Android蓝牙开发(二)经典蓝牙消息传输实现

上篇文章中,我们主要介绍了蓝牙模块,传统/经典蓝牙模块BT和低功耗蓝牙BLE及其相关的API,不熟悉的可以查看Android蓝牙开发(一)蓝牙模块及核心API 进行了解。

本篇主要记录用到的经典蓝牙开发流程及连接通讯。

1. 开启蓝牙

蓝牙连接前,给与相关系统权限:

<!-- 使用蓝牙的权限 -->
<uses-permission android:name="android.permission.BLUETOOTH" />
<!-- 扫描蓝牙设备或者操作蓝牙设置 -->
<uses-permission android:name="android.permission.BLUETOOTH_ADMIN" />
<!--模糊定位权限,仅作用于6.0+-->
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<!--精准定位权限,仅作用于6.0+-->
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

安卓6.0以上系统要动态请求及获取开启GPS内容:

/**
 * 检查GPS是否打开
 */
private boolean checkGPSIsOpen() {
    LocationManager locationManager = (LocationManager) mContext.getSystemService(Context.LOCATION_SERVICE);
    if (locationManager == null)
        return false;
    return locationManager.isProviderEnabled(android.location.LocationManager.GPS_PROVIDER);
}

蓝牙核心对象获取,若获取对象为null则说明设备不支持蓝牙:

mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();

判断蓝牙是否开启,没有则开启:

//判断蓝牙是否开启
if (!mBluetoothAdapter.isEnabled()) {
    //开启蓝牙,耗时,监听广播进行后续操作
    mBluetoothAdapter.enable();
}

2.扫描蓝牙

蓝牙扫描:

mBluetoothAdapter.startDiscovery();

取消扫描:

mBluetoothAdapter.cancelDiscovery();

3.蓝牙状态监听

蓝牙监听广播,监听蓝牙开关,发现设备,扫描结束等状态,定义状态回调接口,进行对应操作,例如:监听到蓝牙开启后,进行设备扫描;发现设备后进行连接等。

/**
 * 监听蓝牙广播-各种状态
 */
public class BluetoothReceiver extends BroadcastReceiver {
    private static final String TAG = BluetoothReceiver.class.getSimpleName();
    private final OnBluetoothReceiverListener mOnBluetoothReceiverListener;

    public BluetoothReceiver(Context context,OnBluetoothReceiverListener onBluetoothReceiverListener) {
        mOnBluetoothReceiverListener = onBluetoothReceiverListener;
        context.registerReceiver(this,getBluetoothIntentFilter());
    }

    private IntentFilter getBluetoothIntentFilter() {
        IntentFilter filter = new IntentFilter();
        filter.addAction(BluetoothAdapter.ACTION_STATE_CHANGED);//蓝牙开关状态
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);//蓝牙开始搜索
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);//蓝牙搜索结束
        filter.addAction(BluetoothDevice.ACTION_FOUND);//蓝牙发现新设备(未配对的设备)
        return filter;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (action == null) {
            return;
        }
        Log.i(TAG, "===" + action);
        BluetoothDevice dev = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
        if (dev != null) {
            Log.i(TAG, "BluetoothDevice: " + dev.getName() + ", " + dev.getAddress());
        }
        switch (action) {
            case BluetoothAdapter.ACTION_STATE_CHANGED:
                int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE, 0);
                Log.i(TAG, "STATE: " + state);
                if (mOnBluetoothReceiverListener != null) {
                    mOnBluetoothReceiverListener.onStateChanged(state);
                }
                break;
            case BluetoothAdapter.ACTION_DISCOVERY_STARTED:
                Log.i(TAG, "ACTION_DISCOVERY_STARTED ");
                break;
            case BluetoothAdapter.ACTION_DISCOVERY_FINISHED:
                if (mOnBluetoothReceiverListener != null) {
                    mOnBluetoothReceiverListener.onScanFinish();
                }
                break;
            case BluetoothDevice.ACTION_FOUND:
                short rssi = intent.getShortExtra(BluetoothDevice.EXTRA_RSSI, Short.MAX_VALUE);
                Log.i(TAG, "EXTRA_RSSI:" + rssi);
                if (mOnBluetoothReceiverListener != null) {
                    mOnBluetoothReceiverListener.onDeviceFound(dev);
                }
                break;
            default:
                break;
        }
    }

    public interface OnBluetoothReceiverListener {
        /**
         * 发现设备
         *
         * @param bluetoothDevice 蓝牙设备
         */
        void onDeviceFound(BluetoothDevice bluetoothDevice);

