDiscovery();
btAdapter.startDiscovery();

// block until device discovery has finished
synchronized (lock) {
try {
lock.wait();
} catch (InterruptedException e) {
Log.d("EXCEPTION","", e);
}
}

btSocket = btDevice.createInsecureRfcommSocketToServiceRecord(UUID
.fromString("00001101-0000-1000-8000-00805F9B34FB"));
btSocket.connect();

inStream = btSocket.getInputStream();
outStream = btSocket.getOutputStream();

new Thread(new Runnable() {
@Override
public void run() {
while (!canceled) {
try {
int in;
while ((in = inStream.read()) != -1) {
Log.d("Received new byte:", in
+"");
}
} catch (IOException e) {
Log.d("EXCEPTION IN LISTENER","", e);
disconnect();
}
}
}
}).start();
} catch (IOException e) {
Log.d("","", e);
}
}
}).start();
} else {
disconnect();
}
}

private void disconnect() {
connected = false;
canceled = true;

try {
btSocket.close();
} catch (Exception e) {
Log.d("EXCEPTION DISCONNECTING","", e);
}
try {
inStream.close();
} catch (Exception e) {
Log.d("EXCEPTION DISCONNECTING","", e);
}
try {
outStream.close();
} catch (Exception e) {
Log.d("EXCEPTION DISCONNECTING","", e);
}

btDevice = null;
btSocket = null;
inStream = null;
outStream = null;
}

private final BroadcastReceiver btReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent) {
String action = intent.getAction();
try {
if (BluetoothDevice.ACTION_FOUND.equals(action)) {
btDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
} else if (BluetoothAdapter.ACTION_DISCOVERY_FINISHED.equals(action)) {
synchronized (lock) {
lock.notifyAll();
}
}
} catch (Exception e) {
Log.d(this.getClass().getName(),"", e);
}
}
};
}

我只是使用阻塞方法或自己进行阻塞。因此，连接建立工作非常程序化。当我调整它时，我可能已经丢失了 android 示例的连接流程，但我找不到问题。

输出

建立连接：

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01-16 16:52:46.234: V/BluetoothSocket.cpp(6961): initSocketNative
01-16 16:52:46.234: V/BluetoothSocket.cpp(6961): …fd 47 created (RFCOMM, lm = 0)
01-16 16:52:46.234: V/BluetoothSocket.cpp(6961): initSocketFromFdNative
01-16 16:52:46.257: D/BluetoothUtils(6961): isSocketAllowedBySecurityPolicy start : device null
01-16 16:52:47.171: V/BluetoothSocket.cpp(6961): connectNative
01-16 16:52:47.570: V/BluetoothSocket.cpp(6961): …connect(47, RFCOMM) = 0 (errno 115)

连接中断：

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01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): java.io.IOException: Software caused connection abort
01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): at android.bluetooth.BluetoothSocket.readNative(Native Method)
01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:388)
01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:60)
01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): at com.example.bttest.MainActivity$2$1.run(MainActivity.java:100)
01-16 16:53:38.539: D/EXCEPTION IN LISTENER(6961): at java.lang.Thread.run(Thread.java:856)

谢谢！

发现问题。蓝牙设备未按预期工作，并在几秒钟后关闭连接。然而，代码工作得很好。

原创文章，作者：ItWorker，如若转载，请注明出处：https://blog.ytso.com/269014.html

Android 滞后/不稳定的蓝牙连接

Android lagging / instable bluetooth connection

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