如何实现导出sqlite到android中的excel / csv文件？

Question

我正在开发Android应用程序，其中SQlite作为数据库。我想以编程方式将某些结果从DB导出为ex​​cel文件格式，希望将该excel存储到本地设备路径 我遇到了以下链接

• SQlite database programmatically convert into Excel file format in Android

• Android - Generate CSV file from table values

• android exporting to csv and sending as email attachment

那么为Android应用程序实现导出到Excel的确切程序是什么？

Answer 1

这里的家伙是我成功实施的答案

//new async task for file export to csv
private class ExportDatabaseCSVTask extends AsyncTask<String, String, Boolean> {
    private final ProgressDialog dialog = new ProgressDialog(SearchResultActivity.this);
    boolean memoryErr = false;

    // to show Loading dialog box
    @Override
    protected void onPreExecute() {
        this.dialog.setMessage("Exporting database...");
        this.dialog.show();
    }

    // to write process 
    protected Boolean doInBackground(final String... args) {

        boolean success = false;

        String currentDateString = new SimpleDateFormat(Constants.SimpleDtFrmt_ddMMyyyy).format(new Date());

        File dbFile = getDatabasePath("HLPL_FRETE.db");
        Log.v(TAG, "Db path is: " + dbFile); // get the path of db
        File exportDir = new File(Environment.getExternalStorageDirectory() + File.separator + Constants.FileNm.FILE_DIR_NM, "");

        long freeBytesInternal = new File(getApplicationContext().getFilesDir().getAbsoluteFile().toString()).getFreeSpace();           
        long megAvailable = freeBytesInternal / 1048576;

        if (megAvailable < 0.1) {               
            System.out.println("Please check"+megAvailable);
            memoryErr = true;               
        }else {             
            exportDirStr = exportDir.toString();// to show in dialogbox
            Log.v(TAG, "exportDir path::" + exportDir);
            if (!exportDir.exists()) {
                exportDir.mkdirs();
            }   
            try {
                List<SalesActivity> listdata = salesLst;
                SalesActivity sa = null;
                String lob = null;
                for (int index = 0; index < listdata.size();) {
                    sa = listdata.get(index);
                    lob = sa.getLob();
                    break;
                }
                if (Constants.Common.OCEAN_LOB.equals(lob)) {

                    file = new File(exportDir, Constants.FileNm.FILE_OFS + currentDateString + ".csv");
                } else {
                    file = new File(exportDir, Constants.FileNm.FILE_AFS + currentDateString + ".csv");
                }
                file.createNewFile();
                CSVWriter csvWrite = new CSVWriter(new FileWriter(file));


                // this is the Column of the table and same for Header of CSV
                // file
                if (Constants.Common.OCEAN_LOB.equals(lob)) {
                    csvWrite.writeNext(Constants.FileNm.CSV_O_HEADER);
                }else{
                    csvWrite.writeNext(Constants.FileNm.CSV_A_HEADER);
                }
                String arrStr1[] = { "SR.No", "CUTSOMER NAME", "PROSPECT", "PORT OF LOAD", "PORT OF DISCHARGE" };
                csvWrite.writeNext(arrStr1);

                if (listdata.size() > 0) {
                    for (int index = 0; index < listdata.size(); index++) {
                        sa = listdata.get(index);
                        String pol;
                        String pod;
                        if (Constants.Common.OCEAN_LOB.equals(sa.getLob())) {
                            pol = sa.getPortOfLoadingOENm();
                            pod = sa.getPortOfDischargeOENm();
                        } else {
                            pol = sa.getAirportOfLoadNm();
                            pod = sa.getAirportOfDischargeNm();
                        }
                        int srNo = index;
                        String arrStr[] = { String.valueOf(srNo + 1), sa.getCustomerNm(), sa.getProspectNm(), pol, pod };
                        csvWrite.writeNext(arrStr);
                    }
                    success = true;
                }
                csvWrite.close();

            } catch (IOException e) {
                Log.e("SearchResultActivity", e.getMessage(), e);
                return success;
            }
        }
        return success;
    }

    // close dialog and give msg
    protected void onPostExecute(Boolean success) {
        if (this.dialog.isShowing()) {
            this.dialog.dismiss();
        }
        if (success) {
            dialogBox(Constants.Flag.FLAG_EXPRT_S);
        } else {                
            if (memoryErr==true) {
                dialogBox(Constants.Flag.FLAG_MEMORY_ERR);
            } else {
                dialogBox(Constants.Flag.FLAG_EXPRT_F);
            }
        }
    }
}

Answer 2

这是我的答案：这有效！ Excel文件与.csv文件相同。 第1步：下载此jar文件https://code.google.com/p/opencsv/downloads/detail?name=opencsv-2.4.jar&can=2&q=

第2步：

private class ExportDatabaseCSVTask extends AsyncTask<String ,String, String>{
    private final ProgressDialog dialog = new ProgressDialog(MainActivity.this);
    @Override
    protected void onPreExecute() {
        this.dialog.setMessage("Exporting database...");
        this.dialog.show();
    }

    protected String doInBackground(final String... args){
        File exportDir = new File(Environment.getExternalStorageDirectory(), "");
        if (!exportDir.exists()) {
            exportDir.mkdirs();
        }

        File file = new File(exportDir, "ExcelFile.csv");
        try {

            file.createNewFile();
            CSVWriter csvWrite = new CSVWriter(new FileWriter(file));

            //data     
            ArrayList<String> listdata= new ArrayList<String>();
            listdata.add("Aniket");
            listdata.add("Shinde");
            listdata.add("pune");
            listdata.add("anything@anything");
            //Headers
            String arrStr1[] ={"First Name", "Last Name", "Address", "Email"};
            csvWrite.writeNext(arrStr1);

            String arrStr[] ={listdata.get(0), listdata.get(1), listdata.get(2), listdata.get(3)};
            csvWrite.writeNext(arrStr);   

            csvWrite.close();
            return "";
        }
        catch (IOException e){
            Log.e("MainActivity", e.getMessage(), e);
            return "";
        }
    }

    @SuppressLint("NewApi")
    @Override
    protected void onPostExecute(final String success) {

        if (this.dialog.isShowing()){
            this.dialog.dismiss();
        }
        if (success.isEmpty()){
            Toast.makeText(MainActivity.this, "Export successful!", Toast.LENGTH_SHORT).show();
        }
        else {
            Toast.makeText(MainActivity.this, "Export failed!", Toast.LENGTH_SHORT).show();
        }
    }
} 

在.java文件中编写Async任务

步骤3：添加调用此任务

ExportDatabaseCSVTask task=new ExportDatabaseCSVTask();
task.execute();

ExcelFile.csv文件将在您的SD卡中创建。

Answer 3

<强> ExportDatabaseCSVTask ：

 public class ExportDatabaseCSVTask extends AsyncTask<String, Void, Boolean> {
        private final ProgressDialog dialog = new ProgressDialog(MainActivity.this);

        @Override
        protected void onPreExecute() {
            this.dialog.setMessage("Exporting database...");
            this.dialog.show();
        }

        protected Boolean doInBackground(final String... args) {
            String currentDBPath = "/data/"+ "your Package name" +"/databases/abc.db";
            File dbFile = getDatabasePath(""+currentDBPath);
            System.out.println(dbFile);  // displays the data base path in your logcat
            File exportDir = new File(Environment.getExternalStorageDirectory(), "/your Folder Name/");

            if (!exportDir.exists()) { exportDir.mkdirs(); }

            File file = new File(exportDir, "myfile.csv");
            try {
                file.createNewFile();
                CSVWriter csvWrite = new CSVWriter(new FileWriter(file));
                Cursor curCSV = simpledb.rawQuery("select * from " + tablename,null);
                csvWrite.writeNext(curCSV.getColumnNames());
                while(curCSV.moveToNext()) {
                    String arrStr[]=null;
                    String[] mySecondStringArray = new String[curCSV.getColumnNames().length];
                    for(int i=0;i<curCSV.getColumnNames().length;i++)
                    {
                        mySecondStringArray[i] =curCSV.getString(i);
                    }
                    csvWrite.writeNext(mySecondStringArray);
                }
                csvWrite.close();
                curCSV.close();
                return true;
            } catch (IOException e) {
                Log.e("MainActivity", e.getMessage(), e);
                return false;
            }
        }

        protected void onPostExecute(final Boolean success) {
            if (this.dialog.isShowing()) { this.dialog.dismiss(); }
            if (success) {
                 Toast.makeText(MainActivity.this, "Export successful!", Toast.LENGTH_SHORT).show();
            } else {
                Toast.makeText(MainActivity.this, "Export failed", Toast.LENGTH_SHORT).show();
            }
        }
    }

