无法使用 ApachePOI android studio write/record 连续数据到 .xls sheet

Question

嗨，我目前正在做我的毕业设计。为此我需要 "record continuous data of sensors from textviews to a .xls sheet"。为此，我正在使用 java 的 Apache POI 库，它允许您创建 excel 工作簿和工作表等。问题是我的代码能够成功创建工作表。但是，当我尝试记录加速度计传感器的变化值（让加速度计仅用于讨论）并将其写入文件时，单击按钮即可出现问题。这是我的代码，来自 android 工作室项目的 .java 文件。

import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Workbook;

import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;

public class MainActivity extends AppCompatActivity implements SensorEventListener, View.OnClickListener {

    public static int i = 1;
    public static boolean a = false;
    public static String filename;

    private SensorManager sensorManager;
    Sensor accelerometer, gyroscope, magnetometer;
    TextView ax, ay, az, gx, gy, gz, mx, my, mz;
    Button btnStart, btnStop;
    Workbook workbook;

    //ArrayList<String> array = new ArrayList<>();
    FileOutputStream fos = null;

    HSSFSheet sheet;
    Row row;
    int rownum = 3;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        ax = findViewById(R.id.valueX);
        ay = findViewById(R.id.valueY);
        az = findViewById(R.id.valueZ);

        gx = findViewById(R.id.gvalueX);
        gy = findViewById(R.id.gvalueY);
        gz = findViewById(R.id.gvalueZ);

        mx = findViewById(R.id.mvalueX);
        my = findViewById(R.id.mvalueY);
        mz = findViewById(R.id.mvalueZ);
        //---------------------------------------------------------------------------------------------------//

        btnStart = findViewById(R.id.btnStart);
        btnStop = findViewById(R.id.btnStop);

        btnStart.setOnClickListener(this);
        btnStop.setOnClickListener(this);

        filename = "File.xls";
        //This is the file, that will be made workbook when doing "workbook.write(fos{filename..})"
        workbook = new HSSFWorkbook();  //creates workbook only once when program is started

        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
        assert sensorManager != null;
        accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        gyroscope = sensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
        magnetometer = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);

        registerListeners(); //a Function.
    }

      private void registerListeners(){
        //Registering the listeners to start recording data
        if (accelerometer != null) {
            sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
        } else {
            Toast.makeText(this, "Accelerometer is not supported", Toast.LENGTH_SHORT).show();
        }

        if (gyroscope != null) {
            sensorManager.registerListener(this, gyroscope, SensorManager.SENSOR_DELAY_NORMAL);
        } else {
            Toast.makeText(this, "Gyroscope is not supported", Toast.LENGTH_SHORT).show();
        }

        if (magnetometer != null) {
            sensorManager.registerListener(this, magnetometer, SensorManager.SENSOR_DELAY_NORMAL);
        } else {
            Toast.makeText(this, "Magnetometer is not supported", Toast.LENGTH_SHORT).show();
        }

    }

    //THIS IS THE PORTION WITH ISSUE .-.
    @Override
    public void onSensorChanged(SensorEvent sensorEvent) {

        Sensor sensor = sensorEvent.sensor;
        if (sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            ax.setText(String.valueOf(sensorEvent.values[0]));
            ay.setText(String.valueOf(sensorEvent.values[1]));
            az.setText(String.valueOf(sensorEvent.values[2]));
        } 
        else if (sensor.getType() == Sensor.TYPE_GYROSCOPE) {

            gx.setText(String.valueOf(sensorEvent.values[0]));
            gy.setText(String.valueOf(sensorEvent.values[1]));
            gz.setText(String.valueOf(sensorEvent.values[2]));
        } 
        else if (sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {

            mx.setText(String.valueOf(sensorEvent.values[0]));
            my.setText(String.valueOf(sensorEvent.values[1]));
            mz.setText(String.valueOf(sensorEvent.values[2]));

        //Here i try to record sensor values... BUT it fails......!!!!!!!!!!!!!
        if(a) {

                if(row!=null) {
                    row = sheet.createRow(rownum);  //rownum =3 (initially)
                    //picking accelerometer values only.
                    row.createCell(0).setCellValue(ax.getText().toString());
                    row.createCell(1).setCellValue(ay.getText().toString());
                    row.createCell(2).setCellValue(az.getText().toString()); 
                }
                try {
                    fos = openFileOutput(filename, MODE_APPEND);
                    ((HSSFWorkbook) workbook).write(fos);
                    Toast.makeText(this, "Done" , Toast.LENGTH_SHORT).show();

                }
                catch (IOException e) {
                    e.printStackTrace();
                }
                rownum++;
            }
      }
 }
     public void onAccuracyChanged(Sensor sensor, int i) {
        //leave it empty for now
      }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.btnStart:
                if(createSheet()){
                    a = true;
                }
                else Toast.makeText(this, "Sheet could not be created", Toast.LENGTH_SHORT).show();
                //i++;
                break;
            case R.id.btnStop:
                a = false;
                //i++;
                Toast.makeText(this, "Values Recorded Successfully", Toast.LENGTH_LONG).show();
                /*try {
                    fos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                } */
                break;
        }
    }

     private boolean createSheet() {  

        try{
            Toast.makeText(this, " " + i, Toast.LENGTH_SHORT).show();
            sheet = ((HSSFWorkbook) workbook).createSheet("Sheet_" + i);
            //Toast.makeText(this, "Sheet " + i, Toast.LENGTH_SHORT).show();
            Cell cell;

            row = sheet.createRow(0);
            cell = row.createCell(0);
            cell.setCellValue("Mobile Phone Sensors Readings");
            //row.createCell(0).setCellValue("Mobile Phone Sensors Readings");

            row = sheet.createRow(1);
            row.createCell(0).setCellValue("Accelerometer");
            row.createCell(3).setCellValue("Gyroscope");
            row.createCell(6).setCellValue("Magnetometer");

            row = sheet.createRow(2);
            row.createCell(0).setCellValue("X-Axis");
            row.createCell(1).setCellValue("Y-axis");
            row.createCell(2).setCellValue("Z-axis");

            row.createCell(3).setCellValue("X-Axis");
            row.createCell(4).setCellValue("Y-axis");
            row.createCell(5).setCellValue("Z-axis");

            row.createCell(6).setCellValue("X-Axis");
            row.createCell(7).setCellValue("Y-axis");
            row.createCell(8).setCellValue("Z-axis");
            try {
                fos = openFileOutput(filename, MODE_APPEND);
                ((HSSFWorkbook) workbook).write(fos);

            }
            catch (IOException e) {
                e.printStackTrace();
                return false;
            }

        }   //try1 ends.
        catch (Exception ex){
            ex.printStackTrace();
            return false;
        }  //catch for try1 ends.

        return true;
    } //createSheet function ends. 
}

有人可以帮忙吗？问题区域在 onSensorValuesChanged() 函数中。

先谢谢了。

Answer 1

我自己解决了这个问题！如果其他人也想看到答案，可以在这里提及。主要问题出在 try-catch 上。我将相同的值记录到我的 .xls sheet.

无法使用 ApachePOI android studio write/record 连续数据到 .xls sheet

Unable to write/record continuous data to a .xls sheet using ApachePOI android studio

java

excel

apache-poi

android-studio

hssfworkbook