Android WebRTC利用DataChannel收发文本数据和传输文件

一、概述

　　利用WebRTC的DataChannel发送文本数据以及传输文件

二、实例代码演示

　　1.初始化DataChannel以及注册DataChannel的回调函数

 /**
     * 创建DataChannel
     *
     * @param socketId 用户id
     * @return 数据通道
     */
    public DataChannel createDataChannel(String socketId, PeerConnection peerConnection) {
        if (dataChannelInit == null) {
            /**
             DataChannel.Init 可配参数说明：
             ordered：是否保证顺序传输；
             maxRetransmitTimeMs：重传允许的最长时间；
             maxRetransmits：重传允许的最大次数；
             */
            dataChannelInit = new DataChannel.Init();
            dataChannelInit.ordered = true; // 消息的传递是否有序 true代表有序
            dataChannelInit.negotiated = true; // 协商方式
            dataChannelInit.id = 0; // 通道ID
        }
        if (dataChannel == null) {
            dataChannel = peerConnection.createDataChannel("dataChannel", dataChannelInit);
            //注册DataChannel的回调函数
            dataChannel.registerObserver(new DataChannel.Observer() {
                boolean isHeader = true;
                String suffix = null;
                int fileLength = 0;
                long currentLength = 0;
                boolean isFinish = false;
                List<byte[]> queue = new ArrayList<>();

                //
                @Override
                public void onBufferedAmountChange(long l) {

                }

                //状态发生改变
                @Override
                public void onStateChange() {

                }

                /**
                 * 接收二进制消息时需要定义一个简单的header用于存放文件信息
                 * 1.filename 文件名
                 * 2.suffix  后缀名
                 * 3.totalLength 文件总大小
                 * @param buffer
                 */
                //接收消息
                @Override
                public void onMessage(DataChannel.Buffer buffer) {
                    try {
                        ByteBuffer data = buffer.data;
                        byte[] bytes = new byte[data.capacity()];
                        Log.e(TAG, "initDataChannel----->onMessage--->" + bytes.length);
                        data.get(bytes);
                        if (dataChannelListener != null) {
                            if (buffer.binary) {//是二进制数据
                                if (isHeader) {
                                    isHeader = false;//为false时就不是第一次，只有第一次需要检测文件后缀
                                    //检测文件后缀
                                    byte[] headerPayload = new byte[200];
                                    System.arraycopy(bytes, 0, headerPayload, 0, 200);
                                    String filePath = ByteUtil.getInstance().getStringFromByteArray(headerPayload);
                                    byte[] lengthPayload = new byte[200];
                                    System.arraycopy(bytes, 200, lengthPayload, 0, 20);
                                    String length = ByteUtil.getInstance().getStringFromByteArray(lengthPayload);
                                    Log.e(TAG, "initDataChannel----->onMessage--->filePath---->" + filePath);
                                    Log.e(TAG, "initDataChannel----->onMessage--->length---->" + length);
                                    suffix = FileUtils.getInstance().getFileSuffix(filePath);
                                    fileLength = Integer.parseInt(length) - 220;
                                    Log.e(TAG, "initDataChannel----->onMessage--->suffix---->" + suffix);
                                }
                                if (!isHeader) {
                                    currentLength += bytes.length;
                                    if ((currentLength - 220) >= fileLength) {
                                        isFinish = true;
                                    }
                                    queue.add(bytes);
                                    float progress = (currentLength / (float) fileLength) * 100;
                                    dataChannelListener.onReceiveFileProgress(progress);
                                }
                                if (isFinish) {
                                    String realPath = null;
//                                    for (int i = 0; i < queue.size(); i++) {
//                                        isFinish = false;
//                                        if (i == queue.size() - 1) {
//                                            isFinish = true;
//                                        }
//
////
//                                    }

                                    queue.remove(0);
                                    realPath = FileUtils.getInstance().writeBytesToFile(context, suffix, queue);
                                    if (realPath != null) {
                                        Log.e(TAG, "initDataChannel----->onMessage--->realPath----> 执行了多少次");
                                        dataChannelListener.onReceiveBinaryMessage(socketId, realPath);
                                    }

                                }

                            } else {//不是二进制数据
                                //此处接收的是非二进制数据
                                String msg = new String(bytes);
                                dataChannelListener.onReceiveMessage(socketId, msg);
                            }

                        }
                    } catch (Exception e) {
                        e.printStackTrace();
                    }

                }
            });
        }
        return dataChannel;
    }

　　2.接收及发送文本消息　

/**
     * 使用DataChannel发送普通消息
     *
     * @param message
     */
    public void sendMsg(String message) {
        if (dataChannel != null) {
            if (message != null) {
                byte[] msg = message.getBytes();
                DataChannel.Buffer buffer = new DataChannel.Buffer(ByteBuffer.wrap(msg), false);
                dataChannel.send(buffer);
            }
        }


    }　

//接收普通文本消息
client.setDataChannelListener(new DataChannelListenerImpl() {
            @Override
            public void onReceiveMessage(String userId, String message) {
                mainHandler.post(() -> {
                    sb.append(userId).append(":").append(message).append("
");
                    tvContent.setText(sb.toString());
                });

            }


        });

　　3.接收及发送文件

 /**
     * 使用DataChannel发送二进制消息
     *
     * @param bytes
     */
    public void sendBinary(byte[] bytes) {
        if (dataChannel != null) {
            DataChannel.Buffer buffer = new DataChannel.Buffer(ByteBuffer.wrap(bytes), true);
            dataChannel.send(buffer);
        }
    }　

client.setDataChannelListener(new DataChannelListenerImpl() {

           
//接收文件消息成功回调以及，显示文件接收的进度
 @Override
            public void onReceiveBinaryMessage(String userId, String realPath) {
                handler.post(() -> {
                    tvReceiveFileName.setText(realPath);
                });
            }

            @Override
            public void onReceiveFileProgress(float progress) {
                handler.post(() -> {
                    tvReceiveFileName.setText(progress+"%");
                });

            }


        });