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POExporting SQLite Table data as XML
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2013-01-21T12:41:56.913
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2013-01-22T08:25:22.037
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2017-05-23T12:12:16.930
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I am getting a Null pointer Exception while trying to export my SQLite database's table into an XML file. StackTrace: PasteBin <a href="http://pastebin.com/cZu5gg2B" rel="nofollow noreferrer">Link</a> -- Update 2: I just don't get it of what is passed in(at time of initializing and calling the exportData Method in Main Activity): <code>DatabaseAssistant DA = new DatabaseAssistant(myContext, **WHAT_IS_PASSED_HERE?**); DA.exportData();</code> -- Update: Lines mentioned where I get NPE are: at <code>com.astix.reachout.DatabaseAssistant.exportData(DatabaseAssistant.java:72</code> & <code>com.astix.reachout.ReachOutMain$9.onClick(ReachOutMain.java:347)</code> Which are <code>_exporter.startDbExport( _db.getPath() );</code> available inside <code>DA.exportData()</code> -- I referred to <a href="https://stackoverflow.com/a/2593752/1184579">this answer</a>. My Database Assistant code: <pre><code>public class DatabaseAssistant { public String filNameFullPath; public long filNameTS; public String EXPORT_FILE_NAME; //private static final String EXPORT_FILE_NAME = "/sdcard/datanaexport.xml"; private Context _ctx; private SQLiteDatabase _db; private Exporter _exporter; public String newfilename(){ System.out.println("inside newfilename()"); filNameTS = System.currentTimeMillis(); filNameFullPath = Environment.getExternalStorageDirectory().getPath(); EXPORT_FILE_NAME = filNameFullPath + "/" + filNameTS +".xml"; System.out.println("new file name: " + EXPORT_FILE_NAME); return EXPORT_FILE_NAME; } public DatabaseAssistant( Context ctx, SQLiteDatabase db ) { _ctx = ctx; _db = db; newfilename(); try { System.out.println("inside try databaseAssitant() -- file name: " + EXPORT_FILE_NAME); // 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 { System.out.println("inside try exportData()"); _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 { } } </code></pre> And in my main activity(called under onClick of a button): <pre><code>DatabaseAssistant DA = new DatabaseAssistant(myContext, mySQLiteDatabase); DA.exportData(); </code></pre> Here ^ (above is declared as): <pre><code>private Context myContext; private SQLiteDatabase mySQLiteDatabase; </code></pre> Any suggestion is appreciable.. Thanks
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<java><android><xml><sqlite><android-sqlite>
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Exporting SQLite Table data as XML
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