<强> CSVWriter ：

 public class CSVWriter {

private PrintWriter pw;

private char separator;

private char quotechar;

private char escapechar;

private String lineEnd;

/** The character used for escaping quotes. */
public static final char DEFAULT_ESCAPE_CHARACTER = '"';

/** The default separator to use if none is supplied to the constructor. */
public static final char DEFAULT_SEPARATOR = ',';

/**
 * The default quote character to use if none is supplied to the
 * constructor.
 */
public static final char DEFAULT_QUOTE_CHARACTER = '"';

/** The quote constant to use when you wish to suppress all quoting. */
public static final char NO_QUOTE_CHARACTER = '\u0000';

/** The escape constant to use when you wish to suppress all escaping. */
public static final char NO_ESCAPE_CHARACTER = '\u0000';

/** Default line terminator uses platform encoding. */
public static final String DEFAULT_LINE_END = "\n";

/**
 * Constructs CSVWriter using a comma for the separator.
 *
 * @param writer
 *            the writer to an underlying CSV source.
 */
public CSVWriter(Writer writer) {
    this(writer, DEFAULT_SEPARATOR, DEFAULT_QUOTE_CHARACTER,
        DEFAULT_ESCAPE_CHARACTER, DEFAULT_LINE_END);
}

/**
 * Constructs CSVWriter with supplied separator, quote char, escape char and line ending.
 *
 * @param writer
 *            the writer to an underlying CSV source.
 * @param separator
 *            the delimiter to use for separating entries
 * @param quotechar
 *            the character to use for quoted elements
 * @param escapechar
 *            the character to use for escaping quotechars or escapechars
 * @param lineEnd
 *            the line feed terminator to use
 */
public CSVWriter(Writer writer, char separator, char quotechar, char escapechar, String lineEnd) {
    this.pw = new PrintWriter(writer);
    this.separator = separator;
    this.quotechar = quotechar;
    this.escapechar = escapechar;
    this.lineEnd = lineEnd;
}

/**
 * Writes the next line to the file.
 *
 * @param nextLine
 *            a string array with each comma-separated element as a separate
 *            entry.
 */
public void writeNext(String[] nextLine) {

    if (nextLine == null)
        return;

    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < nextLine.length; i++) {

        if (i != 0) {
            sb.append(separator);
        }

        String nextElement = nextLine[i];
        if (nextElement == null)
            continue;
        if (quotechar !=  NO_QUOTE_CHARACTER)
            sb.append(quotechar);
        for (int j = 0; j < nextElement.length(); j++) {
            char nextChar = nextElement.charAt(j);
            if (escapechar != NO_ESCAPE_CHARACTER && nextChar == quotechar) {
                sb.append(escapechar).append(nextChar);
            } else if (escapechar != NO_ESCAPE_CHARACTER && nextChar == escapechar) {
                sb.append(escapechar).append(nextChar);
            } else {
                sb.append(nextChar);
            }
        }
        if (quotechar != NO_QUOTE_CHARACTER)
            sb.append(quotechar);
    }

    sb.append(lineEnd);
    pw.write(sb.toString());

}

/**
 * Flush underlying stream to writer.
 *
 * @throws IOException if bad things happen
 */
public void flush() throws IOException {

    pw.flush();

}

/**
 * Close the underlying stream writer flushing any buffered content.
 *
 * @throws IOException if bad things happen
 *
 */
public void close() throws IOException {
    pw.flush();
    pw.close();
}

 }

Answer 4

我最近在我的应用程序中实现了excel导出功能。我还提供了有关如何将筛选的数据导出到excel而不是整个表格的完整代码。

您将需要为此创建第二个表。第二个将保存执行此操作所需的数据（在我的第二个表中，我删除了我的autoincrament ID列，因为我不想在我的excel文件中使用它。）