        /**
         * 扫描结束
         */
        void onScanFinish();

        /**
         * 蓝牙开启关闭状态
         *
         * @param state 状态
         */
        void onStateChanged(int state);
    }
}

4.通讯连接

客户端,与服务端建立长连接,进行通讯:

/**
 * 客户端,与服务端建立长连接
 */
public class BluetoothClient extends BaseBluetooth {

    public BluetoothClient(BTListener BTListener) {
        super(BTListener);
    }

    /**
     * 与远端设备建立长连接
     *
     * @param bluetoothDevice 远端设备
     */
    public void connect(BluetoothDevice bluetoothDevice) {
        close();
        try {
//             final BluetoothSocket socket = bluetoothDevice.createRfcommSocketToServiceRecord(SPP_UUID); //加密传输,Android强制执行配对,弹窗显示配对码
            final BluetoothSocket socket = bluetoothDevice.createInsecureRfcommSocketToServiceRecord(SPP_UUID); //明文传输(不安全),无需配对
            // 开启子线程(必须在新线程中进行连接操作)
            EXECUTOR.execute(new Runnable() {
                @Override
                public void run() {
                    //连接,并进行循环读取
                    loopRead(socket);
                }
            });
        } catch (Throwable e) {
            close();
        }
    }
}

服务端监听客户端发起的连接,进行接收及通讯:

/**
 * 服务端监听和连接线程,只连接一个设备
 */
public class BluetoothServer extends BaseBluetooth {
    private BluetoothServerSocket mSSocket;

    public BluetoothServer(BTListener BTListener) {
        super(BTListener);
        listen();
    }

    /**
     * 监听客户端发起的连接
     */
    public void listen() {
        try {
            BluetoothAdapter adapter = BluetoothAdapter.getDefaultAdapter();
//            mSSocket = adapter.listenUsingRfcommWithServiceRecord("BT", SPP_UUID); //加密传输,Android强制执行配对,弹窗显示配对码
            mSSocket = adapter.listenUsingInsecureRfcommWithServiceRecord("BT", SPP_UUID); //明文传输(不安全),无需配对
            // 开启子线程
            EXECUTOR.execute(new Runnable() {
                @Override
                public void run() {
                    try {
                        BluetoothSocket socket = mSSocket.accept(); // 监听连接
                        mSSocket.close(); // 关闭监听,只连接一个设备
                        loopRead(socket); // 循环读取
                    } catch (Throwable e) {
                        close();
                    }
                }
            });
        } catch (Throwable e) {
            close();
        }
    }

    @Override
    public void close() {
        super.close();
        try {
            mSSocket.close();
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
}

客户端连接及服务端监听基类,用于客户端和服务端之前Socket消息通讯,进行消息或文件的发送、接收,进行通讯关闭操作等:

public class BaseBluetooth {
    public static final Executor EXECUTOR = Executors.newSingleThreadExecutor();
    protected static final UUID SPP_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB"); //自定义
    private static final String FILE_PATH = Environment.getExternalStorageDirectory().getAbsolutePath() + "/bluetooth/";
    private static final int FLAG_MSG = 0;  //消息标记
    private static final int FLAG_FILE = 1; //文件标记

    private BluetoothSocket mSocket;
    private DataOutputStream mOut;
    private BTListener mBTListener;
    private boolean isRead;
    private boolean isSending;

    public BaseBluetooth(BTListener BTListener) {
        mBTListener = BTListener;
    }

