Android Studio蓝牙发送数据错误

Question

在尝试发送存储在textadim变量中的数据时，我遇到了一个问题。我希望变量是一个介于0和10之间的int，但我收到的是255或254作为值。请帮帮我

下面是我的代码：

package com.led_on_off.led;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.view.View;
import android.widget.ImageButton;
import android.widget.Toast;
import android.app.ProgressDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.os.AsyncTask;
import java.util.Random;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
import android.app.Activity;
import android.content.Context;
import java.io.IOException;
import java.util.UUID;


public class ledControl extends ActionBarActivity  implements SensorEventListener {
   SensorManager sm;
    TextView tv;
    int stepsCount = 0;
    private boolean mInitialized;
    double mLastX;
    double mLastY;
    double mLastZ;
    int textAdim = 0;

    private final float NOISE = (float) 2.0;



   // Button btnOn, btnOff, btnDis;
    ImageButton On, Off, Discnt, Abt;
    String address = null;
    private ProgressDialog progress;
    BluetoothAdapter myBluetooth = null;
    BluetoothSocket btSocket = null;
    private boolean isBtConnected = false;
    //SPP UUID. Look for it
    static final UUID myUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);

        Intent newint = getIntent();
        address = newint.getStringExtra(DeviceList.EXTRA_ADDRESS); //receive the address of the bluetooth device

        //view of the ledControl
        setContentView(R.layout.activity_led_control);

          tv=(TextView)findViewById(R.id.text1);

        mInitialized = false;
        //get sensor service
        sm=(SensorManager)this.getSystemService(Context.SENSOR_SERVICE);
        //Tell which sensor you are going to use
        //And declare delay of sensor
        //Register all to your sensor object to use
        sm.registerListener(this,sm.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
                SensorManager.SENSOR_DELAY_NORMAL);



        //call the widgets
        On = (ImageButton)findViewById(R.id.on);
        Off = (ImageButton)findViewById(R.id.off);
        Discnt = (ImageButton)findViewById(R.id.discnt);
        Abt = (ImageButton)findViewById(R.id.abt);

        new ConnectBT().execute(); //Call the class to connect

        //commands to be sent to bluetooth
        On.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                turnOnLed();      //method to turn on
            }
        });

        Off.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                turnOffLed();   //method to turn off
            }
        });

        Discnt.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v)
            {
                Disconnect(); //close connection
            }
        });


    }

    private void Disconnect()
    {
        if (btSocket!=null) //If the btSocket is busy
        {
            try
            {
                btSocket.close(); //close connection
            }
            catch (IOException e)
            { msg("Error");}
        }
        finish(); //return to the first layout

    }

    private void turnOffLed()
    {
        if (btSocket!=null)
        {
            try
            {
                btSocket.getOutputStream().write("0".toString().getBytes());
            }
            catch (IOException e)
            {
                msg("Error");
            }
        }
    }

    private void turnOnLed()
    {
        if (btSocket!=null)
        {
            try
            {
                btSocket.getOutputStream().write(String.valueOf(textAdim).getBytes());
            }
            catch (IOException e)
            {
                msg("Error");
            }
        }
    }

    // fast way to call Toast
    private void msg(String s)
    {
        Toast.makeText(getApplicationContext(),s,Toast.LENGTH_LONG).show();
    }

    public  void about(View v)
    {
        if(v.getId() == R.id.abt)
        {
            Intent i = new Intent(this, AboutActivity.class);
            startActivity(i);
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_led_control, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }



    private class ConnectBT extends AsyncTask<Void, Void, Void>  // UI thread
    {
        private boolean ConnectSuccess = true; //if it's here, it's almost connected

        @Override
        protected void onPreExecute()
        {
            progress = ProgressDialog.show(ledControl.this, "Connecting...", "Please wait!!!");  //show a progress dialog
        }

        @Override
        protected Void doInBackground(Void... devices) //while the progress dialog is shown, the connection is done in background
        {
            try
            {
                if (btSocket == null || !isBtConnected)
                {
                 myBluetooth = BluetoothAdapter.getDefaultAdapter();//get the mobile bluetooth device
                 BluetoothDevice dispositivo = myBluetooth.getRemoteDevice(address);//connects to the device's address and checks if it's available
                 btSocket = dispositivo.createInsecureRfcommSocketToServiceRecord(myUUID);//create a RFCOMM (SPP) connection
                 BluetoothAdapter.getDefaultAdapter().cancelDiscovery();
                 btSocket.connect();//start connection
                }
            }
            catch (IOException e)
            {
                ConnectSuccess = false;//if the try failed, you can check the exception here
            }
            return null;
        }
        @Override
        protected void onPostExecute(Void result) //after the doInBackground, it checks if everything went fine
        {
            super.onPostExecute(result);

            if (!ConnectSuccess)
            {
                msg("Connection Failed. Is it a SPP Bluetooth? Try again.");
                finish();
            }
            else
            {
                msg("Connected.");
                isBtConnected = true;
            }
            progress.dismiss();
        }
    }

     @Override
    public void onAccuracyChanged(Sensor sensor, int accuracy)
    {
        // TODO Auto-generated method stub
    }
    //This method is called when your mobile moves any direction
    @Override
    public void onSensorChanged(SensorEvent event) {
        // event object contains values of acceleration, read those
        double x = event.values[0];
        double y = event.values[1];
        double z = event.values[2];

        final double alpha = 0.8; // constant for our filter below

        double[] gravity = {0,0,0};

        // Isolate the force of gravity with the low-pass filter.
        gravity[0] = alpha * gravity[0] + (1 - alpha) * event.values[0];
        gravity[1] = alpha * gravity[1] + (1 - alpha) * event.values[1];
        gravity[2] = alpha * gravity[2] + (1 - alpha) * event.values[2];

// Remove the gravity contribution with the high-pass filter.
        x = event.values[0] - gravity[0];
        y = event.values[1] - gravity[1];
        z = event.values[2] - gravity[2];

        if (!mInitialized) {
            // sensor is used for the first time, initialize the last read values
          double  mLastX = x;
            double mLastY = y;
            double  mLastZ = z;
            mInitialized = true;
        } else {
            // sensor is already initialized, and we have previously read values.
            // take difference of past and current values and decide which
            // axis acceleration was detected by comparing values

            double deltaX = Math.abs(mLastX - x);
            double deltaY = Math.abs(mLastY - y);
            double deltaZ = Math.abs(mLastZ - z);
            if (deltaX < NOISE)
                deltaX = (float) 0.0;
            if (deltaY < NOISE)
                deltaY = (float) 0.0;
            if (deltaZ < NOISE)
                deltaZ = (float) 0.0;
            mLastX = x;
            mLastY = y;
            mLastZ = z;

            if (deltaX > deltaY) {
                // Horizontal shake
                // do something here if you like

            } else if (deltaY > deltaX) {
                // Vertical shake
                // do something here if you like

            } else if ((deltaZ > deltaX) && (deltaZ > deltaY)) {
                // Z shake
                stepsCount = stepsCount + 1;
                if (stepsCount > 0) {
                    tv.setText(String.valueOf(stepsCount));
                  textAdim = stepsCount;
               }




// Just for indication purpose, I have added vibrate function
                // whenever our count moves past multiple of 10

        }
    }
    }




    }

Answer 1

您正在写入一个传递二进制数据的流。使用String.ValueOf(textAdim).GetBytes()时，您首先将Int转换为String，然后将其转换为该String的二进制表示形式。为了读取流另一端的值，您需要首先对数据进行解码。

我认为这个答案很好地解释了正在发生的事情。