MainActivity.java

package pro.kondratev.xlsxpoiexample;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.text.SimpleDateFormat;

import org.apache.poi.hssf.usermodel.HSSFDateUtil;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellValue;
import org.apache.poi.ss.usermodel.FormulaEvaluator;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.util.WorkbookUtil;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class MainActivity extends Activity {

    EditText output;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        output = (EditText) findViewById(R.id.textOut);
    }

    public void onReadClick(View view) {
        printlnToUser("reading XLSX file from resources");
        InputStream stream = getResources().openRawResource(R.raw.test1);
        try {
            XSSFWorkbook workbook = new XSSFWorkbook(stream);
            XSSFSheet sheet = workbook.getSheetAt(0);
            int rowsCount = sheet.getPhysicalNumberOfRows();
            FormulaEvaluator formulaEvaluator = workbook.getCreationHelper().createFormulaEvaluator();
            for (int r = 0; r<rowsCount; r++) {
                Row row = sheet.getRow(r);
                int cellsCount = row.getPhysicalNumberOfCells();
                for (int c = 0; c<cellsCount; c++) {
                    String value = getCellAsString(row, c, formulaEvaluator);
                    String cellInfo = "r:"+r+"; c:"+c+"; v:"+value;
                    printlnToUser(cellInfo);
                }
            }
        } catch (Exception e) {
            /* proper exception handling to be here */
            printlnToUser(e.toString());
        }
    }

    public void onWriteClick(View view) {
        printlnToUser("writing xlsx file");
        //XXX: Using blank template file as a workaround to make it work
        //Original library contained something like 80K methods and I chopped it to 60k methods
        //so, some classes are missing, and some things not working properly
        InputStream stream = getResources().openRawResource(R.raw.template);
        try {
            XSSFWorkbook workbook = new XSSFWorkbook(stream);
            XSSFSheet sheet = workbook.getSheetAt(0);
            //XSSFWorkbook workbook = new XSSFWorkbook();
            //XSSFSheet sheet = workbook.createSheet(WorkbookUtil.createSafeSheetName("mysheet"));
            for (int i=0;i<10;i++) {
                Row row = sheet.createRow(i);
                Cell cell = row.createCell(0);
                cell.setCellValue(i);
            }
            String outFileName = "filetoshare.xlsx";
            printlnToUser("writing file " + outFileName);
            File cacheDir = getCacheDir();
            File outFile = new File(cacheDir, outFileName);
            OutputStream outputStream = new FileOutputStream(outFile.getAbsolutePath());
            workbook.write(outputStream);
            outputStream.flush();
            outputStream.close();
            printlnToUser("sharing file...");
            share(outFileName, getApplicationContext());
        } catch (Exception e) {
            /* proper exception handling to be here */
            printlnToUser(e.toString());
        }
    }

    protected String getCellAsString(Row row, int c, FormulaEvaluator formulaEvaluator) {
        String value = "";
        try {
            Cell cell = row.getCell(c);
            CellValue cellValue = formulaEvaluator.evaluate(cell);
            switch (cellValue.getCellType()) {
                case Cell.CELL_TYPE_BOOLEAN:
                    value = ""+cellValue.getBooleanValue();
                    break;
                case Cell.CELL_TYPE_NUMERIC:
                    double numericValue = cellValue.getNumberValue();
                    if(HSSFDateUtil.isCellDateFormatted(cell)) {
                        double date = cellValue.getNumberValue();
                        SimpleDateFormat formatter =
                                new SimpleDateFormat("dd/MM/yy");
                        value = formatter.format(HSSFDateUtil.getJavaDate(date));
                    } else {
                        value = ""+numericValue;
                    }
                    break;
                case Cell.CELL_TYPE_STRING:
                    value = ""+cellValue.getStringValue();
                    break;
                default:
            }
        } catch (NullPointerException e) {
            /* proper error handling should be here */
            printlnToUser(e.toString());
        }
        return value;
    }

    /**
     * print line to the output TextView
     * @param str
     */
    private void printlnToUser(String str) {
        final String string = str;
        if (output.length()>8000) {
            CharSequence fullOutput = output.getText();
            fullOutput = fullOutput.subSequence(5000,fullOutput.length());
            output.setText(fullOutput);
            output.setSelection(fullOutput.length());
        }
        output.append(string+"\n");
    }

    public void share(String fileName, Context context) {
        Uri fileUri = Uri.parse("content://"+getPackageName()+"/"+fileName);
        printlnToUser("sending "+fileUri.toString()+" ...");
        Intent shareIntent = new Intent();
        shareIntent.setAction(Intent.ACTION_SEND);
        shareIntent.putExtra(Intent.EXTRA_STREAM, fileUri);
        shareIntent.setType("application/octet-stream");
        startActivity(Intent.createChooser(shareIntent, getResources().getText(R.string.send_to)));
    }

}