    /**
     * 循环读取对方数据(若没有数据,则阻塞等待)
     */
    public void loopRead(BluetoothSocket socket) {
        mSocket = socket;
        try {
            if (!mSocket.isConnected())
                mSocket.connect();
            notifyUI(BTListener.CONNECTED, mSocket.getRemoteDevice());
            mOut = new DataOutputStream(mSocket.getOutputStream());
            DataInputStream in = new DataInputStream(mSocket.getInputStream());
            isRead = true;
            while (isRead) { //循环读取
                switch (in.readInt()) {
                    case FLAG_MSG: //读取短消息
                        String msg = in.readUTF();
                        notifyUI(BTListener.MSG_RECEIVED, msg);
                        break;
                    case FLAG_FILE: //读取文件
                        File file = new File(FILE_PATH);
                        if (!file.exists()) {
                            file.mkdirs();
                        }
                        String fileName = in.readUTF(); //文件名
                        long fileLen = in.readLong(); //文件长度
                        notifyUI(BTListener.MSG_RECEIVED, "正在接收文件(" + fileName + ")····················");
                        // 读取文件内容
                        long len = 0;
                        int r;
                        byte[] b = new byte[4 * 1024];
                        FileOutputStream out = new FileOutputStream(FILE_PATH + fileName);
                        while ((r = in.read(b)) != -1) {
                            out.write(b, 0, r);
                            len += r;
                            if (len >= fileLen)
                                break;
                        }
                        notifyUI(BTListener.MSG_RECEIVED, "文件接收完成(存放在:" + FILE_PATH + ")");
                        break;
                }
            }
        } catch (Throwable e) {
            close();
        }
    }

    /**
     * 发送短消息
     */
    public void sendMsg(String msg) {
        if (isSending || TextUtils.isEmpty(msg))
            return;
        isSending = true;
        try {
            mOut.writeInt(FLAG_MSG); //消息标记
            mOut.writeUTF(msg);
        } catch (Throwable e) {
            close();
        }
        notifyUI(BTListener.MSG_SEND, "发送短消息:" + msg);
        isSending = false;
    }

    /**
     * 发送文件
     */
    public void sendFile(final String filePath) {
        if (isSending || TextUtils.isEmpty(filePath))
            return;
        isSending = true;
        EXECUTOR.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    notifyUI(BTListener.MSG_SEND, "正在发送文件(" + filePath + ")····················");
                    FileInputStream in = new FileInputStream(filePath);
                    File file = new File(filePath);
                    mOut.writeInt(FLAG_FILE); //文件标记
                    mOut.writeUTF(file.getName()); //文件名
                    mOut.writeLong(file.length()); //文件长度
                    int r;
                    byte[] b = new byte[4 * 1024];
                    while ((r = in.read(b)) != -1) {
                        mOut.write(b, 0, r);
                    }
                    notifyUI(BTListener.MSG_SEND, "文件发送完成.");
                } catch (Throwable e) {
                    close();
                }
                isSending = false;
            }
        });
    }

    /**
     * 关闭Socket连接
     */
    public void close() {
        try {
            isRead = false;
            if (mSocket != null) {
                mSocket.close();
                notifyUI(BTListener.DISCONNECTED, null);
            }
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }

    /**
     * 当前设备与指定设备是否连接
     */
    public boolean isConnected(BluetoothDevice dev) {
        boolean connected = (mSocket != null && mSocket.isConnected());
        if (dev == null)
            return connected;
        return connected && mSocket.getRemoteDevice().equals(dev);
    }

    private void notifyUI(final int state, final Object obj) {
        mBTListener.socketNotify(state, obj);
    }

    public interface BTListener {
        int DISCONNECTED = 0;
        int CONNECTED = 1;
        int MSG_SEND = 2;
        int MSG_RECEIVED = 3;

        void socketNotify(int state, Object obj);
    }

我这里只是简单记录了项目中用到的蓝牙通讯,两个设备之间不通过配对进行连接、通讯。
相关详细内容及使用请查看Github项目:https://github.com/MickJson/BluetoothCS

蓝牙配对操作及其它内容,可以详细查看我下面的参考资料,写的十分详细,比如设备通过MAC地址,可以通过BluetoothAdapter获取设备,再通过客户端connect方法去进行连接等。

BluetoothDevice btDev = mBluetoothAdapter.getRemoteDevice(address);

最后

连接中遇到问题:read failed, socket might closed or timeout, read ret: -1。

通过改UUID,反射等方法都还是会出现错误。连接时,要确保服务端及客户端都处于完全断开状态,否则连接就会出现以上问题,但偶尔还是会有问题,期待有什么好的方法可留言告诉我。

参考资料:

Android-经典蓝牙(BT)-建立长连接传输短消息和文件

Android蓝牙开发—经典蓝牙详细开发流程

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posted @ 2020-08-11 16:42  几圈年轮  阅读(2443)  评论(0编辑  收藏  举报