我可以用从蓝牙获取数据的文件编写器保存

时间：2018-04-29 10:02:14

标签： java android bluetooth arduino

我正在开发android项目以接收来自蓝牙设备h6的蓝牙信号。然后在内部将此数据保存在我的应用程序中。现在我可以从设备获取数据。但是trooblr仍然无法在内部保存数据。在这段代码中，编译错误正在发生。我无法理解如何解决这个错误。我正在使用android studio 3.1.2并使用27 Api版本。我的Java鳕鱼是

package com.example.randikawann.androidbluetoothh6;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.Intent;
import android.media.MediaScannerConnection;
import android.os.Handler;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.util.Set;
import java.util.UUID;
import java.io.FileOutputStream;
import java.io.FileWriter;


public class MainActivity extends AppCompatActivity {




    //    private final String DEVICE_NAME="MyBTBee";
    private final String DEVICE_ADDRESS="20:15:07:27:46:85";
    private final UUID PORT_UUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");//Serial Port Service ID
    private static final String TAG = "MyActivity";
    private BluetoothDevice device;
    private BluetoothSocket socket;
    private OutputStream outputStream;
    private InputStream inputStream;
    Button startButton, sendButton,clearButton,stopButton;
    TextView textView;
    EditText editText;
    boolean deviceConnected=false;
    Thread thread;
    byte buffer[];
    int bufferPosition;
    boolean stopThread;
    String string;
    private static final String FILE_NAME = "example.txt";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        startButton = (Button) findViewById(R.id.buttonStart);
        sendButton = (Button) findViewById(R.id.buttonSend);
        clearButton = (Button) findViewById(R.id.buttonClear);
        stopButton = (Button) findViewById(R.id.buttonStop);
        editText = (EditText) findViewById(R.id.editText);
        textView = (TextView) findViewById(R.id.textView);
        setUiEnabled(false);

    }

    public void setUiEnabled(boolean bool)
    {
        startButton.setEnabled(!bool);
        sendButton.setEnabled(bool);
        stopButton.setEnabled(bool);
        textView.setEnabled(bool);

    }

    public boolean BTinit()
    {
        boolean found=false;
        BluetoothAdapter bluetoothAdapter=BluetoothAdapter.getDefaultAdapter();
        if (bluetoothAdapter == null) {
            Toast.makeText(getApplicationContext(),"Device doesnt Support Bluetooth",Toast.LENGTH_SHORT).show();
        }
        if(!bluetoothAdapter.isEnabled())
            Toast.makeText(getApplicationContext(),"Bluetooth adapter not anabled",Toast.LENGTH_SHORT).show();
        {
            Intent enableAdapter = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
            startActivityForResult(enableAdapter, 0);
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        Set<BluetoothDevice> bondedDevices = bluetoothAdapter.getBondedDevices();
        Toast.makeText(getApplicationContext(),"find bounded device",Toast.LENGTH_SHORT).show();
        if(bondedDevices.isEmpty())
        {
            Toast.makeText(getApplicationContext(),"Please Pair the Device first",Toast.LENGTH_SHORT).show();
        }
        else
        {
            for (BluetoothDevice iterator : bondedDevices)
            {
                if(iterator.getAddress().equals(DEVICE_ADDRESS))
                {
                    device=iterator;
                    found=true;
                    break;
                }
            }
        }
        return found;
    }

    public boolean BTconnect()
    {
        boolean connected=true;
        try {
            socket = device.createRfcommSocketToServiceRecord(PORT_UUID);
            socket.connect();
        } catch (IOException e) {
            e.printStackTrace();
            connected=false;
        }
        if(connected)
        {
            try {
                outputStream=socket.getOutputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }
            try {
                inputStream=socket.getInputStream();
            } catch (IOException e) {
                e.printStackTrace();
            }

        }


        return connected;
    }

    public void onClickStart(View view) {
        if(BTinit())
        {
            if(BTconnect())
            {
                setUiEnabled(true);
                deviceConnected=true;
                beginListenForData();
                textView.append("\nConnection Opened!\n");
            }

