java如何按原样发送字节数,而不是在Android Bluetooth outputStream中作为单个数字发送?
我想发送,例如:239作为239通过我的蓝牙输出流,但目前,我的蓝牙代码发送它作为“2”,然后是“3”,然后是“9”;总共3个字节,而不是1个字节,接收也发生在3个字节中
发送端代码(Java): 使用计时器每10秒发送一次数据
包装数据如下:
private void startTimer() {
TimerTask mTimerTask = new TimerTask() {
@RequiresApi(api = Build.VERSION_CODES.KITKAT)
@Override
public void run() {
byte[] mByte = new byte[1];
mTimeStamp += mPeriod; //mPeriod = 10000; initial mTimeStamp = 0
mData += 2; //initial mData = 0
String s = "239";
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mTimeStamp & 0xFF000000) >> 24));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mTimeStamp & 0x00FF0000) >> 16));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mTimeStamp & 0x0000FF00) >> 8));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mTimeStamp & 0x000000FF) >> 0));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = "0";
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = "0";
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mData & 0x0000FF00) >> 8));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
s = Integer.toString(((mData & 0x000000FF) >> 0));
mByte = s.getBytes(StandardCharsets.UTF_8);
mBluetoothConnection.write(mByte);
}
};
Timer timer = new Timer("schedule", true);
timer.scheduleAtFixedRate(mTimerTask, 10, mPeriod);
}
以及写入功能:
//Call this from the main activity to send data to the remote device
public void write(byte[] bytes) {
String text = new String(bytes, Charset.defaultCharset());
Log.d(TAG, "write: Writing to outputstream: " + text);
try {
Log.d(TAG, "write: bytes length: " + bytes.length);
mmOutStream.write(bytes);
} catch (IOException e) {
Log.e(TAG, "write: Error writing to output stream. " + e.getMessage() );
}
}
记录相同的cat输出:
01-06 23:33:32.012 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 239
01-06 23:33:32.012 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 3
01-06 23:33:32.018 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.018 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 0
01-06 23:33:32.018 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 1
01-06 23:33:32.020 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.020 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 4
01-06 23:33:32.020 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 1
01-06 23:33:32.021 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.021 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 147
01-06 23:33:32.021 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 3
01-06 23:33:32.022 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.022 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 224
01-06 23:33:32.022 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 3
01-06 23:33:32.024 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.024 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 0
01-06 23:33:32.024 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 1
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 0
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 1
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 0
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 1
01-06 23:33:32.033 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Write Called.
01-06 23:33:32.034 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: Writing to outputstream: 60
01-06 23:33:32.034 19455-19682/com.example.user.bluetooth_communication D/BluetoothConnectionServ: write: bytes length: 2
接收端(Kotlin)的代码:
// Keep listening to the InputStream until an exception occurs
Log.d("ConnectionActivity", "Inside ListeningThread")
while (true) { // Read from the InputStream
if(mBluetoothSocket != null)
{
try {
bytes = mBluetoothSocket!!.inputStream.read(buffer)
val incomingMessage = String(buffer, 0, bytes)
Log.d("ConnectionActivity", "No of bytes: $bytes, " + "InputStream: $incomingMessage")
var intentIncomingMessage = Intent("incomingMessage")
intentIncomingMessage.putExtra("theMessage", incomingMessage)
LocalBroadcastManager.getInstance(mContext).sendBroadcast(intentIncomingMessage)
} catch (e: IOException) {
Log.e(TAG, "write: Error reading Input Stream. " + e.message)
break
}
}
}
logcat输出示例:
2020-01-12 16:12:10.817 13707-13937 D/ConnectionActivity: No of bytes: 3, InputStream: 239
2020-01-12 16:12:10.848 13707-13937 D/ConnectionActivity: No of bytes: 12, InputStream: 074324000094
2020-01-12 16:12:20.817 13707-13937 D/ConnectionActivity: No of bytes: 3, InputStream: 239
2020-01-12 16:12:20.842 13707-13937 D/ConnectionActivity: No of bytes: 10, InputStream: 0783000096
2020-01-12 16:12:30.817 13707-13937 D/ConnectionActivity: No of bytes: 3, InputStream: 239
2020-01-12 16:12:30.845 13707-13937 D/ConnectionActivity: No of bytes: 12, InputStream: 071221600098
在上面的输出中,我需要的是:前两行数据应该是
D/ConnectionActivity: No of bytes: 1, InputStream: 239
D/ConnectionActivity: No of bytes: 1, InputStream: 0
D/ConnectionActivity: No of bytes: 1, InputStream: 74
D/ConnectionActivity: No of bytes: 1, InputStream: 32
D/ConnectionActivity: No of bytes: 1, InputStream: 40
D/ConnectionActivity: No of bytes: 1, InputStream: 0
D/ConnectionActivity: No of bytes: 1, InputStream: 0
D/ConnectionActivity: No of bytes: 1, InputStream: 0
D/ConnectionActivity: No of bytes: 1, InputStream: 94
我认为这个问题部分(如果不是全部)与我如何传输数据有关。在Tx侧logcat输出中,可以看到239的字节长度被打印为3,而不是1
# 1 楼答案
一些java流基础知识:
这应该允许您发送原始字节,而无需转换字符串
在Kotlin中,如果需要无符号字节,可以将
.toUByte()
添加到inputStream.readByte()