android 蓝牙连接多长时间,Android蓝牙套接字连接耗时太长,最终失败

我正在尝试从Android手机连接蓝牙设备.在大多数情况下,连接成功.我使用以下代码进行套接字连接:

if (isUsingHtcTypeConnectionScheme) {

try {

if (LOG_ENABLED) Log.d(TAG,"connecting to SPP with createRfcommSocket");

Method m = mRemoteDevice.getClass().getMethod("createRfcommSocket", new Class[] { int.class });

tmpSocket = (BluetoothSocket)m.invoke(mRemoteDevice, 1); // may be from 1 to 3

} catch (java.lang.NoSuchMethodException e){

Log.e(TAG, "java.lang.NoSuchMethodException!!!", e);

} catch ( java.lang.IllegalAccessException e ){

Log.e(TAG, "java.lang.IllegalAccessException!!!", e);

} catch ( java.lang.reflect.InvocationTargetException e ){

Log.e(TAG, "java.lang.InvocationTargetException!!!", e);

}

}

if (tmpSocket == null) {

try {

if (LOG_ENABLED) Log.d(TAG,"connecting to SPP with createRfcommSocketToServiceRecord");

tmpSocket = mRemoteDevice.createRfcommSocketToServiceRecord(uuid); // Get a BluetoothSocket for a connection with the given BluetoothDevice

} catch (IOException e) {

Log.e(TAG, "socket create failed", e);

}

}

mBtSocket = tmpSocket;

try {

mBtSocket.connect();

} catch (IOException e) {

connectionFailed();

setState(STATE_IDLE);

return;

}

如果其他设备的蓝牙未打开,它将在2-3秒内抛出IOException,这是正常行为.

但有时连接需要20-30秒并最终失败,而其他设备的蓝牙功能已打开.

我想知道为什么会发生这种情况,如果手机无法连接到设备,它应该在2-3秒内抛出IOException.但现在需要20-30秒才能抛出IOException.(其他设备已准备好连接)

我在几部Android手机上测试过也有这个问题,所以可能与特定手机无关.

有任何想法吗？谢谢!