android不连接蓝牙设备管理器,2个Android蓝牙无法连接的原因和解决方法

错误为&＃xff1a; RFCOMM_CreateConnection - already opened state:2, RFC state:4, MCB state:5

原因&＃xff1a;socket没有关闭。即使使用了代码socket.close().但是硬件需要时间反应。

解决方法&＃xff1a;在socket.close();添加       SystemClock.sleep(POST_RESET_DELAY);等待关闭socket。POST_RESET_DELAY的值可设置为1000&＃xff0c;也就是1秒。一秒应当足够了。

另外有时候蓝牙还是无法连接&＃xff0c;说socket为空&＃xff0c;代码如下&＃xff1a;

if(mSocket&＃61;&＃61;null) {

BluetoothCon.this.start();

return;

}

//Sleep time of 1000ms after closing the socket

SystemClock.sleep(POST_RESET_DELAY);

mSocket.connect();//有一次执行connect的时候 &＃xff0c;显示没有源码。mSocket为null。虽然前面判断了mSocket&＃61;&＃61;null

原因是是使用SystemClock.sleep(POST_RESET_DELAY);之前socket不为空&＃xff0c;但是之后由于线程问题&＃xff0c;socket为空。

所以使用socket之前要先判断下socket是否为空&＃xff0c;如果为空就重新连接。

下面是修改后的代码&＃xff1a;

//Sleep time of 1000ms after closing the socket

SystemClock.sleep(POST_RESET_DELAY);

if(mSocket!&＃61;null) {

mSocket.connect();

}

else

{

BluetoothCon.this.start();//BluetoothCon中有代码重新为socket赋值

return;

}

另api level 14有函数isConnected()可以判断是否已经连接。

参考资料&＃xff1a;

http://stackoverflow.com/questions/7888294/rfcomm-createconnection-already-opened-state2-rfc-state4-mcb-state5?lq&＃61;1

Solution

Starting from API Level 14 there is a Method in BluetoothSocket called isConected(), which returns true, if this socket is already connected and false otherwise, here the original excerpt from the API:

Get the connection status of this socket, ie, whether there is an active connection with remote device.

For API levels <14 you can work around this issue by putting your Bluetooth Handling Thread to sleep after closing the connection - 1000 ms should be enough, here is an example (btDevice is of the type BluetoothDevice and has been initialized prior to the code snippet below):

try{//Open the socket to an SPP device (UUID taken from Android API for createRfcommSocketToServiceRecord)BluetoothSocketbtSocket&＃61;btDevice.createRfcommSocketToServiceRecord("00001101-0000-1000-8000-00805F9B34FB");//Connect to the socketbtSocket.connect();//Close the socketbtSocket.close();//Sleep time of 1000ms after closing the socketSystemClock.sleep(POST_RESET_DELAY);}catch(Throwablee){// Log error message}