Question

所以我的应用程序使用内容提供程序和SQLite数据库，类似于Google记事本示例。我发现SimpleXML并希望使用它来导入/导出数据库，以便它可以在设备之间传输。我找到的唯一例子是example. 我想不必写一些中间类来传入/传出数据库。有没有人找到一个简单的方法，甚至可能没有simplexml？

Answer 1

您是需要导入/导出整个数据库还是只导出部分数据库。对于应该传输完整数据库的情况，您可能只是复制数据库文件本身，该文件通常存储在/ data / data / YOUR_APP / databases

中

Answer 2

public class DataXmlExporter extends DataBaseDemoActivity {

   static final String DATASUBDIRECTORY = "bookwormdata";

  // private final SQLiteDatabase db;
   private XmlBuilder xmlBuilder;
   Button butt;

  /* public DataXmlExporter(final SQLiteDatabase db) {
      this.db = db;

   }*/

   public void onCreate(Bundle savedInstanceState)  {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main7);


  butt=(Button)findViewById(R.id.exportxml);
  String exportFileNamePrefix=exportxml;
    // public void export(final String dbName, final String exportFileNamePrefix) throws IOException {
      Log.i(Constants._COUNT, "exporting database - " + dbname + " exportFileNamePrefix=" + exportFileNamePrefix);

      try {
        xmlBuilder = new XmlBuilder();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
      xmlBuilder.start(dbname);

      // get the tables
      String sql = "select * from dept";
      Cursor c = db.rawQuery(sql, new String[0]);

      if (c.moveToFirst()) {

          //while (c.moveToNext()) {
            String tableName ="dept";//c.getString(c.getColumnIndex("dep_id"));

            // skip metadata, sequence, and uidx (unique indexes)
            if (!tableName.equals("android_metadata") && !tableName.equals("sqlite_sequence")
                     && !tableName.startsWith("uidx")) {
               try {
                exportTable(tableName);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            }
         // }
        }
      String xmlString = null;
    try {
        xmlString = xmlBuilder.end();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
      try {
        writeToFile(xmlString, exportFileNamePrefix + ".xml");
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
      Log.i(Constants._COUNT, "exporting database complete");
      Toast.makeText(DataXmlExporter.this, "DB xml backup Successfully", 2000).show();

      butt.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                Intent intent = new Intent(DataXmlExporter.this, DataBaseDemoActivity.class);
                startActivity(intent);
                        }
        });
   }

   private void exportTable(final String tableName) throws IOException {
      xmlBuilder.openTable(tableName);
      String sql = "select * from " + tableName;
      Cursor c = db.rawQuery(sql, new String[0]);
      if (c.moveToFirst()) {
         int cols = c.getColumnCount();
         do {
            xmlBuilder.openRow();
            for (int i = 0; i < cols; i++) {
                /*if(i==6)
                {
                    //String id = c.getString( c.getColumnIndex("photo"));
                    String str = new String(image);
                    xmlBuilder.addColumn(c.getColumnName(i), str);
                }*/
               xmlBuilder.addColumn(c.getColumnName(i), c.getString(i));
            }
            xmlBuilder.closeRow();
         } while (c.moveToNext());
      }
      c.close();
      xmlBuilder.closeTable();
   }

   private void writeToFile(final String xmlString, final String exportFileName) throws IOException {
      File dir = new File(Environment.getExternalStorageDirectory(), DataXmlExporter.DATASUBDIRECTORY);
      if (!dir.exists()) {
         dir.mkdirs();
      }
      File file = new File(dir, exportFileName);
      file.createNewFile();

      ByteBuffer buff = ByteBuffer.wrap(xmlString.getBytes());
      FileChannel channel = new FileOutputStream(file).getChannel();
      try {
         channel.write(buff);
      } finally {
         if (channel != null) {
            channel.close();
         }
      }
   }

   /**
    * XmlBuilder is used to write XML tags (open and close, and a few attributes)
    * to a StringBuilder. Here we have nothing to do with IO or SQL, just a fancy StringBuilder. 
    * 
    * @author ccollins
    *
    */
   static class XmlBuilder {
      private static final String OPEN_XML_STANZA = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";
      private static final String CLOSE_WITH_TICK = "'>";
      private static final String DB_OPEN = "<database name='";
      private static final String DB_CLOSE = "</database>";
      private static final String TABLE_OPEN = "<table name='";
      private static final String TABLE_CLOSE = "</table>";
      private static final String ROW_OPEN = "<row>";
      private static final String ROW_CLOSE = "</row>";
      private static final String COL_OPEN = "<col name='";
      private static final String COL_CLOSE = "</col>";

      private final StringBuilder sb;

      public XmlBuilder() throws IOException {
         sb = new StringBuilder();
      }

      void start(final String dbName) {
         sb.append(XmlBuilder.OPEN_XML_STANZA);
         sb.append(XmlBuilder.DB_OPEN + dbName + XmlBuilder.CLOSE_WITH_TICK);
      }

      String end() throws IOException {
         sb.append(XmlBuilder.DB_CLOSE);
         return sb.toString();
      }

      void openTable(final String tableName) {
         sb.append(XmlBuilder.TABLE_OPEN + tableName + XmlBuilder.CLOSE_WITH_TICK);
      }

      void closeTable() {
         sb.append(XmlBuilder.TABLE_CLOSE);
      }

      void openRow() {
         sb.append(XmlBuilder.ROW_OPEN);
      }

      void closeRow() {
         sb.append(XmlBuilder.ROW_CLOSE);
      }

      void addColumn(final String name, final String val) throws IOException {
         sb.append(XmlBuilder.COL_OPEN + name + XmlBuilder.CLOSE_WITH_TICK + val + XmlBuilder.COL_CLOSE);
      }
   }

}

试试这个。这对我有用。

我想使用SimpleXML在Android中导出/导入SQLite数据库

2 个答案: