将存储在SQLite数据库中的经度和纬度数据导出到文件中以便可以通过网站将其导入Google Map API的最简单方法？

Question

我创建了一个应用程序，该应用程序在SQLite数据库中记录一系列经度和纬度值，并将其在MapActivity上显示为彩色轨道。

现在，我希望能够以某种方式导出此数据（最好是导出到文件），以便用户可以将这些值上载到显示Google Map API的网站。

我的问题是：将数据（以及文件格式：GPX，XML和CSV）导出到Android设备上的SD卡的最快方法是什么。

非常感谢。

Answer 1

确定，只需在您的Android项目中添加此类（并进行相应的修改）

public class DatabaseAssistant
{
    private static final String EXPORT_FILE_NAME = "/sdcard/datanaexport.xml";

    private Context _ctx;
    private SQLiteDatabase _db;
    private Exporter _exporter;

    public DatabaseAssistant( Context ctx, SQLiteDatabase db )
    {
        _ctx = ctx;
        _db = db;

        try
        {
            // create a file on the sdcard to export the
            // database contents to
            File myFile = new File( EXPORT_FILE_NAME );
                        myFile.createNewFile();

                        FileOutputStream fOut =  new FileOutputStream(myFile);
                        BufferedOutputStream bos = new BufferedOutputStream( fOut );

            _exporter = new Exporter( bos );
        }
        catch (FileNotFoundException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    public void exportData( )
    {
        log( "Exporting Data" );

        try
        {
            _exporter.startDbExport( _db.getPath() );

            // get the tables out of the given sqlite database
                    String sql = "SELECT * FROM sqlite_master";

                    Cursor cur = _db.rawQuery( sql, new String[0] );
                    Log.d("db", "show tables, cur size " + cur.getCount() );
                    cur.moveToFirst();

                    String tableName;
                    while ( cur.getPosition() < cur.getCount() )
                    {
                        tableName = cur.getString( cur.getColumnIndex( "name" ) );
                        log( "table name " + tableName );

                        // don't process these two tables since they are used
                        // for metadata
                        if ( ! tableName.equals( "android_metadata" ) &&
                        ! tableName.equals( "sqlite_sequence" ) )
                        {
                            exportTable( tableName );
                        }

                        cur.moveToNext();
                    }
                _exporter.endDbExport();
            _exporter.close();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }

    private void exportTable( String tableName ) throws IOException
    {
        _exporter.startTable(tableName);

        // get everything from the table
        String sql = "select * from " + tableName;
        Cursor cur = _db.rawQuery( sql, new String[0] );
        int numcols = cur.getColumnCount();

        log( "Start exporting table " + tableName );

//      // logging
//      for( int idx = 0; idx < numcols; idx++ )
//      {
//          log( "column " + cur.getColumnName(idx) );
//      }

        cur.moveToFirst();

        // move through the table, creating rows
        // and adding each column with name and value
        // to the row
        while( cur.getPosition() < cur.getCount() )
        {
            _exporter.startRow();
            String name;
            String val;
            for( int idx = 0; idx < numcols; idx++ )
            {
                name = cur.getColumnName(idx);
                val = cur.getString( idx );
                log( "col '" + name + "' -- val '" + val + "'" );

                _exporter.addColumn( name, val );
            }

            _exporter.endRow();
            cur.moveToNext();
        }

        cur.close();

        _exporter.endTable();
    }

    private void log( String msg )
    {
        Log.d( "DatabaseAssistant", msg );
    }

    class Exporter
    {
        private static final String CLOSING_WITH_TICK = "'>";
        private static final String START_DB = "<export-database name='";
        private static final String END_DB = "</export-database>";
        private static final String START_TABLE = "<table name='";
        private static final String END_TABLE = "</table>";
        private static final String START_ROW = "<row>";
        private static final String END_ROW = "</row>";
        private static final String START_COL = "<col name='";
        private static final String END_COL = "</col>";

        private BufferedOutputStream _bos;

        public Exporter() throws FileNotFoundException
        {
            this( new BufferedOutputStream(
                    _ctx.openFileOutput( EXPORT_FILE_NAME,
                    Context.MODE_WORLD_READABLE ) ) );
        }

        public Exporter( BufferedOutputStream bos )
        {
            _bos = bos;
        }

        public void close() throws IOException
        {
            if ( _bos != null )
            {
                _bos.close();
            }
        }

        public void startDbExport( String dbName ) throws IOException
        {
            String stg = START_DB + dbName + CLOSING_WITH_TICK;
            _bos.write( stg.getBytes() );
        }

        public void endDbExport() throws IOException
        {
            _bos.write( END_DB.getBytes() );
        }

        public void startTable( String tableName ) throws IOException
        {
            String stg = START_TABLE + tableName + CLOSING_WITH_TICK;
            _bos.write( stg.getBytes() );
        }

        public void endTable() throws IOException
        {
            _bos.write( END_TABLE.getBytes() );
        }

        public void startRow() throws IOException
        {
            _bos.write( START_ROW.getBytes() );
        }

        public void endRow() throws IOException
        {
            _bos.write( END_ROW.getBytes() );
        }

        public void addColumn( String name, String val ) throws IOException
        {
            String stg = START_COL + name + CLOSING_WITH_TICK + val + END_COL;
            _bos.write( stg.getBytes() );
        }
    }

    class Importer
    {

    }

}

不可靠的DatabaseAssistant类

DatabaseAssistant DA = new DatabaseAssistant(myContext, mySQLiteDatabase);

您要导出数据吗？？？所以…

DA.exportData();

;）希望有帮助！

豪尔赫西斯