        }
    }

    void beginListenForData()
    {
        final Handler handler = new Handler();
        stopThread = false;
        buffer = new byte[1024];
        Thread thread  = new Thread(new Runnable()
        {
            public void run()
            {
                while(!Thread.currentThread().isInterrupted() && !stopThread) {
                    try {
                        int byteCount = inputStream.available();
                        if (byteCount > 0) {
                            byte[] rawBytes = new byte[byteCount];
                            inputStream.read(rawBytes);
                            string = new String(rawBytes, "UTF-8");
                            handler.post(new Runnable() {
                                public void run() {
                                    textView.setText(string);
                                    Log.i(TAG, "***************************" + string);

                                    //store value from file
                                    save();
                                }


                            });

                        }
                    } catch (IOException ex) {
                        stopThread = true;
                    }
                }
            }
        });

        thread.start();
    }
    //Save input value
    public void save() {
        String text = string;
        FileOutputStream fos = null;

        try {
            fos = openFileOutput(FILE_NAME, MODE_PRIVATE);
            fos.write(text.getBytes());

            Toast.makeText(this, "Saved to " + getFilesDir() + "/" + FILE_NAME,
                    Toast.LENGTH_LONG).show();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fos != null) {
                try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
    //Read saved files
    public void load(View v) {
        FileInputStream fis = null;

        try {
            fis = openFileInput(FILE_NAME);
            InputStreamReader isr = new InputStreamReader(fis);
            BufferedReader br = new BufferedReader(isr);
            StringBuilder sb = new StringBuilder();
            String text;

            while ((text = br.readLine()) != null) {
                sb.append(text).append("\n");
            }

            editText.setText(sb.toString());

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public void onClickSend(View view) {
        String string = editText.getText().toString();
        string.concat("\n");
        try {
            outputStream.write(string.getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
        textView.append("\nSent Data:"+string+"\n");

    }

    public void onClickStop(View view) throws IOException {
        stopThread = true;
        outputStream.close();
        inputStream.close();
        socket.close();
        setUiEnabled(false);
        deviceConnected=false;
        textView.append("\nConnection Closed!\n");
    }

    public void onClickClear(View view) {
        textView.setText("");
    }
}

我的活动xml文件也是

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:minHeight="14dp"
    tools:context=".MainActivity"
    tools:layout_editor_absoluteY="81dp">

    <EditText
        android:id="@+id/editText"
        android:layout_width="364dp"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true"
        android:layout_marginLeft="10dp"
        android:layout_marginStart="10dp"
        android:layout_marginTop="70dp"
        android:inputType=""
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/buttonStart"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true"
        android:layout_below="@+id/editText"
        android:layout_marginLeft="10dp"
        android:layout_marginStart="10dp"
        android:layout_marginTop="50dp"
        android:onClick="onClickStart"
        android:text="@string/begin"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:ignore="OnClick" />

    <Button
        android:id="@+id/buttonSend"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText"
        android:layout_marginEnd="196dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="196dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="50dp"
        android:layout_toEndOf="@+id/buttonStart"
        android:layout_toRightOf="@+id/buttonStart"
        android:onClick="onClickSend"
        android:text="@string/send"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/buttonStart"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:ignore="OnClick,UnknownId" />


    <Button
        android:id="@+id/button0Stop"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText"
        android:layout_marginLeft="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="50dp"
        android:layout_toEndOf="@+id/buttonSend"
        android:layout_toRightOf="@+id/buttonSend"
        android:onClick="onClickStop"
        android:text="@string/stop"
        app:layout_constraintStart_toEndOf="@+id/buttonSend"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:ignore="OnClick" />

    <Button
        android:id="@+id/buttonClear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/editText"
        android:layout_marginLeft="5dp"
        android:layout_marginStart="5dp"
        android:layout_marginTop="50dp"
        android:onClick="onClickClear"
        android:text="@string/clear"
        app:layout_constraintStart_toEndOf="@+id/button0Stop"
        app:layout_constraintTop_toBottomOf="@+id/editText"
        tools:ignore="OnClick" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="183dp"
        android:layout_height="111dp"
        android:layout_marginEnd="157dp"
        android:layout_marginRight="157dp"
        android:layout_marginTop="92dp"
        android:text="TextView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/buttonStart" />

</android.support.constraint.ConstraintLayout>

并且编译错误是enter image description here。我希望你的回答

1 个答案:

答案 0 :(得分：0)

关于文件保存，在Android（6.0+）中，我必须在/ data目录中写文件，只有权限才能写（没有明确权限）

示例：

 String directory = "/Android/data/" + getPackageName();

 String pathToSave = directory + "/" + FILE_NAME;

关于错误，我需要更多详情

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