连接到蓝牙设备发生故障时的深度睡眠 [英] Connecting to Bluetooth device fails in deep sleep

问题描述

我试图连接到已配对的蓝牙装置每25秒，通过AlarmManager计划，触发一个WakefulBroadcastReceiver开始做连接的服务。一旦设备进入睡眠状态，一切的伟大工程的前几个小时，但它开始后约4-5小时要失败，我认为该设备将进入的深度睡眠的。

I'm attempting to connect to a paired bluetooth device every 25 seconds, scheduled through AlarmManager which triggers a WakefulBroadcastReceiver to start a service to do the connection. Once the device goes to sleep, everything works great for the first few hours, but it starts to fail after about 4-5 hours, when I assume the device goes into a deep sleep.

我从ParcelFileDescriptor一个NullPointerException异常，陈述的FileDescriptor不能为空。我试图寻找这个错误，甚至通过code在ParcelFileDescriptor.java走了，但我在一个死胡同。我在一台Nexus 10上运行这一点，与Android 4.4.2。在code它试图连接是如下：

I get a NullPointerException from ParcelFileDescriptor, stating the "FileDescriptor must not be null". I've tried searching this error, and have even gone through the code in ParcelFileDescriptor.java, but am at a dead end. I'm running this on a Nexus 10, with Android 4.4.2. The code which tries to connect is below:

public GatewaySocket getSocket() throws IOException
{
    if (!BluetoothAdapter.checkBluetoothAddress(macAddress))
        return new GatewaySocket("Address " + macAddress + " is not a valid Bluetooth MAC Address");

    BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();
    if (bluetooth == null)
        return new GatewaySocket("Sorry, no Bluetooth adapter available");

    BluetoothDevice device = bluetooth.getRemoteDevice(macAddress);

    BluetoothSocket btSocket = null;

    try
    {
        btSocket = device.createRfcommSocketToServiceRecord(uuid);
    }
    catch (Exception e)
    {
        log(3, "" + this, "Error closing socket on connection: " + e);
    }

    if (btSocket == null)
        return new GatewaySocket("Unable to launch insecure connection to " + device);

    try
    {
        btSocket.connect();
    }
    catch (IOException ex)
    {
        try
        {
                btSocket.close();
        }
        catch (IOException ex2)
        {
                // do nothing
        }

    throw (ex);
    }

    GatewaySocket socket = new GatewaySocket(btSocket, btSocket.getInputStream(), btSocket.getOutputStream());

    return socket;
}

GatewaySocket是薄的BluetoothSocket的子类。出现此错误的btSocket.connect（）线，以下堆栈跟踪：

GatewaySocket is a thin subclass of BluetoothSocket. The error occurs at the btSocket.connect() line, with the following stack trace:

01-10 09:13:57.796: W/BluetoothAdapter(3591): getBluetoothService() called with no BluetoothManagerCallback
01-10 09:13:57.801: D/BTIF_SOCK(979): service_uuid: 00001101-0000-1000-8000-00805f9b34fb
01-10 09:13:57.801: E/bt-btif(979): SOCK_THREAD_FD_RD signaled when rfc is not connected, slot id:4374, channel:-1
01-10 09:13:57.801: W/System.err(3591): java.lang.NullPointerException: FileDescriptor must not be null
01-10 09:13:57.806: W/System.err(3591):     at android.os.ParcelFileDescriptor.<init>(ParcelFileDescriptor.java:174)
01-10 09:13:57.806: W/System.err(3591):     at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:905)
01-10 09:13:57.806: W/System.err(3591):     at android.os.ParcelFileDescriptor$1.createFromParcel(ParcelFileDescriptor.java:897)
01-10 09:13:57.806: W/System.err(3591):     at android.bluetooth.IBluetooth$Stub$Proxy.connectSocket(IBluetooth.java:1322)
01-10 09:13:57.806: W/System.err(3591):     at android.bluetooth.BluetoothSocket.connect(BluetoothSocket.java:308)
01-10 09:13:57.806: W/System.err(3591):     at com.gateway.service.AndroidGMConversation.getSocket(AndroidGMConversation.java:162)
01-10 09:13:57.806: W/System.err(3591):     at com.gateway.GatewayManagerConversation.converse(GatewayManagerConversation.java:81)
01-10 09:13:57.806: W/System.err(3591):     at com.gateway.GatewayManagerConversation.run(GatewayManagerConversation.java:72)
01-10 09:13:57.806: W/System.err(3591):     at java.lang.Thread.run(Thread.java:841)
01-10 09:13:57.806: V/PS(3591): Finished with device 06:92:25:0A:A5:50

任何建议将是AP preciated！

Any suggestions would be appreciated!

推荐答案

我已经找到了解决办法经过蓝牙库类后，发现它不关闭的FileDescriptor同时呼吁 bluetoothsocket.close （）; 尽管它调用调度（）法在的FileDescriptor，不关闭它

I have found the workaround after going through the Bluetooth library classes, and found it doesn't close the FileDescriptor while calling bluetoothsocket.close(); despite it calls the dispatch() method over the FileDescriptor, which doesn't close it.

就在打电话之前这个方法 bluetoothsocket.close（）;

Just call this method before the bluetoothsocket.close();

private synchronized void clearFileDescriptor(){
        try{
            Field field = BluetoothSocket.class.getDeclaredField("mPfd");
            field.setAccessible(true);
            ParcelFileDescriptor mPfd = (ParcelFileDescriptor)field.get(socket);
            if(null == mPfd){
                return;
            }

            mPfd.close();
        }catch(Exception e){
            Log.w(SensorTicker.TAG, "LocalSocket could not be cleanly closed.");
        }
    }

希望这会解决其他的问题，以及。但它应该由的BluetoothSocket类在close方法来处理。

Hope this will resolve others problem as well. But it's should be handled by the BluetoothSocket class over the close method.

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