您需要先清除第二个表，然后添加条目。

然后使用SqLiteToExcel对象将db导出到excel并将文件保存在某处。

然后我有一个电子邮件意图，其中附加了要共享的excel文件（允许与除电子邮件以外的其他应用程序共享）。这是我的方法：

private void ExportData() {

 //CHECK IF YOU HAVE WRITE PERMISSIONS OR RETURN
int permission = ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE);

if (permission != PackageManager.PERMISSION_GRANTED) {
    Toast.makeText(getContext(), "Storage permissions not granted", Toast.LENGTH_SHORT).show();
    return;
}

//get database object
myDbhelper = new MyDbHelper(getContext());
SQLiteDatabase database = myDbhelper.getWritableDatabase();

//delete all entries in the second table
database.delete("Table2",null,null);

//Create a cursor of the main database with your filters and sort order applied
Cursor cursor = getActivity().getContentResolver().query(
        uri,
        projections,
        selection,
        args,
        sortOrder);

//loop through cursor and add entries from first table to second table
try {
    while (cursor.moveToNext()) {
        final String ColumnOneIndex = cursor.getString(cursor.getColumnIndexOrThrow("COLUMN_ONE"));
        final String ColumnTwoIndex = cursor.getString(cursor.getColumnIndexOrThrow("COLUMN_TWO"));
        final String ColumnThreeIndex = cursor.getString(cursor.getColumnIndexOrThrow("COLUMN_THREE"));

  //add entries from table one into the table two
        ContentValues values = new ContentValues();
        values.put("TABLE2_COLUMN_1", ColumnOneIndex);
        values.put("TABLE2_COLUMN_2", ColumnTwoIndex );
        values.put("TABLE2_COLUMN_3", ColumnThreeIndex);

        database.insert("table2", null, values);
    }
} finally {
    //close cursor after looping is complete
    cursor.close();
}

 //create a string for where you want to save the excel file
final String savePath = Environment.getExternalStorageDirectory() + "/excelfileTemp";
File file = new File(savePath);
if (!file.exists()) {
    file.mkdirs();
}
 //create the sqLiteToExcel object
SQLiteToExcel sqLiteToExcel = new SQLiteToExcel(getContext(), "databasefile.db",savePath);

//use sqLiteToExcel object to create the excel file 
sqLiteToExcel.exportSingleTable("table2","excelfilename.xls", new SQLiteToExcel.ExportListener() {
    @Override
    public void onStart() {

    }
    @Override
    public void onCompleted(String filePath) {
        //now attach the excel file created and be directed to email activity
        Uri newPath = Uri.parse("file://" + savePath + "/" +"excelfilename.xls");

        StrictMode.VmPolicy.Builder builder = new StrictMode.VmPolicy.Builder();
        StrictMode.setVmPolicy(builder.build());

        Intent emailintent = new Intent(Intent.ACTION_SEND);

        emailintent.setType("application/vnd.ms-excel");
        emailintent.putExtra(Intent.EXTRA_SUBJECT, "Subject");
        emailintent.putExtra(Intent.EXTRA_TEXT, "I'm email body.");
        emailintent.putExtra(Intent.EXTRA_STREAM,newPath);

        startActivity(Intent.createChooser(emailintent, "Send Email"));
    }
    @Override
    public void onError(Exception e) {
        System.out.println("Error msg: " + e);
        Toast.makeText(getContext(), "Failed to Export data", Toast.LENGTH_SHORT).show();
    }
});
}

我已经在我的应用中实现了此方法，并且有效

Answer 5

每行的CSV格式为“字符串，字符串，字符串/ n”， “，”是列分隔符，“ / n”是行。 从数据库中获取数据并像这样导出它们：

public static Boolean exportToCSV(List<Data> data, File file) {
    try {
        final String head = "ValueX, ValueY \n";

        if (!file.exists()) {
            file.createNewFile();
        }

        FileWriter fileWriter = new FileWriter(file.getAbsoluteFile());
        BufferedWriter writer = new BufferedWriter(fileWriter);
        writer.write(head);

        for (Item item : items) {
            final String line = String.format("%s,%s\n",
                    item.getValueX(),
                    item.getValueY());
            writer.write(line);
        }

        writer.close();
    } catch (IOException e) {
        return false;
    }

    return true;
}