Question

有人可以帮助我如何纠正它!!!

package com.indoreencyclopedia;

import java.io.FileOutputStream;
import java.io.IOException;  
import java.io.InputStream;
import java.io.OutputStream;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;


public class HistoryActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.history);

 /* here it shows to remove invalid modifier "Public"*/

public static class DataBaseHelper extends SQLiteOpenHelper{


        private static String DB_PATH =         "/data/data/com.indoreencyclopedia/databases/";

        private static String DB_NAME = "MyLocation";

        private SQLiteDatabase myDataBase; 

        private final Context myContext;


        public DataBaseHelper(Context context) {

            super(context, DB_NAME, null, 1);
            this.myContext = context;
        }   

      /**
         * Creates a empty database on the system and rewrites it with your own   database.
         * */
        public void createDataBase() throws IOException{

            boolean dbExist = checkDataBase();

            if(dbExist){
                //do nothing - database already exist
            }else{

                //By calling this method and empty database will be created into the default system path
                   //of your application so we are gonna be able to overwrite that database with our database.
                this.getReadableDatabase();

                try {

                    copyDataBase();

                } catch (IOException e) {

                    throw new Error("Error copying database");

                }
            }

        }

        /**
         * Check if the database already exist to avoid re-copying the file each time you open the application.
         * @return true if it exists, false if it doesn't
         */
        private boolean checkDataBase(){

            SQLiteDatabase checkDB = null;

            try{
                String myPath = DB_PATH + DB_NAME;
                checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

            }catch(SQLiteException e){

                //database does't exist yet.

            }

            if(checkDB != null){

                checkDB.close();

            }

            return checkDB != null ? true : false;
        }

        /**
         * Copies your database from your local assets-folder to the just created empty database in the
         * system folder, from where it can be accessed and handled.
         * This is done by transfering bytestream.
         * */
        private void copyDataBase() throws IOException{

            //Open your local db as the input stream
            InputStream myInput = myContext.getAssets().open(DB_NAME);

            // Path to the just created empty db
            String outFileName = DB_PATH + DB_NAME;

            //Open the empty db as the output stream
            OutputStream myOutput = new FileOutputStream(outFileName);

            //transfer bytes from the inputfile to the outputfile
            byte[] buffer = new byte[1024];
            int length;
            while ((length = myInput.read(buffer))>0){
                myOutput.write(buffer, 0, length);
            }

            //Close the streams
            myOutput.flush();
            myOutput.close();
            myInput.close();

        }

        public void openDataBase() throws SQLException{

            //Open the database
            String myPath = DB_PATH + DB_NAME;
            myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);

        }

        @Override
        public synchronized void close() {

                if(myDataBase != null)
                    myDataBase.close();

                super.close();

        }

        @Override
        public void onCreate(SQLiteDatabase db) {

        }

        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        } 

}
}
}

Answer 1

您的问题是您缺少onCreate方法的结束大括号。或者更准确地说，你的结束大括号位于文件的底部而不是方法的末尾。

Answer 2

Android并不关心。但由于Java标准，它无法实现。忘了它并重构你的代码。将Helper类放在自己的java文件中。

android是否允许另一个公共类中的一个公共类？

2 个答案: