最近接了一个新需求：
内容： 通过手机app实现蓝牙连接称重设备，实现app获取设备重量并接入业务
语言以及工具：
1、flutter + java安卓原生
2、某某牌蓝牙称重蓝牙硬件板块（称榜上拆下来的）：
前面走过的坑（只对于我接手的项目而已，并不是说以下文档插件不好）：
1、flutter_weigh_serial 1.0.0+2
这个插件我试了，但是和我的gradle版本不兼容，就被我舍弃了
2、bluetooth_print 这个热敏蓝牙打印插件我也试了，可以搜索到该蓝牙设备，但是连接不了
最后没办法，还是老老实实写原生方法
1、建立flutter与原生通道
new MethodChannel(Objects.requireNonNull(getFlutterEngine()).getDartExecutor().getBinaryMessenger(), WEIGHTGET)
.setMethodCallHandler((call, result) -> {
if (call.method.equals("getCount")) {
System.out.println("连接状态" + isopen);
if(isopen){
mBLE_Service.disconnect();
isopen = false;
result.success(isopen);
return;
}
isopen = true;
///==========================
Intent data = getIntent();
mdevice = data.getParcelableExtra("Device");
UART_UUID = data.getStringExtra("DeviceUART");
TXO_UUID = data.getStringExtra("DeviceTXO");
RXI_UUID = data.getStringExtra("DeviceRXI");
// sevice = UUID.fromString(UART_UUID);
// txo = UUID.fromString(TXO_UUID);
// rxi = UUID.fromString(RXI_UUID);
sevice = UUID.fromString("0000FFE0-0000-1000-8000-00805F9B34FB");
txo = UUID.fromString("0000FFE1-0000-1000-8000-00805F9B34FB");
rxi = UUID.fromString("0000FFE1-0000-1000-8000-00805F9B34FB");
// 如果 mdevice 为 null 或者需要设置默认地址
if (mdevice == null || mdevice.getAddress() == null || mdevice.getAddress().isEmpty()) {
String defaultAddress = "88:25:83:F4:F7:4A";
mdevice = BluetoothAdapter.getDefaultAdapter().getRemoteDevice(defaultAddress);
}
mBLE_Service.setUUID(sevice,txo,rxi);
mBLE_Service.disconnect();
mBLE_Service.connect(mdevice, this);
result.success(isopen);
/======================
} else {
result.notImplemented();
}
});
上面的UUID直接写死固定设备，包括设备的蓝牙地址我都是先直接写死
2、监听蓝牙模块的响应数据
SpBLE mBLE_Service;
mBLE_Service = new SpBLE(this,mHandler);
封装好的蓝牙服务类文件
package com.example.yunhan_demo;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;
/**
* This class does all the work for setting up and managing Bluetooth
* connections with other devices. It has a thread that listens for
* incoming connections, a thread for connecting with a device, and a
* thread for performing data transmissions when connected.
*/
public class BluetoothChatService {
// Debugging
private static final String TAG = "BluetoothChatService";
private static final boolean D = true;
// Name for the SDP record when creating server socket
private static final String NAME = "BluetoothCom";
// Unique UUID for this application //Bluetooth serial board
private static final UUID MY_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
//private static final UUID MY_UUID = UUID.fromString("fa87c0d0-afac-11de-8a39-0800200c9a66");
//Hint: If you are connecting to a Bluetooth serial board then try using the well-known SPP UUID 00001101-0000-1000-8000-00805F9B34FB.
//However if you are connecting to an Android peer then please generate your own unique UUID.
// Member fields
private final BluetoothAdapter mAdapter;
private final Handler mHandler;
private AcceptThread mAcceptThread;
private ConnectThread mConnectThread;
private ConnectedThread mConnectedThread;
private int mState;
// Constants that indicate the current connection state
public static final int STATE_NONE = 0; // we're doing nothing
public static final int STATE_LISTEN = 1; // now listening for incoming connections
public static final int STATE_CONNECTING = 2; // now initiating an outgoing connection
public static final int STATE_CONNECTED = 3; // now connected to a remote device
/**
* Constructor. Prepares a new BluetoothChat session.
* @param context The UI Activity Context
* @param handler A Handler to send messages back to the UI Activity
*/
public BluetoothChatService(Context context, Handler handler) {
mAdapter = BluetoothAdapter.getDefaultAdapter();
mState = STATE_NONE;
mHandler = handler;
}
/**
* Set the current state of the chat connection
* @param state An integer defining the current connection state
*/
private synchronized void setState(int state) {
if (D) Log.d(TAG, "setState() " + mState + " -> " + state);
mState = state;
// Give the new state to the Handler so the UI Activity can update
mHandler.obtainMessage(MainActivity.MESSAGE_STATE_CHANGE, state, -1).sendToTarget();
}
/**
* Return the current connection state. */
public synchronized int getState() {
return mState;
}
/**
* Start the chat service. Specifically start AcceptThread to begin a
* session in listening (server) mode. Called by the Activity onResume() */
public synchronized void start() {
if (D) Log.d(TAG, "start");
// Cancel any thread attempting to make a connection
if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
// Start the thread to listen on a BluetoothServerSocket
if (mAcceptThread == null) {
mAcceptThread = new AcceptThread();
mAcceptThread.start();
}
setState(STATE_LISTEN);
}
/**
* Start the ConnectThread to initiate a connection to a remote device.
* @param device The BluetoothDevice to connect
*/
public synchronized void connect(BluetoothDevice device) {
if (D) Log.d(TAG, "connect to: " + device);
// Cancel any thread attempting to make a connection
if (mState == STATE_CONNECTING) {
if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
// Start the thread to connect with the given device
mConnectThread = new ConnectThread(device);
mConnectThread.start();
setState(STATE_CONNECTING);
}
/**
* Start the ConnectedThread to begin managing a Bluetooth connection
* @param socket The BluetoothSocket on which the connection was made
* @param device The BluetoothDevice that has been connected
*/
public synchronized void connected(BluetoothSocket socket, BluetoothDevice device) {
if (D) Log.d(TAG, "connected");
// Cancel the thread that completed the connection
if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
// Cancel any thread currently running a connection
if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
// Cancel the accept thread because we only want to connect to one device
if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}
// Start the thread to manage the connection and perform transmissions
mConnectedThread = new ConnectedThread(socket);
mConnectedThread.start();
// Send the name of the connected device back to the UI Activity
Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_DEVICE_NAME);
Bundle bundle = new Bundle();
bundle.putString(MainActivity.DEVICE_NAME, device.getName());
msg.setData(bundle);
mHandler.sendMessage(msg);
setState(STATE_CONNECTED);
}
/**
* Stop all threads
*/
public synchronized void stop() {
if (D) Log.d(TAG, "stop");
if (mConnectThread != null) {mConnectThread.cancel(); mConnectThread = null;}
if (mConnectedThread != null) {mConnectedThread.cancel(); mConnectedThread = null;}
if (mAcceptThread != null) {mAcceptThread.cancel(); mAcceptThread = null;}
setState(STATE_NONE);
}
/**
* Write to the ConnectedThread in an unsynchronized manner
* @param out The bytes to write
* @see ConnectedThread#write(byte[])
*/
public void write(byte[] out) {
// Create temporary object
ConnectedThread r;
// Synchronize a copy of the ConnectedThread
synchronized (this) {
if (mState != STATE_CONNECTED) return;
r = mConnectedThread;
}
// Perform the write unsynchronized
r.write(out);
}
/**
* Indicate that the connection attempt failed and notify the UI Activity.
*/
private void connectionFailed() {
setState(STATE_LISTEN);
// Send a failure message back to the Activity
Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putString(MainActivity.TOAST, "连接失败");
msg.setData(bundle);
mHandler.sendMessage(msg);
}
/**
* Indicate that the connection was lost and notify the UI Activity.
*/
private void connectionLost() {
setState(STATE_LISTEN);
// Send a failure message back to the Activity
Message msg = mHandler.obtainMessage(MainActivity.MESSAGE_TOAST);
Bundle bundle = new Bundle();
bundle.putString(MainActivity.TOAST, "蓝牙已断开连接");
msg.setData(bundle);
mHandler.sendMessage(msg);
}
/**
* This thread runs while listening for incoming connections. It behaves
* like a server-side client. It runs until a connection is accepted
* (or until cancelled).
*/
private class AcceptThread extends Thread {
// The local server socket
private final BluetoothServerSocket mmServerSocket;
public AcceptThread() {
BluetoothServerSocket tmp = null;
// Create a new listening server socket
try {
tmp = mAdapter.listenUsingRfcommWithServiceRecord(NAME, MY_UUID);
} catch (IOException e) {
Log.e(TAG, "listen() failed", e);
}
mmServerSocket = tmp;
}
public void run() {
if (D) Log.d(TAG, "BEGIN mAcceptThread" + this);
setName("AcceptThread");
BluetoothSocket socket = null;
// Listen to the server socket if we're not connected
while (mState != STATE_CONNECTED) {
try {
// This is a blocking call and will only return on a
// successful connection or an exception
socket = mmServerSocket.accept();
} catch (IOException e) {
// Log.e(TAG, "accept() failed", e);
break;
}
// If a connection was accepted
if (socket != null) {
synchronized (BluetoothChatService.this) {
switch (mState) {
case STATE_LISTEN:
case STATE_CONNECTING:
// Situation normal. Start the connected thread.
connected(socket, socket.getRemoteDevice());
break;
case STATE_NONE:
case STATE_CONNECTED:
// Either not ready or already connected. Terminate new socket.
try {
socket.close();
} catch (IOException e) {
Log.e(TAG, "Could not close unwanted socket", e);
}
break;
}
}
}
}
if (D) Log.i(TAG, "END mAcceptThread");
}
public void cancel() {
if (D) Log.d(TAG, "cancel " + this);
try {
mmServerSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of server failed", e);
}
}
}
/**
* This thread runs while attempting to make an outgoing connection
* with a device. It runs straight through; the connection either
* succeeds or fails.
*/
private class ConnectThread extends Thread {
private final BluetoothSocket mmSocket;
private final BluetoothDevice mmDevice;
public ConnectThread(BluetoothDevice device) {
mmDevice = device;
BluetoothSocket tmp = null;
// Get a BluetoothSocket for a connection with the
// given BluetoothDevice
try {
tmp = device.createRfcommSocketToServiceRecord(MY_UUID);
} catch (IOException e) {
Log.e(TAG, "create() failed", e);
}
mmSocket = tmp;
}
public void run() {
Log.i(TAG, "BEGIN mConnectThread");
setName("ConnectThread");
// Always cancel discovery because it will slow down a connection
mAdapter.cancelDiscovery();
// Make a connection to the BluetoothSocket
try {
// This is a blocking call and will only return on a
// successful connection or an exception
mmSocket.connect();
} catch (IOException e) {
connectionFailed();
// Close the socket
try {
mmSocket.close();
} catch (IOException e2) {
Log.e(TAG, "unable to close() socket during connection failure", e2);
}
// Start the service over to restart listening mode
BluetoothChatService.this.start();
return;
}
// Reset the ConnectThread because we're done
synchronized (BluetoothChatService.this) {
mConnectThread = null;
}
// Start the connected thread
connected(mmSocket, mmDevice);
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
/**
* This thread runs during a connection with a remote device.
* It handles all incoming and outgoing transmissions.
*/
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG, "create ConnectedThread");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
// Get the BluetoothSocket input and output streams
try {
tmpIn = socket.getInputStream();
tmpOut = socket.getOutputStream();
} catch (IOException e) {
Log.e(TAG, "temp sockets not created", e);
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run() {
Log.i(TAG, "BEGIN mConnectedThread");
byte[] buffer = new byte[1024];
byte[] buffer2 = new byte[1024];
int bytes;
int i;
// Keep listening to the InputStream while connected
while (true) {
try {
// Read from the InputStream
bytes = mmInStream.read(buffer);
if(bytes>0){
buffer2=buffer.clone();
for(i=0;i<buffer.length;i++)buffer[i]=0;
// Send the obtained bytes to the UI Activity
mHandler.obtainMessage(MainActivity.MESSAGE_READ, bytes, -1, buffer2)
.sendToTarget();
}
} catch (IOException e) {
//Log.e(TAG, "disconnected", e);
connectionLost();
break;
}
}
}
/**
* Write to the connected OutStream.
* @param buffer The bytes to write
*/
public void write(byte[] buffer) {
try {
mmOutStream.write(buffer);
// Share the sent message back to the UI Activity
mHandler.obtainMessage(MainActivity.MESSAGE_WRITE, buffer.length, -1, buffer)
.sendToTarget();
} catch (IOException e) {
Log.e(TAG, "Exception during write", e);
}
}
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) {
Log.e(TAG, "close() of connect socket failed", e);
}
}
}
}
3、处理获取蓝牙板块响应的数据
private final Handler mHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
switch (msg.what) {
case 2:
byte[] readBuf = (byte[]) msg.obj;
String readMessage = null;
rxcount += msg.arg1;
rxs += msg.arg1;
Display_Data(readBuf,msg.arg1,false);
}
}
};
格式转换
void Display_Data(byte[] dat,int len,boolean isSend){
String msg = "";
boolean hex = false;
// if(isSend){
// hex =((CheckBox) (findViewById(R.id.txhex))).isChecked();
// }else hex =((CheckBox) (findViewById(R.id.rxhex))).isChecked();
if(hex) {
try {
msg = getHexString(dat, 0, len);
} catch (UnsupportedEncodingException e) {
throw new RuntimeException("Unsupported encoding type.");
}
}else {
try{
msg = new String(dat, 0, len,"GBK");
}catch (UnsupportedEncodingException e){
throw new RuntimeException("Unsupported encoding type.");
}
}
show_data(msg);
//if(isSend)Add_Sended(msg);
//else Add_Readed(msg);
}
public void show_data(String t){
weighStr = t;
System.out.println("获取接收称重数据" + weighStr);
}
最后在show_data里拿到的是打印数据
如图所示
VID_20241025_180518
完整代码我有时间会上传到仓库