我无法读取通过蓝牙从 Arduino Uno 接收到的数据，但我知道 Arduino 正在向我发送一些数据。
我收到错误:
W/System.err: at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:537)
at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:96)
at java.io.InputStream.read(InputStream.java:101)
at bikit.chaptal.MainDisp$SendReceive.run(MainDisp.java:250)
at bikit.chaptal.MainDisp$SendReceive.<init>(MainDisp.java:239)
at bikit.chaptal.MainDisp$ConnectBT.doInBackground(MainDisp.java:200)
at bikit.chaptal.MainDisp$ConnectBT.doInBackground(MainDisp.java:168)
at android.os.AsyncTask$2.call(AsyncTask.java:345)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:257)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
at java.lang.Thread.run(Thread.java:784)
java.io.IOException: bt socket closed, read return: -1
at android.bluetooth.BluetoothSocket.read(BluetoothSocket.java:537)
at android.bluetooth.BluetoothInputStream.read(BluetoothInputStream.java:96)
at java.io.InputStream.read(InputStream.java:101)
at bikit.chaptal.MainDisp$SendReceive.run(MainDisp.java:250)
at bikit.chaptal.MainDisp$SendReceive.<init>(MainDisp.java:239)
at bikit.chaptal.MainDisp$ConnectBT.doInBackground(MainDisp.java:200)
at bikit.chaptal.MainDisp$ConnectBT.doInBackground(MainDisp.java:168)
at android.os.AsyncTask$2.call(AsyncTask.java:345)
at java.util.concurrent.FutureTask.run(FutureTask.java:266)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:257)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1162)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:636)
at java.lang.Thread.run(Thread.java:784)
java.io.IOException: bt socket closed, read return: -1
这是有问题的代码部分:
public class SendReceive extends Thread
{
private InputStream inputStream;
private OutputStream outputStream;
public SendReceive ( BluetoothSocket socket )
{
try {
inputStream = mmSocket.getInputStream();
outputStream = mmSocket.getOutputStream();
}catch (IOException e ) {
e.printStackTrace();
}
if(inputStream != null){
run();
}
}
public void run()
{
byte[] buffer = new byte[1024];
int bytes;
while (true) {
try {
bytes = inputStream.read(buffer);
handler.obtainMessage(STATE_MESSAGE_RECEIVED, bytes, -1,buffer).sendToTarget();
} catch (IOException e) {
e.printStackTrace();
}
}
}
public void write (byte[] bytes)
{
try {
outputStream.write(bytes);
} catch (IOException e) {
e.printStackTrace();
}
}
}
处理程序:
Handler handler = new Handler(new Handler.Callback() {
@Override
public boolean handleMessage(Message msg) {
switch (msg.what)
{
case STATE_MESSAGE_RECEIVED:
byte[]readBuff = (byte[]) msg.obj;
if (bytes == 1){
Nbatt = readBuff[0];
bytes++;
}
else if (bytes == 2){
tempfloat = ByteBuffer.wrap(new byte[]{readBuff[1]}).getFloat();
temp = Float.toString(tempfloat);
resetbytes(); //bytes++;
}
else if (bytes == 3){
speed = readBuff[2];
resetbytes();
}
break;
}
return false;
}
});
应用程序应该读取不同的字节并显示它们。我不明白这个错误，有人可以向我解释一下吗？
最佳答案
不深入分析代码，我们可以看出问题是由于IOException异常导致的InputStream.read()操作引起的，具体如下:bt socket closeed ，阅读 所以看起来连接已以某种方式断开。根据一些论坛的说法，这是因为该库太旧了，而且自 Android 4.2 以来，BT 堆栈已经发生了变化。
无论如何，有一个解决方法可以通过在出现此异常时实例化回退来使其工作:IOException: read failed, socket might closed - Bluetooth on Android 4.3
关于java - 无法读取蓝牙接收到的数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/56148562/